Pioneer gm-x324

[ADRIANd]

Hi this amp fáiled yesterday i have many years with it.
It gived a nice sound. But it do not power on. Anymore 🙁
Checking it i found suspicious voltages that don't match. the voltage the service manual said must be.
The PS is not oscilating,because ta8194z do not actuvate upc494c, the TA8194z had this voltages:

1. 0v
2. 0v
3. 10.28v
4. 12.16 v
5. 0.54 v
6. 0
7. 0.25v
8. 0v
9. 0v
10. 12.1
11. 0
12. 12.16 v
13. 12.1
14. 11.64
15. 0
16. 0



The pin 4 must be near to 0v. If is 12 volts it Will not polarize the transistor and the transistor will not send 12 volts to pin 12 of the upc 494 c

I post the part of the service manual with the correct voltages the IC must have

Thanks in avance for the help

 

[Perry Babin]

Check D604

 

[ADRIANd]

Thank you Perry i replaced the zener, amp is alive again, all voltages as the manual .

Is only 30 watt rms pero channel but i like how it sounds!!