Is this acceptable?

[trickyricky]

just an update...my DMM shows no continuity in either side of those lines. could that be what caused me to blow the fuse? I dont even know what that block does. never seen it before on any of the boards that ive worked on.

What block? The Wima cap?

[vwdude]

yes. thanks for the info of what it is, never seen them before. so if it were removed from the system i would think it would leave an open circuit, not a short. so maybe this is not the issue?

[vwdude]

the solder on the little blue piece doesn't look like it got hot enough to bond properly. I would start simple and just touch those spots with an iron and get the solder melted/bonded properly and see what happens.

what little blue piece? I might be color blind but i dont see anything blue in any of my pics. if something needs more soldering that would make sense to me, i just dont see it.

oh, and BTW, for those who are reading this thread from the start, I dont think I want to sell this once its fixed. I might use it in my car along with the McIntosh, or it might end up in my wifes car (first ZPA in a prius???) or my father in law might use it in his mustang. he really fell in love with how my car sounds and I told him that the ZPA should sound as good or better than my Mac.

[ttocs]

Sorry I thought the red cap was blue for some reason..... Was up too late I think.

[zeropoint0.5]

the red wima cap on the back side is Original....most of my zpa's have it also.......

for the ps section, did you already replace all 16 fet's and all 16 gate resistors ??

i would certainly resolder that one other transistor( not the one in the ps section i mean )

[vwdude]

yes they all have been replaced. i got rid of that nasty solder job, i just couldnt clean up all of that garbage around it.

So i repaired the trace leads going to the wima cap. I think I need to let the stuff dry before its conductive as i keep testing it and its still not conductive even though theres a decent amount of material on there.

[ttocs]

I can't figure out what you did there but it looks like you made it worse to me. Is that solder and if so, is it now going between the contacts?

[trickyricky]

Its a 5% 100-250v 0.01uf cap, wima has different series (some are prefer over others for this specific purpose).

[vwdude]

I can't figure out what you did there but it looks like you made it worse to me. Is that solder and if so, is it now going between the contacts?

No that's not solder it's trace lead repair. Think metallic paint pen. I first used the protector pen to cover the exposed area then I redrew the lead connecting the two points. I verified conductivity and its good. I redid it, let me get a new picture when I can.

Its a 5% 100-250v 0.01uf cap, wima has different series (some are prefer over others for this specific purpose).

Thanks. That is helpful. What is its purpose in this circuit?

[trickyricky]

Enhance SQ, decoupling.

http://www.diyaudio.com/forums/digital- ... itors.htmlHere's a link where you can read more about them (but feel free to google, lol).

[vwdude]

i googled, but what i cant figure out is how that being an open circuit caused my amp to act like a dead short. I am trying ot figure out if its worth testing the amp again, or if i need to spend more time to figure something else out. I took all heat sinks off and everything looks kosher. I dont see any bad solders, loose copper, or anything else that appears to be shorting or out of place.

[trickyricky]

Where are your dmm test leads when you get this "short"? That wima cap will not short or cause anything to short (unless it was installed in the wrong part of the circuit....is there an electrolytic "wet" cap on the opposite side where that wima cap is, in other words it it parallel to a wet cap?

[vwdude]

I didnt add this to the system. as far as I know, it was installed by PG. there is a resistor run in parallel with the cap.

[trickyricky]

Its bypassing the wet cap, am sure that resistor goes to a small wet cap. Its either factory or a SQ mod, either way that would not cause any thing to appear shorted.

NOW LOOKING at the picture you can see the traces are BAD. They are intermitting with each other....use some solder wick and pick up some of the solder to prevent any shorts. SORRY I should of caught that.... UNLESS is what you stated in an early post and its just some sharpie marker...I would still check continuity between all those points to make sure there is no shorts.

[vwdude]

You had a good point. I cleaned off the "paint pen" and used a coating to protect the leads from underneath (ground, right?) and redid the trace leads with that metallic paint pen. Continuity looked good. Heres a picture, along with some other pictures as I reassembled the amp again.


new caps:




Soldering points:



with the new plexi and the "not exactly OEM" sticker:

[zeropoint0.5]

where did you get that sticker from ?? it looks pretty nice..... is it on the upper or under side of the

plexi ??

how far are you now with this amp ?? still have problems ??

[vwdude]

Thanks for inquiring.

There was a person on ebay that sells other PG logo decals. I sent him this design and he did his best to replicate it. He sent me 2 or 3 of them, so let me know if you need any. Its on top.

So I have been very busy but I did try one test. I used test leads (18 gauge wire) hooked up to a small lead acid battery. It blew a 5a fuse. I tried to replace the 5a fuse with a 30a fuse. The wire got really hot, the fuse didnt blow. Whenever i touched the remote wire to the power, the fans would try to move, but didnt seem to get enough power. I have some 4 gauge wire but I need to get a fuse holder and a few size fuses to try it with more juice. I would think that if something was shorting it would have shorted with my test. I guess the ZPA just uses a lot of current even when no signal is going to it.

I also got busy with another blown amplifier that I bought around the same time as the zpa0.5. Its a PPI PC2350, and it turns out it was in "the beast", owned by Alma Gates to win the world SPL record. Once that one is done too I will test them both. They would work well together in a pretty crazy setup.

Heres a few pics of the PPI amp, and how I know its from their Bronco...



Now, for the proof that it is what I say/think it is:
S/N 3. Also, someone wrote 26 in there, I assume its #26 of the 32 amps.


If you google this amp, you will find photos of how this board should look from the underside. Those copper bus bars are not present. They appear to upgrading the grounding of the FETs, possibly allowing 1 ohm operation. Also, the yellow jumper, making it a mono amp full time. Factory modifications to "cheat" for their factory sponsored vehicle:

[RayBuck]

Crazy...Back in 96 we stored the bronco at the stereo shop I worked at. One of the guys that worked for PPI had a yellow ford ranger with a modefied PC 650 with front rear and sub inputs and it also made more power.

[ttocs]

yea back then if you wanted something special done all you needed too do was have you shop ask the rep and write a check. Wish we could still get service like that as back then I wasn't in the financial position to do anything custom and now that I am its not an option.

[vwdude]

So I tested the ZPA again. It didnt blow any fuses, but all I hear is a clicking noise. Its not powering on the fans and the LEDs arent lighting. I am going to take it all apart and check the caps to make sure none are shorted.

Also, when I put in the FETs, i pushed them down flat. I am wondering if it damaged them as I think the leads might have pulled out a little. I tested the resistance on them afterwards (realizing that might have been a bad idea) and they still seemed ok. I will order all new FETs, and I will get twice as many as I read somewhere that its better to match them up (they all have different resistances, so match the closest ones). Any validity to this theory? The rest of the amp looks ok.

[vwdude]

No ideas? or is everyone just real busy?

i tested the caps and they look good. none are shorted and all are grounded properly. all positive sides are also properly connected. next step is to order all new MOSFETs.

[vwdude]

So another question... I went to order a new set of irfz48, but I realized that there are different versions. the voltage and current ratings vary on them. Anyone know if it need 55V or 60V? 50A, 61A, 64A?

[vwdude]

dang, i either used up all of my free advise or this thread is getting ignored because its too long...

I think i found my issue...when replacing the FETs I found one lead going from the FET to the resistor was damaged, lifted from the board, and MIGHT have been touching the bus bar that it snakes under. I am repairing that today, along with all new FETs again. The resistors still look and test great, CAPs are good still, so all new FETs and I am paying attention to each lead to make it makes proper contact. With all of that done I will retest it, and fingers crossed, it should work.

[ReneBMW]

And, is it working again?

[vwdude]

Not yet. I decided to focus on my install and once that's done (almost there) I will finish the repair.

At this point I removed the rectifiers to separate the power supply from the rest of the amp. When I power up, if I still have a short in the power supply fets then it's still a power supply issue, if not then it's somewhere else on the amp.

I built my install around the empty case for the ZPA planning to use it but I have a PPI amp standing in until this amp is done.