JBL VRX932LAP Amp - Power flickering on and off in rapid succession

[JSmith]

PRX615M

Have you got the service manual?

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Oh and welcome to ASR.


JSmith

 

[d-class]

Yes, of course I already have the service manual, but I need this information from someone who has it in their workshop or has repaired it in the past.
If I want to try to turn it on with a lamp in series, should it stay on and work or not? So, is it necessary to connect it directly to the 230V mains?
It's just a precaution, since in my case, with the lamp, it doesn't turn on consistently; it turns on and off continuously.

 

[JSmith]

If I want to try to turn it on with a lamp in series, should it stay on and work or not?

A dim bulb tester can interfere with SMPS startup due to the voltage drop... SMPS may need a minimum input voltage to initialise.

Use a variac maybe instead of a lamp, so you can ramp up voltage gradually and monitor current draw. My guess is it won't start until it reaches the min voltage needed.

it turns on and off continuously

May be the amp protection circuit reacting to undervoltage or failed SMPS startup, not necessarily a fault.


JSmith

 

[d-class]

I used a VARIAC without the lamp and as soon as I exceeded 170V it turned on for 1 second and then completely burned out the entire power section, the 2 mos, the 4 drivers and the FAN7380

 

[JSmith]

I used a VARIAC without the lamp and as soon as I exceeded 170V it turned on for 1 second and then completely burned out the entire power section, the 2 mos, the 4 drivers and the FAN7380

Damn... that's most unfortunate, sorry to hear this.

Did you not have some form of current limiting upstream?


JSmith

 

[beavernuggetz]

When using dim bulb testers, keep a few incandescent bulbs around with different wattage capacities: 200/300 watt bulbs work great for power hungry amps and 60/100 is plenty enough for everything else.