Sears Silvertone table radio, model 5021

[William]

Silvertone radio update:

Right this minute it is working, but I have had that scenario more than once over the past month plus.

This past weekend totally redid a bunch of solder joints around the two audio output tubes. Plugged it in and it took off and I played it for 5 hours straight without a hitch. Next day I turned it on and it played just fine. Finally! I should not have said that. I decided to carry it upstairs to the kitchen so I could play it for a couple of days just to make sure. Got it upstairs, plugged it in, ZIP, back to the same old thing. Grr... Back to the basement, plugged it in and it worked just fine. Double Grr...

At that point I grabbed my plastic poker thing and started to push, wiggle and move the PC board. Nothing I did made it act up, it played just fine for several hours.

Next day I went to the basement, turned it on and it was acting up. Again, I took my plastic thing and started to do my usual to see if I could make it do something positive. As I was wiggling, pushing and beating on things I noticed a faint crackle when I pushed the long wire that goes to one of the wire wound resistors. It sits right beside one of the output tubes. As I moved this wire I could make the radio play. Moving it back to the original position it would fade back to not working. Instead of just trying to re-solder it I decided to replace it, kind of a just because thing. I called Mike, he had one, 300 ohm 5 watt. I drove over and picked it up, installed it, and right now it is playing. Been down that road before but keeping my fingers crossed that, dare I say it, it is finally fixed.

Stay tuned!

Bill

[electra225]

We'll keep a good thought that you got it this time. You should be sure to tell Mike how much you appreciate him being there for you. I sure wish he was closer to me......

[William]

I tell him every time I go there, after all he is officially retired and the store is closed. He has his favorites and I am so thankful I am one of them.

Bill

[electra225]

Was the 300 ohm, 5-watt resistor in the power supply?

DUH....If I wasn't too lazy to look at the schematic, I would see that this resistor is in the heater string. R38 is it's schematic symbol. How would that resistor create a hum? .....

[William]

Yes it is, and it was more of a hum/buzz/crackle/static sound. I also replaced two capacitors that are part of that circuit.

Bill

[danrclem]

Hopefully that's it and you won't have any more problems with it.

[William]

Another update:

Almost, and then not! I really thought I had it, played on the bench for 4 days. I put it back in the cabinet and it played for a full day. I felt brave, I put the back on and it played all Sunday afternoon. I turned it on Monday morning and it played until I turned it off when I left to run errands. This morning, Tuesday, I turned it on and it just laughed at me. Played me for a sucker. Brought it back to the shop, plugged it in, turned it on, and it still laughed at me. Took the back off, turned it on and it played just fine. I took my plastic thingy and pushed, tapped, rapped, wiggled everything I could think of, I even beat the top of the cabinet and picked it up about 6 inched and let it drop. Nope, just kept on playing. It is still in the cabinet, back off and I will try it again in the morning. I am totally baffled, stumped, and perplexed.

Bill

[electra225]

What if you try to "fool" it into thinking the back was on when it is not? Use your cheater cord, then wiggle it up and down to see if the back might be putting SOMETHING (?!!?) into a bind. You might also take the clip off the Interlock, then hog out the hole around the plug so the power cord floats instead of being rigidly attached to the back. That might make "the radio gods" think the back was off when it was actually in place. Wow! This one is a tough one.......Good luck.....

[William]

I thought about pulling the interlock off the back and then just leaving the back off but I am not sure that will help, I am now thinking I have an intermittent component. Which one, I have no idea. As abusive as I have been to the radio and PC board it should act up, NOPE, it will either stay acting up or when working it will still keep working. Back to the drawing board.

Bill

[electra225]

Leaving the back off a hot chassis set may raise safety concerns. This is an AM-FM set. Have you considered SMD? Does the set act up on both bands? You may have silver migration in an IF can. SMD stands for Silver Mica Disease, nomenclature for the condition where the silver mica capacitors in IF cans start shorting B+ to the signal. Typically a crashing, thunder-like noise, it can also manifest itself in intermittent noises like you are experiencing. Difficult to diagnose (for me at least) and even worse to repair. It typically only happens in one band, the other band will work well usually, but it can affect both bands if a common IF can is involved. Repair involves taking an IF can out of the PCB, taking it apart, removing the suspected mica cap, putting it all back together so it will work, then adding caps of guessed, but still correct, value so the IF can will tune. A radio with a PCB and SMD is a shelf queen as far as I'm concerned. I wouldn't attempt that repair with my eyesight and dexterity like they are. Good luck....

[William]

Thank you for the suggestion, I guess anything is possible. When the "noise" kicks in the radio is still playing behind the "noise". I can turn the tuning knob and change stations, nothing changes as far as the tuner part of the radio is concerned. I have not tried AM, poor reception in the basement especially with the florescent lights on.

Bill