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F5PBG > MODS 15.01.99 12:14l 91 Lines 4313 Bytes #999 (0) @ WW
BID : 36964_F5PBG
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Subj: UNIDEN HR2600
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Sent: 990109/2005Z @:F5PBG.FBRE.FRA.EU #:36964 [Brest] FBB5.15c $:36964_F5PBG
From: F5PBG@F5PBG.FBRE.FRA.EU
To : MODS@WW
From INTERNET :
UNIDEN HR2600 MODS & INFO
A reliable source recently informed me that the new Uniden HR-2600 10M. rig
may be modified for "expanded" frequency coverage using the same technique as
is done for it's predecessor, the HR-2510. (Pins 34 & 35 of the cpu lifted
from ground and tied to vcc/5v via a 10K resistor on the foil side of the pcb)
This area of the board is sealed in epoxy and very careful work with a x-acto
knife is required or you will lift the traces off the board along with the
epoxy. Freq coverage will be the same as for the 2510.
**********************************************
AFTER HOOKING UP MY HR-2600 TO MY PK-232, I FOUND I HAD SOME PROBLEMS USING
IT IN AMTOR. SINCE I LOVE TO MODIFY AND "FIX" RIGS, I GRABBED MY TEST
EQUIPMENT AND SET OUT TO FIND OUT WHY THERE WAS A LONG SWITCH-OVER DELAY TIME.
AFTER A FEW MINUTES, I FOUND OUT THAT THE RECIEVER WAS COMMING UP OK. IT WAS
THE MUTE CIRCUT THAT WAS SLOW. I FOUND TWO CAPACITORS THAT WERE RESPONSIBLE
FOR THE DELAY IN THE MUTE CIRCUT.
TO FIX THE PROBLEM, CHANGE OUT C74 AND C99 (BOTH ARE 4.7uf @ 50VDC) WITH .01uf
DISC CAPACITORS WITH A VOLTAGE RATING GREATER THAN 15VDC. THESE CAPACITORS
ARE
ALSO FOUND IN THE HR-2510 AS WELL. THESE SEEM TO BE C139 AND C99 IN THE
HR-2510
IF MY COPY IS RIGHT.
THESE CAPACITORS ARE LOCATED NEXT TO THE AUDIO OUTPUT IC (TDA1905) IN THE
RADIO. THIS I.C. IS LISTED AS IC2 IN THE HR-2600 AND IC103 IN THE HR-2510.
I ALSO FOUND THE S/RF METER TO BE VERY SLOW IN MY RIG. I FIXED THIS BY
CHANGING
C302 ON THE CONTROL UNIT (LOCATED NEXT TO J304) TO A .01uf DISC CAPACITOR
ALSO.
THIS CAPACITOR IS ALSO IN THE HR-2510.
AFTER THESE MODIFICATIONS, I HAD NO MORE PROBLEMS MAKING ANY CONNECTS IN ANY
MODE.
************************************************
Subject: Uniden HR2600 on VHF/UHF
I recently purchased a Uniden HR2600 and a Microwave Modules MMT 144/28
2-meter linear transverter and got both interfaced and working well.
The HR2600 has an output power of 25 watts PEP on SSB, CW and 10 watts on
AM and FM. The transverter requires only 0.25 to 25 mW of 28 MHz drive for
proper operation. In an effort to reduce the HR2600 output level to the
level required by the transverter, I removed PB-100, a small double-sided
copper coated circuit board located under the top cover that supplies +Vcc
to the driver and final amplifier stages. I then soldered a jumper between
TP2 and TP4, the outermost prongs that hold PB-100 in place.
This action provides the HR2600 driver with full +Vcc, but removes +Vcc
from the MRF 477 final power amplifier. There is more than enough driver
energy fed through the final to excite the transverter in this configuration.
I've received good signal and audio reports from all the locals when using
the transverter and the HR2600 with this simple modification. I believe this
modification could make the HR2600 useable with other transverters as well.
===========================
With some ham stores closing out the Uniden HR2600 10 Meter all-mode mobile
transceiver, a lot of hams are interested in doing the High-Power Mod which
was originally written up in one of the ham magazines and then later re-
written for a simpler improved version. While it is true that the driver and
final in the HR2600 is the same as the HR2510 and the Radio Shack HTX100, the
circuitry of the driver in the HR2600 is different. If you order the MRF497
Final Transistor from RF Parts, they will send you the mod sheet for the
HR2510. If you perform the driver circuitry mod in the 2510 mod sheet, you
will modify the driver right back to the 2510 circuit. In other words, the
driver of the HR2600 is already setup to punch the MRF497 to full output!
So ignore the part of the mod concerned with changing the circuit around the
driver (Q134 on the mod sheet, but called Q31 in the HR2600). Remove and
replace the final power amp (MRF477) with the MRF479. To adjust Collector
Current use same (80ma) level, but the pot is VR14 in the HR2600. To adjust
driver current use pot VR13 in the 2600 and set to 50 ma. Use pot VR8 to set
AM power output to about 13 watts. To set the SSB output, it is best to use a
directional coupler and a scope or else a station monitor, and set the level
as high as it will go
End
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