Repair ZP120

Will do gruv and thanks for the warning. I have worked with electricity at different voltages from 125V house to low 5V circuits but never really worked with power supplies. I suppose I am going to have to open this thing and start a visual inspection to see if there is anything indicating what the problem could be. DO you have any theories?

Thanks gruv. That what I thought too. When I plug it in, no lights, no burning component smells. I do see the table lamp beside the plug flicker momentarily like the amp is drawing power. That seems normal.

OK I have an update. I successfully built and tested the dim bulb tester today and decided to plug the connect:amp into the tester to see what happens. I was expecting the bulb on the tester to glow bright indicating a short, however the bulb went momentarily bright and then quickly dimmed out. I am using a 60 watt bulb in the tester btw. I don't have time to open the unit right now, but I was hoping the m0untainman or someone else on this thread might be able to tell me what my results indicate.

Thanks in advance,
Andy

Thanks! I just got notice the unit shipped and will be here next week. This weekend I am going to build a dim bulb tester and am planning on following Daniel's blog on disassembling the AMP. I am pretty good with soldering and have already checked out some possible part replacements on eBay.

Edit: I just found a site with some pretty good directions on building the dim bulb tester: http://www.geek-tips.com/2015/11/22/dim-bulb-tester/

Ando, did you get the ZP120 on eBay this weekend that went for $50 ish? If so smokin' deal!

No but I saw that one after it ended. That was a good deal! I got a newer CONNECT AMP for $150. Hope it will be an easy fix!

@m0untainman and @gruv2ths: Thank you both. I will be opening the unit when it arrives and will update this thread once I do.

Andy

Tough question. There is no go-to source. Some of the choices that Sonos has made are exotic, like the integrated PWM they use for the bias converter. They use a non-integrated pwm for the amp power supply, also not available from Mouser and the like. You can always get stuff from China via eBay for example.

Awesome stuff! I was able to remove mine w/o removing the caps but it certainly would have been easier w/o them. One tip... the heat sink paste Sonos uses is really cheap stuff. If I didn’t know any better I would think it’s just white lithium grease. If you remove the PWM, clean it and use the arctic silver 5 thermal paste. It will distribute the heat much better.

Thanks. I would like to share a couple of items that may help others...

I have no idea what kind of solder that Sonos uses, but it is insane. In order to get it to melt, I had to get my Hakko iron up to 900 degrees. 700 (its default) would barely get it to melt. Getting it off components was a chore. That PWM and heat sink took a good 45 minutes to get off along with about 2 feet of desoldering braid. I am surprised I didn't destroy contacts as I really had to put that iron on for a while to get that solder to move. I tried a desoldering pen too, but to no avail. The best way to get it off was keep cracking at it with desoldering braid. I would love to hear if anyone has any hacks or ways to deal with such a problem.

Also, the dim bulb was brilliant. What a great tool to build. It is critical for testing any sort of power supply to keep you from blowing more components. Without this, I would have destroyed multiple resistors and thermistors that kept blowing. I built this for about $25 and you can get the parts at HomeDepot:

https://www.youtube.com/watch?v=rDe6oLKm-ao

This one was nice and clean to make - took about 10 minutes. This helped me trace the hot part. A 60 watt bulb seemed to do the trick for finding the failed component. I tried a 200 watt bulb and it let too much power through, so the bad components would get raging hot quickly. From my readings, the hot part is almost always the culprit for a failed component.

The best resource that I found for fixing and diagnosing power supplied is here:

http://www.electronicrepairguide.com/Smps-repair.html

The guy sells a PDF book that details everything from how to test different components to what tool to use. He has a nice chapter on a dim bulb tester. That site and doc really walks through the different sides of a power supply and what to look for. IMHO, that was invaluable.

Anyways, I really hope this helps others. This was a great learning experience and has given me the confidence to perhaps start hunting for bad Sonos products on eBay and fix em up. ;-)

Final words... I really want to encourage people to post in these forums for help. We CAN fix these things and with a great community like we have here, we can keep these things running. 🙂

New PWMs and SCK 054 Thermistors finally came in from China. I replaced them and just as I thought, the PWM pulls down the voltage. Checked at 13.03V on pins 1 and 3 on the PWM 😉 Fired up the dim bulb and it went dark. Shut off the power and put the wifi cards back in. Moment of truth... fired it up again with the dim bulb... and the white LED flashed.

Waited a few minutes and opened the iPhone Sonos app. Bob is your Uncle! There it was in all its glory and works!

The Sonos lives and is revived. Total cost for replacement parts: $3.00. Total opportunity cost (I almost tossed it)... $500. Savings to fix it myself: $497.00. Priceless.

I want to personally thank @gruv2ths for the insight on this, and @chicks for the dim bulb ideas. That sent me on a Youtube and reading spree that gave me the tools and confidence to diagnose and fix the problems. Thanks for all the help!

Yes that is with the PWM installed.

I am reading 13V across pins 3 and 1. That is with the dim bulb installed so it is probably a little bit higher.