Late '60s Sears Silvertone Hi-fi Problems

Hello everyone. I've tinkered with radios and hi-fis for years, but most of my successes have been with tube equipment. I came across my current project for $5.00 at a trailer park sale, felt sorry for it, and dragged it home to join the rest. It's a smaller, Spanish style Sears Silvertone solid state am-fm-turntable unit, radio chassis # 628-64430. I haven't found a date on it, but going by the style I'd say it was from the late '60s or early '70s. The main reason I picked it up was the turntable; it has pitch control, adjustable counter weight on the tone arm, auto and single play spindles, a brush that wipes the needle off every time it sets down...neat stuff that you don't usually see. Anyhow, the turntable works fine and only needs some cleaning and lubrication (and probably a new needle). But I've got no radio. I tried searching for any stations at high volume and noticed that the unit started 'motor-boating' so I replaced one of the old electrolytic caps on the radio board. No more motor-boat, but only a couple very weak fm stations and still absolutely no am. I've checked for loose wires/connectors, burnt components, etc. to no avail. I'm thinking maybe there are some bad transistors but I'm not sure where to start. There is a transistor schematic inside the cabinet, so I know where each one is and what it does. Does anybody have some advice on what I should do next or which transistor(s) might be the culprit? I'd like to know I was replacing bad components instead of just throwing parts at the poor thing. Thanks in advance for any information on this unit.

Why replace just one electrolytic? I would replace ALL of them. They're probably 40+ years old and they're usually the first things that act up. That could possibly cure all the issues. Fresh caps can work wonders...LOL. I've had two consoles with dead FM/AM and new electrolytics brought them back to life. Less than $5.00 for the fix, and everything seems to work okay, but I didn't check the resistors. It's on the to-do list.

I've checked the old caps out of curiousity and It amazes me how these units can be so forgiving. I don't think tube equipment may be as tolerant, but I've seen caps that wouldn't even measure on a meter, or they went way off the scale, and still the stereo worked. --BB


Bobby Basham
Tucson, Arizona

Thanks for the info. I was trying to work with what parts I had instead of ordering some. So I'm putting in a capacitor order to Parts Express. I'll get caps for a couple other projects too (Packard Bell console and Grunow radio). I'll let you know what happens.

Hey geetee,

I'm just an amateur working on my old stuff, and don't get as deep as some of the more qualified folks on here. But in my cases, just replacing those electrolytics did the trick.

I like Parts Express and ordered alot of speakers from them. Hey Folks, that site is good for those DIY's for speaker building projects, surround sound/entertainment installations. I think their prices are reasonable and they always have sales. It's been a few years, but I think I ordered semiconductors from Mouser Electronics. The sales reps are real nice (before I went online), and their prices are good.

Yes, please keep us posted on your progress. We love hearing about these projects and we all learn from them, at least I do. After sitting at a desk/computer typing redundant crap all day, it's good to have questions and issues to stimulate some brain cells, and I always look forward to all the answers that stream in. Bless this Board.--BB


Bobby Basham
Tucson, Arizona

Hello again. Well, I replaced the two can capacitors on the amplifier board and the record player sounds even better, but still no radio to speak of. I can poorly pick up maybe six FM stations between 100 and 106 but they're choppy sounding. And no AM whatsoever. I've connected both the internal antenna and our outdoor external with no change. Any suggestions as to what I should start messing with next? Thanks in advance...

My question again...

Did you replace ALL the electrolytics? They are scattered through different sections of the board, and there should be a section dedicated to the radio section. You probably didn't have to go to the can caps first. Take a good look at that chassis. You shouldn't have to go out all the way to the outside power pole to find a bad outlet in your house. Narrow it down and it may save you alot of labor. --BB

Bobby Basham
Tucson, Arizona

My customers wouldn't want me "messing" with their stuff...
They expect a proper restoration for their money, and that is what they deserve and get.

Take the thing to a reputable service shop and save yourself the aggrevation of "tinkering" around with it.

There's a right way and a wrong way to go about it.

Unhealthy as it may sound, I like tinkering with old electronics. Well, just about anything that's out of warranty and not working. I usually go for the real basket cases since I don't feel like I'm ruining anything if things go horribly wrong. And I'm always learning something new if all else fails. I was given a Fisher 500-B tube receiver a few years back and except for re-tubing it (someone had removed all but one 12AX7 of the originals), I wouldn't trust my meagre skills to go ripping into it. It does work but I'm saving up to let an authorized Fisher outfit do the restoration...though having to ship it anywhere gives me nightmares.
I appreciate any info you all have and thank you for bearing with my questions. I'm on "furlough" from work right now (all us employess of this outfit think that this will soon be followed by "laid-off"), so I'm trying to keep busy and amuse myself. Next on the list is a '50s Zenith radio-record player that was given to a thrift store with the whole chassis loose inside (arrrgh!).

I know this is old news; but, I agree that every electrolytic cap should be replaced. I recently repaired two RCA Victor solid state consoles for two different people who had been trying to find someone to repair them for years. You know, most shops don't want to fix anything over 10 years old. Both units needed a full electrolytic recap in order to work properly. These stereo's were loaded with those little black electrolytic caps that where labeled WHALE or CALLINS and every one of them were either open or measured way out of spec.

Those Silvertone stereo's were built by Warwick Electronics and those used the same inferior caps. Even back in the early '90's, I was running into these with bad caps. Some models had some large, orange colored cardboard tubular electrolytic caps in the power supply and output stage and, back then, these were the main troublemakers in those sets.

I don't mess around replacing a cap here or there. I replace all paper and electrolytics and if it is a radio I make sure I put the caps in the same location I found them to avoid any interference.

If you have no radio, it might simply mean that you have no antenna. Many of those came with accessory antennas you connected to the back of the set.