Working on the subject, and have replaced all Electrolytic's, but the oscillator isn't working (2nd radio test). I verified voltages at the elements of both the mixer and oscillator Transistors, and continuity of each winding of coil L2, and all are well within spec. The only audio output is a low hiss.

Hi fifties,

I would place another radio near the one your working on and see if you can hear the osc running as you tune the radio.
Also check you IF by injecting a 455 Khz signal near the high side of your tuning capacitor or just before your 1st IF amplifier to see if your IF is working.

Frank

Thx for the input, Frank. I've actually already done both exercises; "2nd radio test", and I've injected a 455 Kc tone to the base and collector elements of the first and second IF amp Transistors, which came through the set's speaker strong. Actually the IF test wasn't really necessary, since the problem exists before they would get signal.

C8,9,10 ?

RRM

Retired Radio Man had a good point, it could also be any one the caps in the Osc circuit including C7 which couples the Osc signal to the emitter of the mixer.

Frank

Last night I also thought maybe C7, C8, and C9 should be checked after looking at it.

I would try injecting a low level 455 kHz signal at test point "2" shown on the schematic using a small capacitor for DC isolation. This would verify that transistor "X1" is working since you already know that the IF amps are working.

Dave

Thx for the input, gentlemen; I'll test as suggested and report back.

It's fixed.

I did as Dave suggested, and injected a 455 KC tone to the base of the mixer. The tone came through, and in twirling the dial around, the 1040 KC signal from my SSTrans also came through. I've been to this rodeo before, so I D/C and then reconnected the antenna coil leads, and proceeded to re-flow front end solder connections, and was able to get it to then receive a few stations, but at low volume. Distant ones came in low, stronger locals were garbled. The osc coil slug was also out of it's best position.

Connecting a small amp to ground and the high side of the VC produced normal clear signal on all stations through it, so after verifying the voltages in the audio stage, I then re-flowed solder landings, and got the radio normalized.
I did RF and IF alignments per the SAM's instructions, and the radio now receives from 540 to 1670 kilocycles, and with room filling volume on the locals. It even picked up a station in Fresno, about 200 miles north, during daylight, and another one in San Diego, about the same distance south of here.

I did this repair for a long time forum member, and I'm sure he'll be pleased.

Thanks for everyone's input. I always get sufficient help on this board to fix any set that I've ever asked about.

Congratulations! It's been a while since I've worked on an 888 but I now recall that some of the solder connections on the early PC boards used in these sets were a problem.

Dave

Big thank you Rich, this is a keeper and you know I don't really have a collection anymore.

Glad you got it goin' old fella !

Amazed that many solder connections were bad---did they look okay ? I have seen sets where the component leads themselves oxidized on the surface within the solder creating a resistive or open connection---wonder if that was happening ?

John

That's what had happened on my 888's and also other radios with early generation PC boards.

Dave

"Old fella" - you know how to make a guy feel good, lol! This is a case where you can't tell by looks. The 60 year old solder was sort of dulled down, and grey-ish in color. The only recipe here is to heat every landing until you've done some good.

Hey Richard,

Most of us do start getting a little dull & gray-ish around 60 ! I'm right at the doorstep and can speak from experience... Unfortunately, at that point heated landings only burn your feet...

Sorry---just needed to kid a bit...

John