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Working on another zpa0.3

Posted: Sat Mar 21, 2015 7:13 am
by vwdude
This one will be for sale when I'm done. I'm redoing the powder coat, repairing some blown resistors, converting to v2, recapping, and replacing all mini caps with audio grade caps. Also doing a general clean up and replacing the thermal paste. Plus I'm

Here's some initial shots...
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Re: Working on another zpa0.3

Posted: Sat Mar 21, 2015 7:49 am
by Alfaholic
Hi see you are keeping busy, i wonder if you got an remote terminal i need one because the threads are broken in mine.
I have fixed it but it looks like crap, i think the speaker terminals are the same please tell me if you got one :-)

Re: Working on another zpa0.3

Posted: Sat Mar 21, 2015 8:07 am
by trickyricky
Hey Alphaholic, give me the dimension for that terminal...I believe I may have one from a different amp (so it might not be gold plated).

Re: Working on another zpa0.3

Posted: Sat Mar 21, 2015 1:14 pm
by vwdude
I do have one. I have a parts amp that still has all of it's terminals (not the power but the rest are there).

Re: Working on another zpa0.3

Posted: Sat Mar 21, 2015 2:20 pm
by Alfaholic
vwdude wrote:I do have one. I have a parts amp that still has all of it's terminals (not the power but the rest are there).
I will send you a pm later, i got inspired by your tread and i just finished upgrading my 0.3 its only misissing that remote terminal and its perfect.
Im using white side covers from my 0.5 the new owner asked if he could get the black ones and i think it works with the white ones but one corner is cracked on both covers but i will glue them and hope it does not show.

Re: Working on another zpa0.3

Posted: Sat Mar 21, 2015 8:41 pm
by vwdude
Yea I mean that works but I personally wouldn't mix and match the ends. I can get that terminal to you no problem. Those power terminals are interesting. I guess that's your solution for the open ones. There's no good solution other than having a machine shop make new ones and then have it gold plated or something.

Let me know and I'll the party started.

Re: Working on another zpa0.3

Posted: Sun Mar 22, 2015 1:41 am
by Alfaholic
The power and ground are oem closed terminals, i also had to change the sensetivity pots they were bad and made alot of noize.
I will send you a pm i forgot yesterday i was so tired :-)

Re: Working on another zpa0.3

Posted: Sun Mar 29, 2015 1:21 am
by vwdude
Ok so some updates. I got both power supply boards completely done. That means changed to v2 and all caps were upgraded to nichicon audio grade caps. I also removed one side of heat sinks. Cleaned up the sink and found something had spilled under it, so cleaned all of that up. All resistors tested out fine. Enjoy the pics...

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And the heat sink...
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I also started the repair. There was 1 large 3 watt resistor blown, I changed 4 just to be safe and have the amp match on both sides. Also replaced a bad zener diode and he resistors on either side. I stil have 1 more resistor to change before the repair is done.

Re: Working on another zpa0.3

Posted: Sun Mar 29, 2015 3:19 am
by Alfaholic
Looks nice and clean i like the caps they look good, why did you change the caps on the power supply boards were the old ones broken?.
What did the audio grade caps cost a piece?

Re: Working on another zpa0.3

Posted: Sun Mar 29, 2015 6:24 am
by vwdude
All caps degrade over time. Beyond just leaking, as they get old it's a good idea to replace them. I figured as long as the board were off for the v2 upgrade it was worth upgrading the caps. Audio grade caps are about 5-10x the price of general purpose, depending on which ones you go with. For an example that I looked up, 10uf 35v, the general purpose one is $.05 and the audio grade one is $.71

Re: Working on another zpa0.3

Posted: Sun Mar 29, 2015 6:43 am
by trickyricky
Use "contactact/electrical" cleaner from WD-40 to clean those PCBs or something similar (just make sure it doesn't contain silicone). It will help make the board look new again without residue film left over.

Re: Working on another zpa0.3

Posted: Sun Mar 29, 2015 7:17 am
by vwdude
Ah ok I've been using 99.9% pure alcohol meant for cleaning electronics. It's doing an ok job but as you can see this board is pretty dirty.

I forgot to mention, while the power supply boards were off I replaced the PWM chip and installed a socket. I don't want to remove these boards again. I ordered enough to do that to all of my ZPAs (along with all of the other stuff)