AVT-150 mute circuit

[niak]

hey - i have followed the tips found on this forum about replacing the TD7293s and the AVT150. i have managed to source 2 whole modules locally and have replaced them in the amp. the amp turns on and the fuse holds but i get no sound out the speaker, if i plug headphones into the other outputs i get sound so i suspect there is a short in the mute circuit.

im a computer guy not an electronics guy, so i need some help in identifing what to look for.

can anyone point me in the right direction ?

[Enzo]

Somewhere on the maon board are transistor T104, zener ZD100, and cap C217. They are all in parallel. If one or more of them shorts, the amp is left in standby.

Normally some voltage must be on the standby pin of the power module. I have no idea, 5v, maybe 10v? No more than 15v. That is found on pin4 of the power module CONNECTOR. Not the powr IC. The 7293 power IC standby is pin 9. SO either see if there is some voltage there, or at the collector of the transistor or cathode of the zener. Or make sure that point is not shorted to ground.

[smash1]

Hi niak ¡

Here´s the part of a schematic that Enzo explains:

http://www.chaudio.co.uk/ServiceInfo...t150_61_02.pdf

At the bottom of the page at the right is t104,zd100 and c217.

I have the opposite problem.After replace the two power modules, and when the power button is on,it can hear a thunder sound during less than a second but the amp runs right.

Is the thump circuit fault ?? Any t104,zd100 or c127 are open ??

I can place in paralel on any of this components a jumper like a standby button to simulate this ciruit ??

Thanks in advance