lilviper wrote:Check the paths, i read something on how their system works on here. Somewhere.

Sent from my SM-G960U using Tapatalk

yes, I read in the old post that there was a problem with the thermistors but these are ok...

Did change the SG3525 but still the same problem. Only difference now is the green LED is flashing...
If the SG3525 gets powered up it should send 6 volts to output A and output B not? I have no power on output A and B...

looks good!

let's start from the beginning. when I power up and measure the rail caps I have 0 volts (13.6v on the PSU caps). So I decided to take out the 8 PS FET's. They are type P55N06 with 33 ohm gate resistors. I tested the switch function of the FET's once they where out and they al seem to work (tested w...

Hi Jason thank you for the info. I work on 2 project's now. the 2SC2389 part if for another repair (ZPA0.5). The problem is that the guy who repaired this did not change the counter part, some diodes are blown on the power supply board. D'ont know the damage yet... did some more testing on the zx500...

Hello Jason!
You are the man. I did a quick test on the output's but non of them have a short. The amp puls almost no current just the red led is on. This weekend I continue with the repair.
something else : do you know a good replacement for the 2SC2389 BJT?

Hi everyone

my ZX500 is in overload mode (red led is on) ventilator is working.
the 2 thermistors are ok, no short in the BJT's and FET's.
It drives me crazy. Any ideas to help me further?

Welcome
you can use one M25 bridged for the left channel and the other for the right channel. Than you have perfect stereo separation and twice the power.
With this setup you will hear more difference in sound quality than the bi-amp setup (one for tweeter and one for mid range)

you find the problem, good for you!
is this transistor part of the clipping circuit?

thanks for the replies.
Does anyone know how many electrolyte caps there are in the signal path for the ZPA amps?

I want to keep my PG collection in good condition. To do this I want to change not only the big PSU caps but also the little ones. Most amps I have are the M / MS / ZPA series (ZPA is my biggest collection). Some caps have shrunken folies. Can anyone give me advise what are the best options to repla...

you can measure voltage across the output emitter resistors. Make sure you have a microvolt meter.

That's a very clean M100 you have there! If the 6 blue psu caps are still the original ones then replace them first before you do something else! They catch fire if you don't. The yellow pots are for bias. Take a picture of them or mark the position with something. Than turn them slowly counter cloc...

Hello Anders

idle current should be no more than 2A.
did the amp had repairs before?

thank you for the info!

it sold for 2.000USD

this is on ebay right now.
I see no inputs and outputs for the MS250 section?

Wow, that is a nice collection. Didn't you had more ZPA's?

The M100 amp in 4 ohm configuration deliver the goods like few others even today. They are worth the trouble...

Hello Jason

didn't know that the third digit is the number of significant digits. So learned something new today. Thank you!

I opened up mine:
C7 : 103 M5C = 0.01µF I think it will be 50V but I can't confirm that, you need the schematic for that.
C15 I can't find. Can you tel where exactly it is on the board?

this fuse block has 1 input and 2 outputs. I think that the AGU fuse has a maximum of 60 amps. If you put 2 AGU fuses of 60A in parallel you have 120 amps of protection. This is the reason why PG made this design like it is I think. You have more possibilities to protect your amp with the correct fu...

Hello Fresh like other forum members said priority number one is changing the 12 blue PSU caps. You can find a lot of info in the "how to" section. On the crossover card there is a push button. Push it and tell us what happens (when the amp is working and connected to the speakers) There i...

Hi Ttocs

did the test with the one I have: with fuse = green LED, without fuse = red LED. Switch in off position: no lights.
do you have a multimeter with a "beep" test? If so, use it to test the fuse. It's possible that the fuse is not 100% open.

Hi Jason when I changed the SG3525 the problem in the front chanel was solved but not in the rear channel. it was like you said, a blown 33-ohm resistor that is connected with the part DI 763A. Can you tell me what the function of this part is? I like to learn and know what I'm doing. Now the M44 so...