Realistic LAB-430 - Dead - Power Supply?

[Johnny_Law]

First of all I can't find a repair / service manual anywhere for this thing. But it's similar to a beaten and broken LAB-450 parts unit I have, so I can scavenge parts from that if I have to, I think.

The problem is that it's totally dead. Looking at the power source, I'm getting a good 120VAC in the power cord, but only about 0.6V on the other side of this blue cap into the transformer - and nothing out of the transformer.

Forgive me for the stupid question, but it seems like the cap is bad? How do I read these markings to find a suitable replacement?

Thanks much.

 

[Johnny_Law]

Woops, fixed the pic.

Also, I found the manual for the LAB-400 which lists a similar cap as metalized mylar 0.0022uF / 125V.

However, measuring the voltage across the cap in both my good LAB-450 and this LAB-430, they are both around 125V.

 

[Johnny_Law]

Alright so I confirmed that 17VDC should be output to the motor. (This thread has a circuit diagram with reference values.) I am getting no output whatsoever so I'm trying to trace it backwards.

I have two theories right now: one, the rectified bridge IC is bad. I am not getting much voltage output from it whatsoever. Or two, the transformer is bad. I am getting around ~1VAC across the output winding.

Here's the rectifier bridge IC (to the right of the black capacitor):

And here's a birdseye view of the entire power supply:

Any advice on what / how to test these theories?

 

[tubewade]

Greetings!

Where do the two tan wires go? It appears that the capacitor is across those leads which causes me to believe they go the power switch. If this is so and you show 125 vac across those leads all the time then the power switch is bad. That capacitor, if used in the way I believe it is, serves to eliminate a "pop" when the switch is operated. Otherwise it has no effect on the operation of the turntable or power to the transformer. In the circuit diagram on the other thread the switch would be S101 or S103 and your capacitor is C101, and the value is .01uF.

 

[Johnny_Law]

Thanks! Actually here we have a great example of me needing to do a little more snooping before deciding what the problem is!

Turns out, this has a roller switch that connects the power to the transformer only when the tone arm is out over the platter. I traced the linkage back and found out that the tone arm base's set screw to the shaft had broken the plastic and wasn't getting any traction! I found that when I connected the switch manually, the power supply works great!

So here it is broken - it's getting a super glue treatment now and will get a zip tie as well which should hold the set screw with enough force to operate correctly.

Overview of the linkage:

The switch and linkage to the tone arm:

And the culprit: