HR2600.1


  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.

73'S AND ENJOY THE UNIDEN!

CRAIG/N7ETV @ WB6MQM
LAS VEGAS, NEVADA. 89121

addendum:

this mod files talks abount changing some caps (namely c99 4.7uf) to .01 uf
i tired this on my 2510 and it did speed up Tx to Rx delay real well but...
it messed up CW at speeds 0-17 wpm.... made it chopy... but worked ok
at high speeds.... i tacked on a .1uf cap to c99 (the .01uf the mod called for)
this fixed up CW and seems to still work good for packet.)
so you might want to append this info to that mod file.
de kc6tdh brad @ n6reb.#nocal
also im looking for a hr2510 mod file that will let me 'unmod' the xrit
back to a 'rit' if you know of any info on this.... thanks brad