Repair ZP120

I think that is the vbias cap to the integrated pwm chip. Not common but happens.
2 different circuits from the diodes you showed earlier. Another layer of the onion..

First thing I checked was the fuse but that's still fine. Out here we have 230VAC 🆒
Need to check for a bulb, these things are getting hard to find with LED taking over and thr old bulbs no longer on sale.
So far I see no shorts. I just ordered all the parts, including 2x 1000uF. They seem a bit swollen too. I will report back once I have replaced the parts. That will be 2019 for sure 🙂

OK cool, the bulb is worth the work to get running, will be helpful for anything off line you test.
I have had a hell of a time getting those 1000uf caps in the right case sive. A little wider and they are too wide, same goes for the height.
Looking forward to hearing how the parts change works out.
If you don't mind me asking, where are you? I am in Texas.

Gruv2ths, I measured the 1000uF and have ordered SLPX102M200C4P3 CORNELL DUBILIER - diameter 25mm, height 45mm. Not really high quality but you are right, space is tight on the pcb.
By the way I'm in the city Leiden in the Netherlands. Also have 2x broken Play-5's lying here (1x PSU ticking and 1x amp stages blown up) . Ever done some work on those?

Gruv2ths, sorry one more question. Do you have the winding diagram for the transformer PQ3230 in the 36V section? I think mine is dead (would explain the broken Schottky diodes). On the primary side I only find one good winding whereas there are 3 pins with wires attached. On the secondary side no connectivity between the thick wires which run into the pcb. Will be tough to find a replacement...maybe need to take it apart and wind a new transformer myself. Thanks!

Hi Gruv2ths,

I tried both your riser card and mine with no change in the noise level issue. The noise exists whether the analog inputs are used or the source is digital streaming. I posted a video in YouTube. Hopefully you can access it at:

https://www.youtube.com/watch?v=l2rIuxriv_s

I'd like to get my hands on another logic board (i.e. the top board) to see if that would eliminate the noise.

Piperdog,

Have you ruled out a problem with the low pass filter (LPF) of the class D amplifier? The noise you hear may be "switching" noise leaking through the LPF...the electrolytic capacitors may need replacing.

Pietje Puk - Let me make some measurements on a 36V converter transformer that have here. The continuity should be the same on mine as yours, different turns ratio though I think? (given the lower mains voltage here). If it's the transformer, all is not lost. With the bias converter transformer, when they go open usually once removed you can see where the winding burnt off the termination pin. Fingers crossed that if your transformer has blown open that it can be repaired the same way.

Piperdog - Thanks for the youtube, that helps. Very weird! Wondering if you had a power surge, if maybe some of that over voltage made it through the bias power converter and up to your logic card. If you have a microscope, can you look for cracked ceramic capacitors? I suspect noise that should have been damped is getting in and causing that weirdness.
Pietje, he is using a known good power board so hopefully the Class D stuff is ok.

Gruv2ths thanks. I get the same so transformer should be fine then. Need to peel back the onion a bit more. Parts have arrived so will start replacing the diodes and capacitors. Also managed to fix one of the Play5 (1st) gen which I bought recently. Just had to replacw the 10 Ohm resistor in the power supply on the primary side.