Help for my Peavey PV8.5C

Hello Everybody!

I bought in stock 3 Peavey PV8.5C.....:confused:
All the amp had the same problem.... 1 channel broken, the same channel :xeye:
I repaired the driver board with exactly the same components (this it could be ok) and the power board with the equivalents transistor MJ15024 and MJ15025.
All the power resistors on power board are ok now but with the new one power board I have a problem with DDT protection..... with a very low input signal the light DDT turn on and I can't to understand what happens.....

Can you help me? :bawling:

Thaks for all replay.
 

Netlist

diyAudio Moderator Emeritus
2003-01-18 9:50 am
In the CS series, on the driver board near the input, a small capacitance (.1µF) is often the problem.
It is connected between ground and the gate of the FET.
There's only one FET per board (hint) and the PV8.5C has the same circuit. From the (very bad) schematic I have, it would be a electrolyte of 2.2µF.

/Hugo
 
Hi guys

yesterday I tested the capacitor near the fet but it's all ok.....

I tried to change the new power board with the old one, that original and with the original one it's all ok..... the DDT led don't turn on.
I tested the output signal and I saw this.....
with very high impedance (just with oscilloscope) it's all ok but when I placed the low impedance (4R7 power resistor) I have a problem with the clip of DDT circuit.

I have this problem just with the power board with MJ15024 / MJ15025
with the old board it's all ok....

What do you think about? :confused: :)
 
Hi guys!!!!!!! :D :D :D :D

I found what's happen on my power amp!!!!
I bought the power transistor on Ebay shop by chinese seller...... and all the transistors was fake :smash: :smash: :smash:
I bought others transistor MJ 15024 / MJ 15025 and now my PEAVEY has a great sound!!!

In this case in Italy we say: CHE SOLA!!!!!

So guys look where you buy transistors and all the others electronic parts for your circuits!! :whazzat: :whazzat:

Thanks for all !!!