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President Washington low mod & bad rx

Z-MAN 369

Active Member
Dec 21, 2012
148
27
28
I just picked up a Pres. Wash. 858 4-pin relic in good shape on a trade, has var. power and does almost 20w. Problem(s) is the mod is low, VR is turned up and mic gain all the way up, tested with an M6B & Tup-9.....should be screamin but the s-meter barely moves unless im whistling in it. 2nd issue is on the recieve or horrible rx. My locals signals are where they should be but garbled up and cookie monsterish (hard to tell who's who kinda) and the needle falls flat, not a squelch but kinda similiar.....bad rx. On SSB rx/tx is excellent, s-meter swings great and rx is great.....I know an old 30yr radio should be re-capped but i really dont want to do every single one....do i? Ive read about the old relay box these old radios have, i will open the clear plastic case carefully and clean the contacts with a match book striker or womens nail file carefully. I will also clean all the controls too with contact cleaner. Any advice is welcome on this old relic.
 

I think you kind of know what the problem is, you just want to avoid having to do all the little buggers..:D
 
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mark them as Robb said and also change 4 or 5 and make sure the radio is still working. this way you know if one of the new ones is in the right way and working. easier to trouble shoot 4 or 5 at a time instead of putting all of them in and find something has happened and not knowing where to look.
 
The caps that I found bad in CB radios never had a single bulge on top of any of them. There were a few caps that were literally shorted out, showing 1/4 ohm resistance. Those kind of bad caps will put a kibosh on any radio functioning. But a number of caps replaced also showed to be way out of tolerance too. You may well find both kinds in any old radio; nature of the beast.

I have replaced many switching power supply caps there were bulging - though . . .
 
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Zman -

These guy who think recapping will cure everything are just tech wannabees. If it's ok on ssb,then we need to look at the circuitry that is for am only. If it's garbled on am receive, does it have a clarifier mod ? If it does, unmod it. In any case, do an alignment, and check again. This should fix the receive problem. For am tx, check the am power regulator (tr 25 and 26). If it's ok, check to see if someone installed a so-called npc mod. If so, remove it. Then do an xmit alignment and see what you got. If there are still probs, we can go from there. good luck, 73s.

-399
 
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Zman do you have the service manual for this radio? it is in Sam's 128 book. you can use the trc-458 manual Robb posted in the manual section
 
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Thanks everybody for the tips, i will try the few you guys pointed out. If you looked at all the old caps in this radio, you would throw up, lol. Thanks for all the advice!
 
President Washington low modulation and recieve

I have seen a few of the 858 boards like the Washington have these symptoms that turned out to be the audio IC. Might be a good starting place...
Keith
KC5QMC
 
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