Repair ZP120

piper

Lyricist III

To clarify my previous post. The presence of noise is more consistent than I thought. When either the amp is muted and/or the music is paused, the noise disappears after several minutes and the amp is absolutely silent. Otherwise the noise exists. I have the amp hard wired by Ethernet cable to my Bridge which in turn is hard wired to my router.

Trending Lyricist I

Hmmm.. This is a new one for me.
Does the AMP work at high volumes, even though the clicking exists?
Can you take a video with your phone and upload to YouTube so I can hear it?
So a couple of things:
Have you tried removing and re-seating the riser card?
Have you tried using your riser card as opposed to the one that i shipped with the power board?
Does your phone app indicate that there is a firmware update available for any of your system?

piper

Lyricist III

The noise sounds to be a constant level. it's a crackling sound. The volume of the amp works fine - low to high volume. At modest to high volumes the noise is masked of course. My system is update to date re s/w. I'll try reseating the riser card as well as using mine. I can also send you a video with a recording. However, I'm going out of town until after New Year's so I likely won't be able to post anything further until mid next week. Thanks for the suggestions. I'll pursue next week.

Trending Lyricist I

Also, are you using the aux/analog input or a streaming source?
If this is a analog source, it could be your source or the RCA cables. Likely grounding between the two.
When you push play from your controller, you are enabling the 36V supply which powers up the amplifier section.
That supply dies after a while once you push stop. Sounds like the noise is following the 36V supply on and off.

Let me know what you find once you're back. Happy New Year!

T

timc995

Prominent Collaborator I

Re my ZP100...

The problem it had was that it was not getting any output on the left channel, and within the app it was detecting a fault. This fault caused it to reset the volume to low levels. This made it unusable as an AMP and also not particularly useful to use the RCA outputs. (I'm not sure -- maybe I could have set those to fixed output -- not sure).

In any event, I opened it up today and couldn't see anything wrong with it. However, during my poking around inside, I must have bridged something... I think It was from the AC to DC board to the chassis as I tried to measure the DC voltages there. There were fireworks and popping. I quickly unplugged it.

The interesting thing (to me) is that it is actually more usable now than before! I took the whole thing apart looking for blown capacitors or anything similar. The only thing I found was the both STA505 chips were quite obviously blown... they both literally had pins missing/blown off (see the image). I figured it was very dead and reassembled it to prove it. Lo and behold... It booted up the first time. Not only that, but it stopped throwing faults! There was no audio on either speaker (not surprising given the amp chips were dead). BUT... both RCA outputs were working. SO despite my boneheaded mistake, I now have a device that can at least be used as a sonos connect (no AMP).

I'll probably try to replace the AMP chips. I have two STA508s. These are the chips that are used in the ZP120, but they are pin for pin compatible with the STA505s that are used in the ZP100. I imagine that even if I am successful in replacing the AMP chips (no small task), there is a high probability that there are now other problems on that board, given the fireworks. On the other hand, the blown pins on the amps look to be only the positive and negative supply pins (4,5,6,7,12,13,14,15). If the board traces survived, maybe all the damage is isolated to the amp chips.

Pietje Puk

Trending Lyricist I

Hi folks, I've got a ZP120 with blown power supply too. When powered up I smell "semiconductors". I've been testing an found both Schottky diodes (D16002 and D16006 text: VC3 type: VS-30BQ015PbF) are broken (virtually shortened 0.06V anode-kathode on the diode tester and 0.46V in reverse direction). It seems these are between VPRI and the drain of the Mosfets on the back. Of course I can replace both but just wonder if this is a sign of the main problem. A bit suspect both have blown. The mosfets seem to be okay and also the other pair of diodes in the same circuit (U3J - MURS360T3G; ultrafast rectifiers). Any suggestions?

Trending Lyricist I

I don't have a unit open in front of me. Can you take a pic of your unit and circle the parts in question.
I know them better visually then by ref-des.

They sound like the 36V supply rectifiers. Could be them or you have a short on the 36V rail. I have seen both problems.
Remove the diodes and see if the parts are shorted.

Pietje Puk

Trending Lyricist I

Gruv2ths, thanks for the quick reply. See picture attached. I have lifted one side for both diodes and 36V rail has no shorts.

Pietje Puk

Trending Lyricist I

Checked a bit more....smell wasn't semiconductor but electrolyte. The 33uF 400V capacitor died (C16102). See photo....I think I will just replace all of them. Clearly some ageing of parts.