PRESIDENT LINCOLN User manual

PRESIDENT LINCOLN (HR 2510) MODS
by Roger Perales
http://www.gj.net/~perales
Conversion of this text from html format to PDF by Frank Tomeš
http://come.to/329RC106
Radio Modification Information
This site is provided for the sharing of information for educational purposes only. The use of this
information may void your radios warranty, The modification of your radio may make its use illegal.
The owners of this page DO NOT warranty any of this information, nor accept any responsibility of
how you use its content.
www.president.com
If you have any Questions or Comments, you can E-Mail me at [email protected]
Jestli máte njaké dotazy nebo pipomínky, pošlete mi e-mail na tom[email protected]
nebo na f.tom[email protected]

Table of Contents
To convert the HR2510 to 11 Meter operation: .......................................................................................4
To convert the Lincoln to 11 Meter operation: .......................................................................................5
HR2510 Modification for increased MicGain ..........................................................................................6
President or Uniden HR-2510 Variable Power Modification .................................................................7
Increasing the power output for the HR2510...........................................................................................8
Modification of the HR2510 Mic buttons to operate the VFO .............................................................10
MOD # 1 ........................................................................................................................................10
MOD # 2 ........................................................................................................................................11
Talkback Removal.....................................................................................................................................13
MOD #1 - The Relay Approach ..................................................................................................13
MOD #2 - The Solid State Approach I .......................................................................................14
MOD #3 - The Solid State Approach II ......................................................................................15
HR2510 RIT / Clarifier Mods .................................................................................................................16
RIT MOD I ...................................................................................................................................16
RIT MOD II ..................................................................................................................................16
RIT MOD III ................................................................................................................................16
RIT MOD IV .................................................................................................................................17
HR2510 Misc. Enhancements. .................................................................................................................18
Increasing the Receive Audio I ....................................................................................................18
Increasing the Receive Audio II ..................................................................................................18
Increasing the Receive Audio III ................................................................................................18
Mute circuit improvement ...........................................................................................................18
Roger Beep Mods ..........................................................................................................................18
Adding an external meter to the HR2510 ..................................................................................19

If you are really interested, I suggest trying the CHIPSWITCH. .......................................................20
24 MHZ Broadband instructions for your HR2510 ..............................................................................21
MOD #1 .........................................................................................................................................21
MOD #2 A simpler method... .......................................................................................................22
HR2510 Alignment Instructions - (Taken from the Uniden Service Manual) ...................................23
Alignment of P.L.L. and Carrier Oscillator Portion .................................................................23
Alignment of Transmitter Portion ..............................................................................................24
Alignment of Receiver Portion ....................................................................................................26
HR2510 Alignment and Test Point Layout ............................................................................................27
Synthesizer / Microprocessor / PLL PCB ...................................................................................27
Main PCB.......................................................................................................................................27
HR2510 Circuit Block Diagram...............................................................................................................29
Microphone wiring....................................................................................................................................29
Some interesting e-mails...........................................................................................................................31
Subject: Re: Kterou stanici vybrat ? ..................................................................................31
Subject: Re: Lincoln mods homepage ................................................................................32
Subject: Mirror.....................................................................................................................32

4
To convert the HR2510 to 11 Meter operation:
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)

5
To convert the Lincoln to 11 Meter operation:
Remove the cover on the speaker side of the radio..
Locate the the Microprocessor on the SYNTH PCB.
Tie a jumper wire from the thru plate via hole at the end of the trace the bare end of the 10K ohm
Resistor. (see diagram) or connect pins 34 & 35 together..

6
HR2510 Modification for increased MicGain
This mod will increase the AM modulation.
The AM modulation adjustment is VR114, which is marked >AMC=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 >stock=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.
Send E-Mail to [e-mail]

7
President or Uniden HR-2510 Variable Power Modification
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.

8
Increasing the power output for the HR2510
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.]
4). Replace Q132 with an MRF 497. ( Be sure to use heat sink compound.)
5). Remove C132. (no replacement)
6) Remove C112 & C116.
7). Replace C112 with an 82pf capacitor, But put the new Capacitor on the bottom of the PC board.
8). 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
9). 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.

9
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. ]
10). 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
11). 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.
12). 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 >73 magazine
of November 1989 on page 76, Although I have never been able to find a copy to verify it.

10
Modification of the HR2510 Mic buttons to operate the VFO
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 >5 volts=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).
Instructions:
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.