Carver M-500 power supply repair

[hifiworkshop]

Hello guys,

does anyone have good experience with the power supply part of the CARVER M-500?
The amplifier is working well at all but sometimes when turning the amplifier OFF the circuit breaker of the outlet pops. (this happens not always, seems to be depending on the phase angle)

Could be ZD503 and ZD504 the reason as they are not original anymore? (Its impossible to find Z-Diodes with 26,5V - was probably special made for carver?)

BR,
Dave

 

[Skywatcher]

Hello guys,

does anyone have good experience with the power supply part of the CARVER M-500?
The amplifier is working well at all but sometimes when turning the amplifier OFF the circuit breaker of the outlet pops. (this happens not always, seems to be depending on the phase angle)

Could be ZD503 and ZD504 the reason as they are not original anymore? (Its impossible to find Z-Diodes with 26,5V - was probably special made for carver?)

BR,
Dave

What outlet? Wall outlet with a GFI breaker? If so it is sensing leakage to ground. Use a non-GFI outlet.

 

[hifiworkshop]

What outlet? Wall outlet with a GFI breaker? If so it is sensing leakage to ground. Use a non-GFI outlet.

Hello, its a europe installation so theres no direct circuit breaker in the outlet.
Its the 16A circuit breaker in the main fuse box popping when turning off the amp (but not always and not the RCD)

 

[Skywatcher]

Hello, its a europe installation so theres no direct circuit breaker in the outlet.
Its the 16A circuit breaker in the main fuse box popping when turning off the amp (but not always and not the RCD)

Ok, I see.. Hmmm, I really don't know. Check the 100 Ohm resistor coming off the SCR make sure it hasn't drifted high. Have you checked datasheets for the Zener diodes? They do have a tolerance range and I don't think they have to be exactly 26.5v. I gather you aren't the original owner so it is possible someone else changed the Zener diodes attempting to solve this very issue.