problem with zpa0.5

marko · Post by **marko** » Sun Sep 23, 2007 5:42 am

got nath's amp here on my bench he asked me to look at for him, when powered up NO leds light up at all and the input fets are whizzing like crazy

i turned the amp off asap just incase, after removing the heatsinks nothing seams to be blown or cracked....

it has had new input caps fitted at some point and upgraded to 5600uf ones.

Mastiff · Post by **Mastiff** » Sun Sep 23, 2007 6:09 pm

sell it to me..

Post by **AVICJR** » Sun Sep 23, 2007 6:13 pm

Looks like the caps are leaking.

1moreamp · Post by **1moreamp** » Sun Sep 23, 2007 7:22 pm

No LEDs and "whizzing like crazy" Huh. Well Don't power it up anymore, it has issues.
By chance did you see its current draw when it was "whizzing" ???? This is important info to have, but don't risk damaging the amp again UNLESS you have a current limited power supply. Set it at 10 amps MAX. then you can Ge Whiz the amp again < Idle is around 2.5 to 3 amps typical>

No LEDs means no secondary voltage of any consequence, usually caused by a bad short across the power supply rails somewhere. I would start ohming out the outputs and then the drivers , and then the power supply diodes just for GP's... .

try some of this and PM me or direct e-mail me if you like

....C

marko · Post by **marko** » Sun Sep 23, 2007 9:30 pm

1moreamp wrote:No LEDs and "whizzing like crazy" Huh. Well Don't power it up anymore, it has issues.
By chance did you see its current draw when it was "whizzing" ???? This is important info to have, but don't risk damaging the amp again UNLESS you have a current limited power supply. Set it at 10 amps MAX. then you can Ge Whiz the amp again < Idle is around 2.5 to 3 amps typical>

No LEDs means no secondary voltage of any consequence, usually caused by a bad short across the power supply rails somewhere. I would start ohming out the outputs and then the drivers , and then the power supply diodes just for GP's... .

try some of this and PM me or direct e-mail me if you like ....C

only problem is the amount of devices in this thing, i could be here for ever

do i have to remove the devices to check ohms?

been a couple of weeks since i initially stripped the amp down and i'm sure it was drawing a ton of current on tick over but not sure now

1moreamp · Post by **1moreamp** » Sun Sep 23, 2007 10:41 pm

" throw it away " ??? Let me know when your throwing away collectible PG amps and I will stand in line to catch them as you toss them

Marko, just pull it down till you can flip the main board and do a ohm check across all of the outputs, they will show themselves as shorted if they are.

Most of the time folks blow the outputs and then there are current limit resistors that are open also.

The amp is all discrete so there are a lot of components, but this is what makes it what it is. If you don't feel like taking on this monster, I understand just PM me and I will give you a address to mail it to < Mine> so it won't go into the trash bin. I know this fella back east that wants one.

marko · Post by **marko** » Mon Sep 24, 2007 7:46 am

lol, i won't be throwing it away and i've not been beaten on a pg amp yet

besides it's not mine to throw away but a very good friend of mine (nath off here).

so i'm looking for a reading on the ohm setting accross the outside legs? and check for open resisitors

Post by **stipud** » Mon Sep 24, 2007 7:10 pm

I branched off the derailment to a new topic... Sorry about that Marko

marko · Post by **marko** » Mon Sep 24, 2007 9:40 pm

stipud wrote:I branched off the derailment to a new topic... Sorry about that Marko

thanks, wonder wtf happened

the derailment was interesting but by no means helped me!

theburb · Post by **theburb** » Mon Sep 24, 2007 10:25 pm

marko wrote: thanks, wonder wtf happened the derailment was interesting but by no means helped me!

just find a new one....with all the time and money u will spend trying to fix it before u give up and ship it to the states and whatever else is not worh it....especially since something else will more than likey bomb out on that amp when it does get fixed....you can find a nice working one for the cost it will finally take to fix that one....i hope that helps you now

Post by **stipud** » Tue Sep 25, 2007 7:11 am

theburb wrote:
marko wrote: thanks, wonder wtf happened the derailment was interesting but by no means helped me!
just find a new one....with all the time and money u will spend trying to fix it before u give up and ship it to the states and whatever else is not worh it....especially since something else will more than likey bomb out on that amp when it does get fixed....you can find a nice working one for the cost it will finally take to fix that one....i hope that helps you now

Drop it. Keep your opinions on the ZPAs to your derailment thread.

Marko is trying to fix it himself... he has repaired many PG amps in the past.

1moreamp · Post by **1moreamp** » Tue Sep 25, 2007 2:48 pm

Afternoon Marko,
I been way too busy sorry my friend just PM me and I will get you square my friend.....Cheers C

theburb · Post by **theburb** » Tue Sep 25, 2007 3:04 pm

stipud wrote: Drop it. Keep your opinions on the ZPAs to your derailment thread.

Marko is trying to fix it himself... he has repaired many PG amps in the past.

im sure he can fix the amp but there comes a point when you could just replace it for less.

its not right for you to just step in and tell me to be quiet without even hearing me out....thats bs....i was being serious dont get bent out of shape just because i was stating what i thought was a good solution....these bigger amps almost always take about 100-150 in parts to get them running right no matter what pg amp it is....it takes longer to find these parts then it does to fix the actual amp....for that price he could sell that one he has on ebay as is for about 150-200+...with that money then he could just buy the almost mint amp Wakeup is trying to get rid of and call it a day..

Post by **stipud** » Tue Sep 25, 2007 3:27 pm

I've "heard you out"... you already stated your opinion on the ZPA amps, and I even made you your very own thread for that. I don't need you to come back and start the same derailment here again.

He's asking how to fix his amp, not how to get rid of it. If you went to a classic car forum and asked "how to rebuild my motor", and some guy came along saying "just burn it to the ground it's trash buy a new one". That adds absolutely nothing to the discussion... what kind of reaction do you expect?

$100-150 in parts is a gross exaggeration if the problem is simply a number of FETs. On this forum some of us like to restore and rebuild our amplifiers, not just throw them out because we can't be bothered to diagnose what the problem is.

I've fixed similarly glitching amplifiers for a whopping $0 before. A cold solder joint just needs a quick lick of a soldering iron, or a quick spray of contact cleaner in the right spot is all it takes sometimes. Boy would I have been disappointed if I threw out a perfectly good amplifier that I could have fixed for free!