Repair power - Silvertone cabinet

[GStewart]

I have a 1960s Silvertone cabinet with turntable, radio and reel-to-reel recorder which I got from a moving sale last fall. It worked perfectly until today when there is suddenly no power.

Exterior

• GStewart
• Mar 11, 2017

Radio

• GStewart
• Mar 11, 2017

Chassis number C817-50036:

There are two paper slips with chassis numbers as well, perhaps for the turntable and reel to reel? They are:
1487208 and 1474553 - no periods or dashes in those numbers.

Chassis Number 2

• GStewart
• Mar 11, 2017

Chassis Number 3

• GStewart
• Mar 11, 2017

I have zero experience but would love to get this back up and running, as the sound is beautiful. It's almost the same as the cabinet we had growing up so that's another reason to keep it alive. Any info or help is much appreciated!

Back Panel2

• GStewart
• Mar 11, 2017

Interior

• GStewart
• Mar 11, 2017

Power Panel External

• GStewart
• Mar 11, 2017

Power Panel Interior

• GStewart
• Mar 11, 2017

I don't have a schematic, just this connection map stapled inside:

Connection Map

• GStewart
• Mar 11, 2017

 

[rave0035]

When you say "no power", describe what you mean.

Is that blue thingamabob a power indicator? If so, does it light?
Does the turntable still function, or is that dead also?
Do you get any kind of audio on any of the channels?
Any hum from the speakers?
Did you notice any smoke or funny smells when the unit stopped working? Did it stop abruptly?
Is it plugged in now? If so, I'd unplug it.

Mike

 

[GStewart]

Thanks for the quick reply.

No power of any kind to any component, just inert. No smoke or smells, it is currently unplugged. No hum, spark, crackle or anything from the speakers.

A few days ago I connected a bluetooth adapter thingy via 2 rca plugs into the tape deck record inputs at the back. Would that have killed it? The bluetooth device has its own power source plugged into a separate outlet and was just supplying audio in. We used it twice with no issues.

 

[gadget73]

Did you try pushing the reset button? Its a circuit breaker, meant to trip if something goes wrong.

 

[GStewart]

Yes, to no effect. I always start with the simple stuff - is it plugged in? etc.

 

[gadget73]

Do you have a multimeter you're comfortable using? Could be something simple, maybe more involved. No power at all is usually something fairly obvious. A bad breaker, fuse, switch, broken connection, etc. There are only so many things honestly.

 

[GStewart]

As I said, I have no experience at all. Looking at the interior and the back of the power panel, nothing seems obviously broken or disconnected.

Interior

• GStewart
• Mar 11, 2017

Power Panel Interior

• GStewart
• Mar 11, 2017

I can borrow a multimeter and try not to electrocute myself. Do I start with the plug itself? It's a 50-year old cable, it might have just worn out. Otherwise, I don't know where/what to test.

 

[rave0035]

Yes my first thought here would be to suspect that circuit breaker.

Set your borrowed multimeter to read AC volts. But the red lead (carefully)! on the red terminal behind the power plug, and black to black. Don't slip, and use the little clippy aligators if you've got them. The meter should tell you that there's about 117v there.

Then move on to the back of the breaker.... from the photos, it looks like you'd leave the black lead in place and touch your red probe to the un-insulated wire going to the back of the breaker. Got voltage? If so, then check black to blue on top of the breaker. Still got voltage there? If so, the breaker is functioning correctly and the trouble lies downstream.

Mike

 

[gadget73]

Try plugging a table lamp into that outlet on the back. If that works, the power cord is OK. You can move on to checking the breaker at that point.

 

[GStewart]

Here's a pic of the power cord, it connects via prongs in the back rather than a standard plug:

Power Cord

• GStewart
• Mar 12, 2017

I'm off to look up how to use a multimeter. As I said above, I think the first thing I should check is that there's power in the holes seen in this picture.

FYI, the outlet itself is working.

 

[rave0035]

To Gadget's point, if the auxiliary outlet on the back of the unit works, it means the cord is OK and you've got 120v up to the circuit breaker. You will need a multimeter to find any faults beyond that.

Mike

 

[GStewart]

Try plugging a table lamp into that outlet on the back. If that works, the power cord is OK. You can move on to checking the breaker at that point.

I misread this message yesterday - I just tried it and the aux outlet does work.

Can you please confirm, is the circuit breaker the part wrapped in yellow?

 

[rave0035]

It's the deal with the red 'reset' button. It looks like the output wire is blue. You'll want to measure AC volts across the blue terminal on the back of the breaker and the black terminal on the back of either AC plug.

Mike

 

[gadget73]

Those are what are known as "cheater cords". You can remove that clip and pull the cord loose from the back panel to allow for testing with power to the amp. Just be careful, the whole point of clipping the cord to the back was to make it so you can't do that and get yourself hurt.

 

[GStewart]

First, thanks everyone for your help - I think the problem is with the breaker. I followed Mike's directions above:

1. 119V (actually anywhere from 119 to 121) measured from A to B
2. Same from A to C
3. Nothing from A to D. I tried all around area D to no effect. Should I get a reading from any of the soldered area or just exposed wires?

I really hope that's it, because from there the wires go off inside before there's another connection, and I don't want to take the thing apart.

So, assuming the breaker is the problem, is this a part I can find a replacement for?

 

[gadget73]

yeah sounds like the breaker. Any point that looks like metal around the D terminal should give you a reading.

If you can see an amp rating on the side of it somewhere, that would help ID a replacement. Worst case, a fuse holder and a fuse can be installed.

 

[GStewart]

Worst case, a fuse holder and a fuse can be installed.

To remove it, do I just snip the wires connected at points C and D? After unplugging the stereo, is there any residual charge in the breaker?

Can you help me understand the circuit as well; as I see it, the voltage goes from A&B directly to the aux outlet, then to the breaker through that single wire at C. Another set of red and black wires joins the blue wires to power the rest of the system. What is the function of the blue wires if power is already going through the red and black?

 

[gadget73]

You may be able to pull it out enough to read any markings without unhooking the wires. If not, snip C and D and pull it out. Its probably got twist lock tabs on the button side, just bend them straight and it will let go.

It won't hold any charge in the breaker.

The blue wires are probably what actually feeds power into the amp since they go through the breaker. No idea what the red wire goes to inside, maybe the turntable.

 

[GStewart]

Thanks, I'll try that. I still don't understand the circuit though - supposing the blue wires do power the amp, the only voltage connection from the power outlet is that one wire at C? The breaker isn't attached anywhere else.

Here is the breaker - the only information on here is "79F 010-2 F7"

 

[rave0035]

The breaker acts like a switch - it only allows current to flow when it's 'closed' and the protection circuit is operating normally. When too high of a current passes, it trips 'open' and breaks the circuit. We want to determine the proper current limit for this circuit so we can replace this breaker with a similarly rated fuse to avoid damaging your equipment.

The black wire is likely neutral.

On the back of the unit, are there any notes about wattage or power consumption? Do you own a Kill-A-Watt? I think it would be smart to try a fuse in place of this breaker before we bypass it, in case there's something out of sorts in the unit. That may, as we say, 'let the magic smoke out'.

Mike