Jbl Amp Not Working

[bowdown]

Hi there i was wandering if someone can help me with a problem i have with a JBL DA1002 car amp.

The amp does not turn on, but the "on" light glows really dull on and then off then on again, just keeps doing that. I have checked for broken tracks and also checked all output and powersupply fets. I also replaced a tl494c ic and still the same. Please help with any suggestions.

Regards

Bowdown

 

[anatech]

Hi Bowdown,
Well that tells me the amp is trying to start but protection is shutting it down. Try to power the amp stages up partially with an external bipolar supply and troubleshoot from there. You may find high current draw or DC offset.

-Chris

 

[mastertech]

basicly the power supply has sense lines on the amplifier side, any variations
in these could have caused the shutdown,then go back and troubleshoot the
power supply,simply changing the ps control chip doesnt mean the power supply
has been looked at properly, smps are harder to fix than linear ones due to
their complexity

 

[anatech]

Ahhh, but zat is why I suggested powering the amp section by itself. If you know that's working you don't have to chase through protection.

-Chris

 

[mastertech]

have no problem with that