Modifications for the Uniden HR2510

19-07-1998 HR2510 - Lincoln Web site English language
19-07-1998 Tips and trick for the HR2510 English language
19-07-1998 Information on the HR2510 10 meter radio English language
19-07-1998 Expanded frequency coverage for the Uniden HR2510 English language
19-07-1998 Speed up the AGC for Uniden HR2510 English language
19-07-1998 Output power mod for the Uniden HR2510 & HR2600 English language
19-07-1998 HR2510 RIT-control mods English language
03-01-1999 Adding 24-26 MHz to the HR2510 & 2600 English language
20-10-2001 Frequency modification: President/Uniden HR-2510 English language
20-10-2001 HR2510 Modification for increased MicGain English language
20-10-2001 President or Uniden HR-2510 Variable Power Modification English language
20-10-2001 Increasing the power output for the HR2510 or Lincoln English language
20-10-2001 HR2510 Hi-Power modification (Better and easier) English language
20-10-2001 Modification of the HR2510 Mic buttons to operate the VFO English language
20-10-2001 Talkback removal English language
20-10-2001 HR2510 RIT / Clarifier Mods English language
20-10-2001 HR2510 Misc. Enhancements English language
20-10-2001 24 MHz Broadband instructions for your HR2510 English language
20-10-2001 HR2510 Alignment Instructions English language

HR2510 - Lincoln Web site

HR2510 - Lincoln Web site - Home of the Lincoln Federation

This modification is read 591 times.

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Tips and trick for the HR2510
Author: Josh Steele


The following article was compiled from ,notes that brother Jack passed on to me on conversations that we have had. This is firsthand information that Jack gathered from his study of the HR2510 when if first come off the production line.

As you know, the HR2510 is a mobile 10-meter transceiver radio recently introduced into the market by the Uniden Corporation. Rumor has if that if is easily convertible to on 11-meter radio, but the manufacturer would never admit so that. Let me fell you, however, that the rumor is definitely true.

This radio is hot!. It is so hot that distributors can't keep the radio in stock. And, as Jack reports to me, Uniden can't fill their orders to heir distributors. They cannot produce enough the radios in the Orient. A large shipment was received in the states recently, but it only mounted to a fraction of the number that has seen ordered from the company.

The HR2510 is for the CBer who has verything. If can expand your horizon into a hole new area. As Uniden's own literature tates, it "opens up 10 Meters to more people that ever before." If you're a lover of export radios, you'll love this unit. It is an idea whose has come.

The begin with, the radio has a lot of outstanding features. It is the only mobile radio we know of that has VF0 (variable frequency output) control. The VFO works on transmit and receive (the RIT control, however, only works on receive) and it will allow you to change channels by 100 Hz to 1 KHz. It has built-in roger-beep, built-in scan, and an automatic key. It has a band-select that jumps fifty channels per scan which makes it easy to find the action. There is a frequency lock that will prevent you from getting off frequency if you accidentally hit the channel knob. The lock blocks any changes from the P. L. L. The radio's display reads out the channel as well as the frequency. You have all the meters you need including SWR, RF, modulation, and calibration. The radio has 10-watt power on the AM and 25-watt on the sideband. It also has automatic squelch, noise blanker and much more.

Of course, the real beauty of this radio is that happens to it after it is converted. I would never encourage anyone to engage in this illegal activity, but I will provide this information for EDUCATIONAL PURPOSES ONLY for my readers who reside outside of the United Stales. If the HR2510 is expanded to the 11th meter band, this is what you get. The power output goes to 25 watt on the AM with slide up to 35 and 45 watts on the sideband.
You get every channel between 26.000 and 29.999! You don't miss any! You can go straight through the band without skipping any channels! (Contrary to rumors, you do not lose the 10 meters offer conversion.) The scan feature that comes with the radio will allow you to scan all 40 channels on the CB band. In addition, after modification, the radio will allow you to jump past all of the RC channels. In other words, if you flip the channel selector to the 10 KHz mode it will jump through the C8 bond and skip lhe RC channels and give you a tru, channel read-out. And as on extra added bonus, after this radio i converted, you get automatic talkback

For what it is capable of, the HR2510 has very little competition in the market. Its main competitors would be the Galaxy and President Lincoln Export radios and the Ranger AR-3500. And how does it stack up against those competitors.
Well, compared to the Galaxy, it has many more features, gets many more channels and is more powerful. Since the Galaxy is on illegal radio, the HR2510 is generally much easier to find.

As for the Ranger, it is more difficult to convert than the HR2510 and more expensive. And it will skip channels. I agree with my brother Jack, also, when he says that the Ranger is just too gaudy. The HR2510 is a better looking radio.


The President Lincoln Export radio is the version of the HR2510 that Uniden makes for sale overseas. It already has the 11th meter band. If is made to look and act like on HR2510 after conversion. If falls short in the performance category. There are problems with the reception cutting in and out and its variable power output has a tendency to slide back on power. Like the Galaxy, the Lincoln is illegal which makes it hard to find and even harder to get anyone to service. To top if off, it is more expensive the HR2510.


Let me add a note on the driver and final used in the HR2510. The driver in the radio is the 2SC2166. This driver is completely interchangeable with the final found in most radios including the Cobra 2000GTL and the Uniden 710E and it can handle up to 20 watts of power. The final is the MRF477. It can handle about 50 watts of power. This is further indication that the radio was built for power.

The radio has an AN612 balance modulator which is the same one found in the Cobra 14BGTL. It uses a 10 MHz I. F. like the Cobra 146GTL. As a result, the receive is very similar to the 146. The transmit is close to that of the Jackson Export, but instead of using coils, like the Jackson, the 2510 utilizes a wide-band toroidal transformer at outputs to eliminate tuning and to get the wide bandwidths needed to operate the 26 MHz to 30 MHz.

One fascinating feature of the HR2510 is its use of several circuit boards instead of the usual one circuit board found in other radio. Next month, we will explore the purpose, use and effectiveness of these boards. In coming months, we will try to provide conversion information for our readers living outside of the United States. Be looking for it.

As I said at the beginning of this article, this radio is selling strongly. Uniden is doing al it can to keep its distributors supplied, but can't quite keep up. So you may want to order your supply now from your distributor.

One final note. The HR2510 does require a ham operator's license for operation as an amateur radio. However, it is very simple to gel one and that should not pose any obstacle to someone who is interested in purchasing the unit.

Depression still gripped the' country. So my friend's grandpa chose bootlegging as a profession and he did mighty well at it.

Of course, since bootlegging was so lucrative, the competition in the market was fierce. Some of the competition were not believers in the American free enterprise system, however. ' They would hove liked to have had no competitors- whatsoever. They wanted a monopoly and they were powerful people.

One night, my friend's grandpa was making one of his deliveries up in the "hollers" somewhere. His competition look the' opportunity to "liquidate" 11I5 (business. He was never heard from again

Now, these competitors of his wanted to make sure that everyone got the message, shortly after his "disappearance", his wife, or should I say widow, received something in the mail. Tucked in an envelope was her husband's ring finger.

Competition can get rough sometimes


As I promised last month, we are going to provide the readers with some technical information on the circuitry found in the HR2510.

The 2510 has two main circuit boards. One is the P8121A8. This board house a 5 volt regulator, an 8 volt regulator, and the microprocessor. The microprocessor is the UC1170 DIP (Dual In-line Package) chip and it controls the bandwidths, channels, frequency, readouts,etc..

In effect, if controls the Whole radio. The PB121BA also contains the 0305A, a serial PLL. which is fed directly by the microprocessor thus avoiding the pin-jumping needed in older radios. Modification is performed by programming the pins on the microprocessor, allowing you to obtain the extra bandwidths you want. Two 5042P mixer chips ore also on this board. These are the same chips used on the 14BGTL. They do the mixing in the VCO (Voltage Control Oscillator) and they make the VCO very stable.

The other main board, which is controlled by the microprocessor, is the PB111AB. The MR477 final, the 2166 driver and the AN612 balance modulator mentioned in last month's article are located on this board. It also contains the complete audio, receive and transmit circuitry. The audio IC chip is a TDA1905, a full 7 watt IC DIP chip that is being used on all new Uniden radios. It is somewhat unusual in that is a 14 -pin chip rather than a flat pack, but it most work very well because Uniden has been using it for some time. The receive uses a 455KHz IF (Intermediate Frequency) which gives you a crystal filter for reception. The resulting narrower bandwidth causes better rejection and helps prevent bleedover. The AMC (Automatic Modulation Control) is handled by the VR114 variable resistor.
The VR104 variable resistor handles ALC (Automatic Level Control). When fully cranked up, if con swing to 55 to 60 watts at peak. The AM power control is a VR103 variable resistor.

The radio also contains several other smaller circuit boards that perform specific functions.

The PB119A is the FM receiver board and enables the radio to pick-up the FM frequencies.

The PB117AA is the noise blanker and AM detector board and if allows operation on the AM band. There are different boards because this is a multi-mode radio. To get the mode desired, the appropriate board is plugged in and soldered into place.

The PB100A8 is the collector current adjustment board. You can pull the board and put a current meter between each of the pins to set up the bias an the finals.

The PB118AA SWR board has the SWR meter on it. Information is sampled by this board and sent to the microprocessor. This board determines what you see on the front of the radio.

The PB112 is the digital readout board. It has a IR2429 IC chip on if which is the driver for the LCD display. It takes information from the microprocessor and feeds it to the display.

Those are the most important boards in the radio. There are several other subboards in the front of radio for volume control, modulation selector switches and things like that, but I'm not going to go into them here. I hope this information will be helpful to my readers, particularly those who are ham operators. I maintain that this is a lot of radio for the price. You can certainly get more sophisticated equipment, but You're going to have to pay for it.

Now, about the conversion of this radio. You know that is illegal and I would never encourage my readers to engage in illegal activities. But for my readers living outside the United States.

I will provide you with some information that Brother Jack picked up recently. Of course, this information is all hearsay because we all know that Jock would never actually alter a radio himself. About all I can tell you for now is that there are two methods of modification. One method has something to do with pins 34 and 35 on the microprocessor. The other method involves pin 36 in addition to 34 and 35. It is amazing how much more you con find out with a self-addressed stamped envelope.


Last issue, we discussed the problems Cobra and Uniden were having supplying their distributors with adequate quantifies of the 2000GTL and the HR2510 respectively. Brother Jack reports that the shortages my extend to other manufacturers and other products. In foci, almost anything of an electronic nature including scanners, VCRs, stereos, etc.., may be in short supply this Christmas season. Most items of this nature, of course, are manufactured in the Orient. Jack says the manufacturers cannot get enough parts from their suppliers to enable them to maintain sufficient production. Look for increasing prices as Christmas approaches.


In the course of my work, I am fortunate to do a !lot of travelling Recently, I stopped of a small diner in the Midwest for lunch on my way home. Right after I sat down in my booth, I saw meter, and RF/MIC gain, vofume/squelch, clarifier, SWR calibration controls, among others.

Brother Jack reports that rumor has it that there is a kit available for very easy conversion of this radio. The radio is so new neither Jack nor I have had an opportunity to open it up. As soon as we find out more about it, we'll fill you in on the details.


Dear Jack,

...I know of some people that have tried to make a base station antenna and hove had very poor luck. Including myself. We have used aluminium and fried to make them the some as you buy, but we are not getting something tight. I would like to make On omnidirectional like the pig stick..E.L., Paris, TX

Dear E.L.,

It is difficult to advise you based on the information you provided. I would want to know, for example, what type of radio you had, what kind of talking you prefer to do, what your physical surroundings are like, etc.. But for all the time, effort, and money you are going to have to invest into such on enterprise, you might be better off staying with an Antron or Big Stick, If you can get them at reasonable prices. The Antron is a great antenna for the money and it has 9.9 dB gain.

Hello Jack

I...was impressed on your article about the Uniden 2510. I have converted several of these radios, but I can only get 12 to 15 watts output on SSB and 8 to 10 watts on AM. I was wondering if there are some other changes you must make to get 25 watts AM and 40 to 45 watts SSB?... Also, I have a 2510 that I can only get about 15 to 20 MA reading from the driver by adjusting VR112. I can get my 50 MA by adjusting VR113 on the final. Do you think the 2SC2166 is operating correctly? Belleville, IL

Dear Belleville,

Let me say that i am absolutely shocked that any of my readers living in the United States would actually convert these radios.

It sounds like you have successfully gotten your extra channels, but you're going about increasing your power in the wrong way. You are apparently trying to get more power by changing your bias. Not a good idea. Leave the VR112 and VR113 alone.

The best WAY to get more power out of the RADIO is to turn up the ALC (for sideband, it's the VR104) and the AM Power (for AM, it's the VR103). This should take care of your power problem, but be sure not to turn up the AM Power above 20. For more modulation, you can adjust your AMC (VR114)


The HR251 0 is a "fantastic radio".. BH, Cleveland, OH

"...the HR2510. I bought one and love the hell out of it. It's the best radio that I've ever had, and I've had about every one you could name..."...G., ,Junction City, KS

"...I found that a 'Turner plus three desk Mic with very little gain applied makes the HR2510 sound very impressive as a base station."..BW, Batavia, OH


I've been getting a whole lot of mail concerning HR2510. One question that keeps coming up concerns converting the RIT control into a clarifier that controls transmit frequency as well as receive. I'm still working on that project and I hope to whrite about it in a future article. Here are same more questions I've been getting on the HR2510:

Dear Jack,

I run a JBl2 modulator that drives a Palomar 300A linear (amplifier) and I'm afraid that the HR2510 would be too much of a driver to use in my setup"...HF Groto, of a driver.
Read on.

Dear Josh,

If you decide to run some "heat" with the HR2510, what would you turn the radio down to and what "heat" would he a good one to use..G, Junction City, KS

Dear Gene,

I have found that the radio's best audio is at 10 watts deadkey and that's what I recommend. The peak of the 2510 is a little high to kick some amplifiers, as I mentioned in the case above. I would use at least something like a Texas Star 600. Anything else may be overdriven.

Dear Mr. Steele

I hear a rumor that there are two pods inside (the 2510) for increasing power. I have only found one, the ALC, an d have turned it up all the way and can only get 30 to 35 watts on sideband and about 24 on AM...JA, 'Tuscaloosa, AL

Dear JA, I covered this ground in an earlier article, but I still get a whole lot of mail about it. You're on the right track Adjusting the ALC "pot" will increase power the sideband. If you keep looking, you'll eventually locate the AMPWR "pot". Looking down from the top of the radio, it is situated in the left-hand corner and is clearly marked. Adjusting this "pot" will increase power on AM. I can't explain the thirty to thirty-five watts unless you're using a RMS meter which may not give you a truly accurate reading of your peak power output.

This modification is read 1236 times.

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Information on the HR2510 10 meter radio

  1. The HR2510 uses a driver and final in conjuction to giving you full 25 Watts on SSB.

  2. The driver in the HR2510 is completely interchangeable with the finals found in most radios like cobra(2000GTL) and the uniden (710E) and it can handle up to 20 watts of power. The driver in the HR2510 is (2SC2166).

  3. The final in the HR2510 is a (MRF477) it can handle about 50 watts of power. This is a further indication that the radio was built for power.

  4. The HR2510 has (AN612) balance modulator which is the same found in a cobra (148GTL) CB radio.

  5. The HR2510 uses a (10 MHz i.f.) like the cobra (146GTL) CB radio. As a result, the receive is very similar to the 146GTL CB radio.

  6. The HR2510 instead of using coils, like the Jackson radios. The HR2510 utilizes a wide - band toroidal transformer at outputs to eliminate tuning and get the wide bandwidths needed to operate the (26 MHz to 30 MHz).

This modification is read 1682 times.

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Expanded frequency coverage for the Uniden HR2510

This radio covers a full 26-30 MHz with a simple 10-minute circuit change.
No further realignment is even needed, since it uses broadband tuning and was designed to cover all this range in the first place.

  1. Locate pins 34 and 35 of the main up chip IC315. (called "UC1201A", UC117", etc.) This is the largest chip on the synthesizer board, PB121BB.

  2. These pins are grounded on the HR2510 , but are tied high (5.0 VDC) on the european models like the president liincoln. All thats required is to break the grounding pc trace and tie them instead to a +5.0 VDC source through a pullup resistor.

  3. On the solder side of the synthesizer pcb, youll notice that pin 34 and 35 are soldered together and are connected to the main ground foil. Using a razor blade or exacto knife, cut the foil at a narrow spot to break this connection.

  4. Now notice that the left-most pin of pullup resistor pack RR301 is unused and goes to an isolated island foil pad.(How coincidental!) Just tack a small jumber wire between this pin of RR301 and the pad of IC315 pins 34 and 35, and you'll be in business!
You now have a radio useful not only for 10 meter ham operation, but also for listening* to the kind of road information and emergencies for which CB has proven itself repeatedly. The indicated coverage on the front panel will be:

*don't transmit, this isn't a type accepted radio!

Band A = 28.000 to 28.490 MHz
Band E = 26.000 to 26.490 MHz
Band B = 28.500 to 28.990 MHz
Band F = 26.500 to 26.490 MHz
Band C = 29.000 to 29.490 MHz
Band G = 26.965 to 27.405 MHz
Band D = 29.500 to 29.990 MHz
Band H = 27.000 to 27.490 MHz
Band I = 27.500 to 27.990 MHz

Band "G" is the standard CB band starts up at CH.9, 27.065 MHz.

I haven't tried this, proceed at your own risk. And.....
***DO NOT transmit outside of the Ham band!***
(you don't want to loose your license!)

Use the above to listen only, or for use with a transverter.
Or use with a dummy load, to generate test signals for checking receivers.

This modification is read 2208 times.

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Speed up the AGC for Uniden HR2510

Is your 2510 slow on agc??? does it take 3 frames at 1200b for the rx to come up to sensitivity?? do you want to make the rit a rtit (rxtxit) then maybe these mods will help you, they also may apply for the newer versions of this radio, you who have the 2600 may be able to use them.

Mod 1.

Speed up agc, this is easy, just pull out the transistor Q111 and you have fast agc, if you need to select slow agc then put a switch from the collector to emitter and pull the collector pad to ground for slow agc.

Mod 2.

Make the tx and rx both responde to the rit control and reduce the amount of frequency change for the control.
This one requires that you locate the rit control and remove the following: R802 a 1k resistor in series with the rit pot.
The RX 8v line that goes to high side of pot, remove and put aside, you will need it for power to nb switch and rf gain control.
Now remove the subassembly b801 pb-120 and remove r802. cut pc land between high side of vr802 and r 801 you will now solder the rx 8v line to the freed side of r 801.
The 1k resistor, r 802 will be replaced with a 100k resistor, and a line will be taken from the 8v side of IC 107 the 8v regulator to a resistor network that will give aproximately 52k (you will need to experiment to get a value such that you rit pot will give you readout frequency when the feducial line is pointed at center)
Lift one side of diode D150, this will free the pot VR111 from the line that feeds the varactor on the pll board. You may use the pot in conjunction with a 50k resistor (47k) to set the rit pot to center position, by putting it in series with the 50k resistor and adjusting. This combinations will give aproximately +-300hz either side of readout freq.
The best way to use the pot vr111 for this is to lift a jumper that runs to the land on the high side of the pot and solder the 50k resistor to this land. run a wire from the other side of the resistor to +8v (make sure it is not tx or rx 8v since that is switched on or off depending on what state radio is in tx or rx)

Having done these mods you will have a radio with a fast agc and a rtit control that will give the narrow changes needed for packet. the radio will be quite stable. now to see about putting a g3ruh modem on the varactor of the radio hmmm anyone for 4800b or 9600b on 10m (you gringos get a sta and lets try it, could be interesting!!)
For this bit of work, i also got in the bargain a rx to tx time of abt 20ms i can send frames with a txd of 3 on my tnc-2 clone and the local switch will receive it just fine. there is enough front porch for all the radios which run open squelch or direct from the detector to copy the 1st frame out of the box!! (all our switch and bbs radios run 2211 modems connected direct to the disc or detector here in costa rica, thereby getting rid of a lot of problems of switches and bbs not copying the users.)
if you have any mods for the 2510 or i think the radio shack 10m radio is of the same insides, please send them, lets put a lot of these boxes on packet and scare some of that cb and other illegal operations off 10m now!

Ciao and enjoy de chuck

This modification is read 2595 times.

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Output power mod for the Uniden HR2510 & HR2600

Uniden's HR2510 & HR2600 10 Meter Amateur radio's are nice for single band operation, but a little more output power is desirable for portable use.

M.T. Stacey KC4HGH in Septembers issue of 73 Amateur Radio (1989)
Published his findings on power modifications to the HR2510.

The modifications that follow are based on his works with some additions:

The factory has the HR2510 & HR2600 output power levels set for continuous duty. I.E. AM,FM & CW 10 Watts, SSB - 20/25 Watts. The radio is capable of much more output power for intermittent operation like SSB.
**************************** POWER MOD ********************************

  PROCEDURE                    HR2510             HR2600

Relocate capacitors to         C122,C116          C122,C116
bottom of Board. (This
is to allow spreading of
the tuned/trap output

Replace Pre-driver Tx
(2SC2086D) w/ ECG-340          Q124                Q34
(Note pinout change)
2510/2600's w/ the
2SC1973 device require
no pinout change.

Replace output Device
MRF477 w/ MRF497               Q132                Q32

Replace Bias current           R158                R158
limiting resistor from
82 ohms to 68 ohms
1/2 watt device.

Pull bias jumper board
out of the circuit.            PB100               PB100
Place a current meter
(100ma) between pins
TP2 and TP4

Adjust Final bias for
80-85 MA, USB position.        VR112               VR13
No Modulation.

Fire radio up with
power meter and 100W
dummy load attached.
Adjust ALC for Maximum.        VR104               VR5
1Khz tone is helpful.

Mode to AM/FM
Spread coils                   L121,L123           L14,L16
for maximum.

AM/FM power adjustment,
20 Watts is easily obtained.
I think 25/30 may be pushing
it in this Mode. (Melt Down.)
Adjust controls for your       VR103,VR107         VR4,VR8
desired levels.

My experience in increased output levels are as follows: "SSB Mode."

HR2510 = 32 Watts RMS (1Khz Tone) / 45.2 Watts PEP

HR2600 = 37 Watts RMS (1Khz Tone) / 52.3 Watts PEP

The above measurements are made with Bird 43 into a 50 ohm load.


1320 Grand Ave.
San Marcos CA. 92069

This modification is read 3113 times.

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HR2510 RIT-control mods
Author: Dave Schmarder, N2DS

In my recent quest to find mods for the Uniden HR2510 10-meter rig I received a lot of inqueries into my findings, so here it goes - the first real 'mod' I've found for the HR2510.
My thanks to Dave, N2DS for supplying the information and original notes on his mod. (Dave can be contacted at the N2EZG pbbs.

I bought one several months ago and found that the RIT control didn't work the way I wanted it to. The problem is that the TX and RX are unlocked from each other and if you wish to transceive, you had better make sure that the control is in the right position. I decided that it wasn't suitable that way, so I locked the transmit with the receive. There were two problems that arose when I did the mod. The TX and RX frequencies on USB were shifted by about 50hz or less, noticable, but not serious.
We all operate USB on 10 anyway, but could cause difficulty on RTTY/AMTOR. The other problem was that on CW, you would have to zero beat the station to be on his frequency. I solved that by placing a relay circuit in the line to return the RIT to original operation on the CW mode. I am sending you the original notes concerning this to pass along."
  1. Remove cathode end of D150 from circuit board. Connect two wires, 1 of each to cathode of D150 and to where the cathode used to go in the board.

  2. Connect other ends of these wires to the N.O. Contacts of the relay.

  3. Find & clip ORANGE wire going to board near D119. Leave enough wire to board to connect new wire. Solder ORANGE wire removed to the common contact of other side of DPDT relay.

  4. Connect wire from where that orange wire went (near D119) to N.O. contact of the DPDT relay (same side as orange wire went).

  5. Connect wire to where RED wire near D172 is connect. This added wire is connected to the N.C. contacts on relay on the same side as the orange wire.

  6. Connect free end of 2.7ohm resistor to VIOLET wire near D176.

  7. Connect emitter of 2N3904 to black wire near D160

  8. Connect wire from relay and cathode of 1N4148 to red wire near D154.

This modification is read 3526 times.

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Adding 24-26 MHz to the HR2510 & 2600


  • D1 is a general purpose silicon rectifier diode
  • C1 is a trimmer cap -(somewhere around 5 - 100 pF)
  • X1 is the 22 MHz crystal that was in X302
  • X2 is a 19.995 - 20.000 MHz crystal
    19.995 might make it easier to get both band on frquency
After this modification you will have to get the radio back on frquency by first adjusting the pot labeled TX FREQ while the toggle switch is in the normal(10-11maters) position.

Then press the roger beep switch and it will subtract 2 MHz from the displayed frquency (if display reads 26.95 you will be on 24.95 MHz).
Now you have to set the 24-26 MHz part on frequency by adjusting C1. When both "bands" are on frequency everthing should be fine, just press the roger beep (or whatever switch you used) to subtract 2 MHz!.

Note: If the power output is to low around 24-25 MHz, you might want to mess with L319 and L310 to widen the bandwidth of the radio - I was able to get about 30-40 watts PEP on 24.94 MHz and that's what it does on 10 meters band also.

If you have any questions about this mod, e-mail to

This modification is read 4008 times.

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Frequency modification: President/Uniden HR-2510
Author: VE2XQQ

Remove the cover on the speaker side of the radio. You will need to loosen the 4 screws (2 on each side) that secure the SYNTH PCB Frame to the chassi. - You do not need to remove these screws - You need to remove the 4 screws that secure the SYNTH PCB to the metal frame.

Now flip the SYNTH PCB over, Locate the pins of the Microprocessor. In some versions of the HR2510 there may be Grey Epoxy covering one end of the Microprocessor. You may be able to peel the epoxy right off to expose the pins of the IC. If it is not soft enough to peel off, you can use a 400W hair dryer to heat the epoxy enough to remove it.

Cut the ground trace connected to pins 34 & 35, jump pins 34 & 35 to the free end of Resistor pack RR301 (see diagram) or connect a 4.5K -15K ohm resistor from pins 34 & 35 to pin 3 of IC312 (5V regulator).

This will give complete coverage from 26.000 MHz to 29.699 MHz (Some radios will go to 29.999 MHz)

Thanks toVE2XQQ for the mod and schematic.

This modification is read 4564 times.

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HR2510 Modification for increased MicGain
Author: VE2XQQ

This mod will increase the AM modulation.

The AM modulation adjustment is VR114, which is marked ëAMCí on the main circuit board.

To get more, Q114 is the Mic Attenuator, This limits the audio.

Q114 is located near the front of the circuit board in the center to the left of IC 104, above C153.

To modify this, remove Q114 and bend the Emmitter leg up from the circuit board and re install.

Put a 1000 ohm resistor in the vacant hole and solder to the board.

Solder the other end of the resistor to the Emitter leg of Q114.

This will allow more modulation with the ëstockí mic, and will allow a Power Mic to truly perform! The AMC control will still function so using a modulation meter you will be able to set it to avoid overmodulation.

Another Mod Suggests Clipping D129 to remove the ALC and AM limiting. I have heard from one user that this mod works exceptionally well.. I have not tried this mod, If anyone else has , please let me know the results.

Thanks toVE2XQQ for the mods and schematic.

This modification is read 4752 times.

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President or Uniden HR-2510 Variable Power Modification
Author: VE2XQQ

The HR-2510 does not have a varible output power feature as it comes from the manufacturer. The following modification will allow you to fix that oversight. This Mod will vary the power on AM and SSB.

Thanks toVE2XQQ for the mods and schematic.

This modification is read 4929 times.

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Increasing the power output for the HR2510 or Lincoln
Author: VE2XQQ

  1. Remove the top and bottom covers.

  2. Locate and remove Q132 & Q134.

  3. Replace Q134 with an ECG 340 or TCG340.

WARNING!!! The leads of the two transistors are exactly opposite of each other.

    [ 2SC2086 = BCE ; ECG340 = ECB.]

  1. Replace Q132 with an MRF 497. ( Be sure to use heat sink compound.)

  2. Remove C132. (no replacement)

  3. Remove C112 & C116.

  4. Replace C112 with an 82pf capacitor, But put the new Capacitor on the bottom of the PC board.

  5. Replace C116 with an 100pf capacitor, But put the new Capacitor on the bottom of the PC board.

    Component Layout with Cross reference for the HR2600

  6. Connect power to the radio, and following the alignment procedures, adjust the bias of Q132 to 80mA +/- 5mA by adjusting VR112.

    [To adjust the bias of Q132: Remove the B002(PB-100) jumper board from the Main PCB.

    Connect a DC Ammeter (+) to TP4, (-) to TP3.

    With the radio on USB, Adjust VR112 for 80mA +/- 5mA on the DC Ammeter.

    After the adjustment is complete, Reinstall the B002(PB-100) jumper board.]

  7. Inject a two tone signal into the microphone of the radio while transmitting into a dummy load.

    Set VR104 (ALC) for maximum output..

    Retune VR107 ( AM /FM carrier level) for Maximum.

    Retune VR103(CW carrier level) for Maximum

  8. Again inject a two tone signal into the microphone of the radio while transmitting into a dummy load.

    Spread or contract coils L121 & L123 for the highest power out in the center of the band.

  9. Replace the covers and the screws, you should now have between 50 and 100 watts on SSB.

This mod was originally written by M.T. Stacey, KC4HGH in an article published in CQ magazine of September 1989 on page 48. There was also supposed to be an Update in ë73 magazine of November 1989 on page 76, Although I have never been able to find a copy to verify it. If you have a copy, Let me know, I would like to obtain a copy.

Copy of update by M.T.STACEY, KC4HGH

Due to a technical error, innacuracy in my original test setup, the PEP power levels on page 48 of sept. "73 Amateur Radio " were erroneous. After revamping the test bench equipment, and testing the new wattmeter against a Bird 43, the findings are as follows, In modified radios , 2-3 watts carrier , and 10-12 watts PEP average increase over the stock peaked-out radios. therefore, the original goal was reached, i.e. more power with better audio and less stress in the RF output section.

I sincerely apologize to everyone who have been inconvenienced by the original results printed. With regards to all, M.T.Stacey.

Thanks to: R, Madaire, 1227 Woodroffe ave. Ottawa,Ontario,CANADA. K2C 2T2

Thanks toVE2XQQ for the mods and schematic.

This modification is read 5127 times.

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HR2510 Hi-Power modification (Better and easier)
Author: Carl Merrill

By Carl Merrill

After reading the high power modification originally published in 73 Amateur Radio Today ("Beefing Up the Uniden and the HTX-100" by M. T. Stacey KC4HGH, September 1989. page 48) and then changed by the originally writer (73 Amateur Radio Today. "Update", November 1989, page 76), I discovered another methods that is easier to implement and has given consistent result.

The modification in the 1989 article and update requires you to change the output transistor from a type MFR477 to a type MRF497 then change the pre-driver transistor Q134 from a type 2SC2086 to a type ECG-340.

I found that the ECG-340 didn't really give any more drive to the driver transistor, for in is an emitter-follower, with a gain of less than one, so I left the 2SC2086 portion of the circuit alone.

The modification

The following modification will give you marked improvement in the power output of the HR2510 and is easy to implement:

  1. Change the output from a MRF477 to a MRF497 and make the necessary bias adjustments as follows:

    Connect the radio output to a 50 ohm dummy load and set the frequency to 28.005 MHz, USB mode, with no modulation.

    Hook up a meter (0-100 mA scale) between test points TP4 (+) and TP3 (-) to monitor final amplifier current.

    Key the transmitter with no modulation and adjust VR112 for 80 mA collector current (Q132).

    Place the meter's negative lead on TP2 and check the driver current.

    Replace VR113 for a driver current of 50 mA if necessary.

    Replace shorting bars into TP4, TP3 and TP2.

    While tuned to 28 MHz, adjust the AM power output to about 5 watts by adjusting VR107

  2. Turn off the power and locate Q134, the 2SC2086 amplifier transistor. Cut the foil (as shown in figure2) to remove the network from the emitter. Remove the 0.01 uF capacitor (C135) from the collector of this transistor to ground. Bridge the foil from the open end of the network to the collector foil. Now, solder the removed 0.01 uF (C135) th the bottom of the board from the emitter to ground. See figures 1 & 2 from details.

  3. Check your work carefully for any older bridges and turn onthe power. The AM output will normally jump up to about 15 watts after this modification.

    Turn the AM power output down to about 12 to 13 watts by adjusting VR107. This is plenty for this radio and will sound real nice on the air. You should find that the SSB power will now be around 25 to 32 watts.

  4. Adjust the SSB output for peak power by feeding a single 1 KHz tone (or dual tone) into the radio while adjusting VR104 (the SSB ALC pot.).

  5. If your radio needs further alignment, consult the appropriate service manuals for the HR2510 and the HTX-100. The MRF497 may be obtained from RF parts Company, 435 So. Pacific Street, San Marcos, CA 92069. Tel. (760) 744-0700.

Figure 1.
Figure 1. Modification for increased power for the Uniden HR2510. Top circuit is the original; bottom circuit is the modified version.

Figure 2.
Figure 2. Modification to the PC board, bottom view.


The purpose of this change is to make the 2SC2086 provide gain, for in an emitter follower configuration, the gain is always less than 1. It works better, and saves the cost of the ECG-340. I have completed this modification and they work fine. They can be heard in places they couldn't reach before.

This modification is read 5345 times.

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Modification of the HR2510 Mic buttons to operate the VFO
Author: VE2XQQ

Note: This modification is not needed if you have Chipswitched your radio already. The Chipswitch does this internally.

What these mods do is to disconnect the 5Khz steps and allow the Mic buttons to do what the Rotary switch does.

MOD # 1

The rotary switch applies 5 volts to activate the Up or Down control of the VFO.The Mic uses ground to activate the 5 Khz step control of the Up or Down buttons.The changes to the Mic are required because of these differences in the control operation.

The 1K resistor and 1N4001 diode combination causes the TX lead to be HI ë5 voltsí on receive and it protects the 5volt source on TX when the lead is grounded. (You must use a 1N4001 diode, because a 1N914 will not handle the current on TX).


  1. Open the Mic and remove the ground from the Up and Down Switches and connect the common of the switches to the TX lead. (see diagram below) Reassemble the Mic.

  2. Remove both covers from the radio and look for the Mic jack. You will find 2 resistors, one on pin #4 and the other on pin #5. Jump out both resistors with wire.

  3. Find J308, located on the top left corner of the Microprocessor board. Cut the Yellow wire from the connector, leaving enough to attach a 1N4001 diode to each end, anode to J308 side cathode to the Mic jack. (see diagram below).

  4. Add a 1K ohm resistor to the cathode of the 1N4001 diode and wire the opposite end to the rotary switch, connect it to the etch on the back of the switch that does not have a Grey or White wire (Orange or Brown in the Lincoln) on it. Usually the Violet wire (usually Red in the Lincoln).

  5. Cut the Orange and Brown wires from J308 and route them to the rotary switch.

  6. Connect a 1N914 diode across across the Grey and White wires (Brown and Orange in the Lincoln) on the rotary switch. (see diagram below).

  7. Connect the Brown wire, cut from J308, to the White wire (Orange in the Lincoln) on the back of the rotary switch.

  8. Connect the Orange wire, cut from J308, to the Grey wire (Brown in the Lincoln) on the back of the rotary switch.

Note: If the Up / Down buttons work backwards, exchange the Orange and Brown wires.


MOD # 2

Mod #2 is the same principal as Mod #1, But uses a Solid State approach, and does not require rewiring of the Microphone. This Mod also allows for an automatic frequency increase or decrease as long as you hold the button down.

The rotary switch applies 5 volts to activate the Up or Down control of the VFO.The Mic uses ground to activate the 5 Khz step control of the Up or Down buttons.

Using a 4001 CMOS quad 2 input NOR gate, you can create a multivibrator to generate a pulsed output to allow the ëautomaticí function of the mod. The rest of the 4001s gates are used as gated inverters.

When the UP button is pressed it grounds pin 13, causing the pulse train on pin 12 to be outputed to pin 11 through the isolation resistor to the white wire on J307, this will increment the frequency of the selected digit on the HR2510, about 1 digit per pulse as long as the button is held down.

When the DOWN button is pressed it grounds pin 9, causing the pulse train on pin 8 to be outputed to pin 10 through the isolation resistor to the grey wire on J307, this will decrement the frequency of the selected digit on the HR2510, about 1 digit per pulse as long as the button is held down.


Refer to the Diagram below and create the circuit shown. You can use an experimenters perf board from Radio Shack (P/N 276-158A) and there is ample room in the HR2510 to mount it inside.


  1. Connect the brown wire cut from J308 to the input pin 13 on the 4001 CMOS IC.

  2. Connect the orange wire cut from J308 to the input pin 9 on the 4001 CMOS IC.

  3. Connect the output wire from the Isolation resistor on pin 11 of the 4001 CMOS IC to the top trace on the frequency knob. (the white wire).

  4. Connect the output wire from the Isolation resistor on pin 10 of the 4001 CMOS IC to the 2nd trace from the top trace on the frequency knob. (the grey wire).

  5. Connect the power wire to the 5 volt regulator pin 3 (facing the front of the radio, the far right leg of the L78MO5CV, located in the middle of the microprocessor circuit board). [see diagram]

  6. Connect the ground wire to a good circuit ground.(you can use the left rear screw on the microporcessor board mounting).

After installation all the controls should work normally, and when pressing and holding the mic buttons the frequency should slide up or down the band at about 2 increments a second.

If you have any questions, you can E-mail me. Although I have not tried this mod (MOD #2) it is fairly straight forward.

Thanks toVE2XQQ for the mods and schematic.

This modification is read 5518 times.

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Talkback removal
Author: VE2XQQ

MOD #1 - The Relay Approach

One method of Talkback removal is to break the speaker line with a relay.

Parts needed :

12Volt SPDT relay
2 - 1N4148 Diodes
1 - 1N4001 Diode
Several pieces of hookup wire

Jumper the Relay coil - K1 with a 1N4001 Diode - D1. To key the relay you connect one side of the Relay coil (the side with the Cathode of the diode) to IC107 pin 1.(HA17808W)

Cut the Blue wire that goes to pin 1 of the AUX plug on the rear of the radio. (Make sure you leave enough wire to reconnect each end to wires for the relay.) Attach the wire from pin 1 of the AUX plug to the Wiper contact of the Relay- K1. Attach the other half of the Blue wire to the Normally Closed side of the Relay.

(Make sure you leave enough wire to reconnect each end to wires for the relay.)

Cut the Yellow wire from pin 3 of the Mic plug. Jumper the cut Yellow wire with a 1N4148 Diode - D2 (Cathode to the Mic Plug Pin 3) Connect the last 1N 4148 Diode - D3 to the Relay coil, Anode side to the Anode of the Diode - D1 on the coil of the relay.Connect the Cathode to Pin 3 of the Mic plug.(Cathode to Cathode of the two diodes on pin 3 of the Mic plug.)

MOD #2 - The Solid State Approach I

All that is needed is to add a 1N914 Diode from pin 6 of IC103 to the collector of Q125.

Connect the cathode of the diode to pin 6 of IC103, and the anode to the collector (the center pin) of Q125.

MOD #3 - The Solid State Approach II

All that is needed is to add a 1N914 or a 1N4148 Diode connected to a 10k to 100k resistor from pin 6 of IC103 to the Base of Q127.

Connect the anode of the diode to one side of the resistor. Connect the other side of the resistor to pin 6 of IC103, and the cathode to the Base of Q127.

Note: Use a 10k ohm resistor if you only use the internal speaker. Use a 100k ohm resistor if you use an external speaker.

These last 2 MODs remedies the Audio Feedback caused by the Audio Amplifier chip, IC103 (TDA 1905) not being switched over completely from RX to TX when you key the mike. These fixes rebias the switiching transistor to correct this.

Thanks toVE2XQQ for the mods and schematic.

This modification is read 5701 times.

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HR2510 RIT / Clarifier Mods
Author: VE2XQQ

The RIT (Receiver Incremental Tuning) on the HR2510 is a Clarifier control to help ëtune iní usually SSB signals that may be transmitted off of center. The RIT only works on the receiver. The HR2510 does not allow ëslideí on transmit unless its modified. Many people wish to ëOpení the RIT (or Clarifier).

Everyone has a different mod for this one, I will list the ones I know. Basically they are about the same, You need to disconnect the existing voltage from the clarifier (RIT) circuit and add a constant voltage to the clarifier (RIT) control circuit. This voltage needs to be there during transmit.


Find D150 on the main circuit board. With the radio right side up, it will be found in the front right-hand corner of the PCB. Lift or clip one end of this diode.

Find the orange wire comming from the RIT/RF GAIN PCB (PB-120). From there it goes to the main PCB to a 4 wire connector (Yellow/Orange/Red/Brown) located on the left side of the main PCB near the center of the radio. Clip the orange wire from the connector and feed it through to the other side of the radio. Solder it to pin 3 of IC 311. This will be a three-pin voltage regulator located just to the right of the large microprocessor (IC315). The pins on IC 311 are numbered from left to right.

To center the RIT:

Locate the 3 tuning coils on the front left corner of the main PCB. The exreme left coil labeled L116, adjusts USB. The center coil is labeled L118, adjusts LSB. The right coil labeled L117, adjusts CW. There will be some interaction between the coil adjustments so you may need to repeat retuning a few times. I suggest you start with the USB coil and end with the CW coil. The Mod will give you plus or minus 3 Khz slide, the RIT will NOT change the display, but the transmit and receive frequency will track together now.


Cut D150 on the main PCB. Locate the orange wire at the top of the RIT PCB, cut and connect to pin 3 of IC107. This is a 3 pin transistor bolted to the left side of the case next to VR116. Pin 3 is the lead closest to the back of the radio. You now have +/- 5khz slide.


Find the orange wire comming from the RIT/RF GAIN PCB (PB-120). From there it goes to the main PCB to a 4 wire connector (Yellow/Orange/Red/Brown) located on the left side of the main PCB near the center of the radio. Clip the orange wire from the connector. Find the red wire (8 Volts) on the mode switch PCB and solder the orange wire to it.

To Adjust:

  • Set the RIT to center (12 oíclock) Mode switch to AM Frequency to 28.000 Mhz.

  • Connect a Frequency counter to TP306. Adjust L315 for 6.200Mhz

  • Connect a Frequency counter to TP304. Adjust L318 for 38.695Mhz

  • Connect a frequency counter to TP1.

  • Set the Mode switch to USB, adjust L116 for 10.6975Mhz.

  • Set the Mode switch to LSB, adjust L118 for 10.6925Mhz

  • Set the Mode switch to CW, adjust L117 for 10.6950Mhz

  • Check RIT range. It should be +/- 4Khz


Find the orange wire comming from the RIT/RF GAIN PCB (PB-120). From there it goes to the main PCB to a 4 wire connector (Yellow/Orange/Red/Brown) located on the left side of the main PCB near the center of the radio. Clip the orange wire from the connector. Solder the orange wire to Jumper 13 (JP13) +8V constant . Cut D150.

To center the RIT: With the Mode switch to AM, Frequency at 28.000Mhz, RIT at 12 oíclock, connect a frequency counter to TP304, adjust L318 for 38.695Mhz.

HR2600 NOTE:

D150 is for the HR2510, D43 is for the HR2600, also in the HR2600 the wire may be orange or brown. The connector on the main PCB is a 5 wire connector.

Thanks toVE2XQQ for the mod.

This modification is read 5865 times.

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HR2510 Misc. Enhancements
Author: VE2XQQ

Increasing the Receive Audio I

The HR2510 does not have a by-passed emmiter in the audio circuit. To correct this, Add a 4.7uf 16v Electrolytic capacitor across (in Parallel) with R152 (a 560 ohm resistor). This modification will increase the receive audio.

Increasing the Receive Audio II

This mod will increase the AM reception: Replace the AM Detector diodes (D111 & D112) with better Schottky Barrier diodes. You can use ECG 583 or NTE 583 diodes or 1N6263 or equilvalent. (In the HR2600 the diodes are labelled D11 & D12).

Increasing the Receive Audio III

This mod will increase receive strength and dynamic range, resulting in louder, cleaner signals while actually reducing noise levels. All you need to do is to replace the existing IF Amp transistor with a new one which has greater frequency response and lower noise characteristics. Once installed you will need to adjust your ìSî meter for more realistic readings.

  1. Remove diode D101 and Transistor Q101.

  2. Replace Q101 with a ECG or NTE 23.

Note: The new transistor has a different pin out from the original. You will need to reorient the new transistor to work. With the flat side of the transistor facing you and leads pointing down : Exixsting leads of Q101 = 1 2 3 , the replacement ECG or NTE, you will need to cross the first lead to the last = 2 3 1 .

Mute circuit improvement

To Improve the operation of the Mute circuit, remove C139 and R199. These two components are connected to the base of Q117.

Roger Beep Mods

The Roger Beep in the HR2510 is ëUniqueí but kind of wimpy..To modify this, locate R96 (a 2.7 Meg. ohm resistor) Remove and replace with a 100K ohm 1/8 watt resistor. This will increase the amplitude of the beep.

To change the duration (length) of the beep, replace C110 (10uf 16v ) remove and replace with a capacitor at least 50v with more or less capacitance to lengthen or shorten the beep to your preference.

These components are located to the left (facing the front of the radio) of IC 104.

Component location diagram

Adding an external meter to the HR2510

To add a needle type meter all you need to do is connect it to C302 on the Microprocessor.

Thanks toVE2XQQ for the mods and schematic.

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24 MHz Broadband instructions for your HR2510
Author: VE2XQQ

What is chipswitch ?

These instructions are to broadband your radio if you have the 24.000Mhz mod or the ChipSwitch installed.

MOD #1

  1. Take the four screws out of the speaker cover on the radio.

  2. With the radio upside down and the PLL board facing you, Remove the four screws in each corner of the pll board.

  3. Loosen the four screws on the sides of the radio that hold the PLL tray in the radio. Loosen them all the way before they come completely out.

  4. Pull the PLL board out towards you so the bottom of the PLL board is upside down.

  5. Look at the diagram below and locate C304, C326, & C327. At the point where they connect together, you will place 1 leg of a 50V 220pf capacitor (Radio Shack P/N 272-124) and the other leg to Ground of the board.

  6. Check your work and make sure you did not short anything out and that you placed the capacitor in the right place.

  7. Reassemble the PLL board and connect power to the radio.

  8. Connect a watt meter and a dummy load to the antenna jack.

  9. Put the radio on 29.500.Mhz and peak L310 for maximum output power.

  10. Now put the radio on 25.500Mhz and peak L319 for maximim output power.

  11. Reassemble your radio and your ready to go.

MOD #2 A simpler method...

Here is a simpler method of increasing the VCO coverage on the HR2510. If your HR2510 is Chipswitched, but doesn't lock on 12 Meters, this mod will take care of the problem without having to access the underside of the synth PCB.

Remove the four screws from the bottom cover and remove the cover.

On the PLL board locate L307 (TP306).

Install a small ceramic capacitor between the long lead of L307 and ground. Any value between 180 and 220 picofarad (pf) will do. There is a convenient ground loacted just behind L307. this locationis a plate-through hole (it looks like a shiny solder dot showing through the silk screening.)

The set should now lock from 24.800 to 29.900Mhz without further adjustment.

If you have access to a scope, the radio can easily be broadbanded for better performance in this new frequency range. to broadband, monitor the output at J311 and adjust L310 and L319 for equal output at the upper and lower limit of your operating range.

Thanks toVE2XQQ for the mod and schematic.

This modification is read 6257 times.

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HR2510 Alignment Instructions

(Taken from the Uniden Service Manual)

Alignment of P.L.L. and Carrier Oscillator Portion

1. Test equipment required:

DC Power supply (13.8V) Oscilloscope
DC Voltmeter Frequency Counter
Dummy Load (50 Ohm)

2. Preparation for Alignment:

PA SW : Off Mode SW : AM
RIT : Middle Position TX SW : Off

3. Alignment Procedure:

Preset to: Adjustment Remarks
1 Mode : RX, AM
SG : 28MHz
L315 Connect an oscilloscope to TP306.
Adjust L315 For 6.200MHz +/- reading on the oscilloscope.
2 Ditto L318 Connect the oscilloscpe to TP304.
Adjust L318 for 38.695MHz +/- 20Hz reading on the oscilloscope.
3 Mode : RX, AM
SG : 29.6999 MHz
L317 Connect a DC Voltmeter to TP303.
Adjust L317 for 6.5 +/- 0.1V reading on the Dc Voltmeter.
4 Mode : RX, CW
SG : 28 MHz
L117 Connect the oscilloscope to TP1.
Adjust L117 for 10.6950MHz +/- 20Hz reading on the oscilloscope.
5 Mode : RX, LSB L118 Adjust L118 for 10.6925MHz (-40Hz to +0Hz) reading on the oscilloscope)
6 Mode : RX, USB L116 Adjust L116 for 10.6975MHz +/- 20 Hz reading on the oscilloscope.
7 Mode : RX, USB VR111 Connect the oscilloscope to TP5.
Adjust VR111 for 38.6975MHz +/- 20 Hz reading on the oscilloscope

Alignment of Transmitter Portion

1. Test equipment required:

DC Power supply (13.8V) more than 10A
AF S.S.G. AM FM (1kHz, 500Hz and 2400Hz)
RF VTVM Oscilloscope
DC Ammeter RF Power Meter
AF VTVM Dummy Load (50 Ohm)
FM Linear Detector

2. Preparation for Alignment:

VR112 : Clockwise PA SW : Off
VR113 : Counter Clockwise Meter SW : RF
VR103 : Clockwise MicGain SW : Off
SWR/CAL : Middle Position TX SW : Off
Freq. : 28.000 MHz

3. Alignment Procedure:
Preset to: Adjustment Remarks
1 Mode:USB
No Mod.
Remove the B002(PB-100) from the Main PCB.
Connect a DC Ammeter (+) to TP4, (-) to TP3.
Adjust VR112 for 50mA reading on the DC Ammeter.
2 Ditto VR113 Connect a DC Ammeter (+) to TP4, (-) to TP2.
Adjust VR113 for 50 mA reading on DC Ammeter.
3 1mV Mod. L111 Disconnect DC Ammeter. Reinstall the B002 to the Main PCB.
Connect A RF Power meter to the ANT. jack. Connect a RF VTVM, an oscilloscope and a FM Linear Detector across a RF Dummy Load to the RF Power meter.
Adjust L111 for maximum reading on the RF VTVM.
During this step, set the AF oscillator so that the output is less than 20V.
Repeat this two times.
4 30 mV Mod. VR104 Adjust VR104 for 32.5V reading on the RF VTVM.
5 Ditto VR106 Adjust VR106 so that the carrier leakage at USB and LSB becomes minimum and almost equal.
6 Mode: CW
No Mod.
VR103 Connect a SW between Pin 8 and 9 of the ACC connector.
With the SW turned on, adjust VR103 for 21W reading on the Power meter.
7 Mode: AM
No Mod.
VR107 Adjust VR107 for 10W reading on the RF power meter.
8 Ditto VR117 Adjust VR117 so that "9" LCD just lights on.
9 1 kHz, 30mV
VR114 Adjust VR114 to obtain the 85% negative reading on the oscilloscope
10 1kHz, 1mV
VR115 Adjust VR115 so that "9" LCD just lights on.
11 Mode: FM
1kHz, 30mV
VR105 Adjust VR105 for +/- 3kHz deviation reading on the FM Linear Detector
12 Mode: CW
No Mod.
Vol. : Max
VR116 Connect a AF VTVM across a dummy load (8 Ohm) between Pin 1 and Pin 2 of the ACC connector. With the SW turned on, adjust VR116 for 0.4V negative reading on the AF VTVM.

Alignment of Receiver Portion

1. Test equipment required:

AF VTVM DC Power supply (13.8V)
Oscilloscope Dummy Load (50 Ohm)
S.S.G. AM FM (28.000MHz, 1KHz, 30% Mod. and 50 Ohm Impedance)

2. Preparation for Alignment:

NB SW : Off Mode : AM
PA SW : Off Squelch : Min. (Auto SQ Off)
Beep SW : Off RF Gain : MAX
RIT : Middle position

3. Alignment Procedure:
Preset to: Adjustment Remarks
1 L101, L104,
L113, L115,
and L105
Alignment of sensitivity
Adjust coils for maximum reading of the AF VTVM. (During this step, set the S.S.G. attenuator so that the standard output is less than 0.5W (2v/8ohm)).
2 VR102 Alignment of Squelch
Set th output of the S.S.G. to 66dB +/- 2dB and squelch to maximum. Adjust VR102 so that squelch just breaks.
3 VR101 Alignment of S-Meter
Set the output of the S.S.G. to 46dB, no modulation.
Adjust VR101 so that "9" LCD just lights on.
4 Mode : FM
S.S.G. : 1mV
(1.5kHz Dev.)
L401 Adjust L401 for maximum reading on AF VTVM.
5 Mode : AM
Noise GEN.
to the ANT Jack.
L203 Adjust L203 for minimum reading on the AF VTVM.
(Noise GEN. OUTPUT : 50Hz SQ Wave 2Vp-p)

Alignment layout

Refer to the HR2510 Alignment instructions
(The colors correspond to the adjustment procedure)

Thanks toVE2XQQ for the info and schematic.

This modification is read 6437 times.

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