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ZX475ti more than an LED problem

Posted: Tue Aug 19, 2008 12:04 am
by GTS_t
The three blue leds on my zx475 go out when I refit the amp cover then relight when I remove it.

When the lights are out there is 28volts across the screws that hold the led board which drops to 14volts if the leds decide to work.

Are these voltage correct?

What could be wrong with the led board?

Thanks.

Posted: Tue Aug 19, 2008 8:37 am
by rolandk
The voltages you stated are correct, the problem is most likely defective LED's.

Posted: Tue Aug 19, 2008 6:57 pm
by GTS_t
Title edited to reflect a broadening problem.

I think I fixed the leds by resoldering a joint but in the final check before I refit the case I found one of my front channels was out.

I hooked up my test speaker one channel at a time and all I got out of one channel was pop...pop...pop at intervals of a second or so.

I had this problem with the amp a couple of years ago and it fixed itself just as it did today except last time it was the other front channel.

Oddly, I recall last time this happened the leds had been out for weeks but when I popped my trunk to see why the channel died the leds were shining brightly again.

I emailed PG tech support and they said the leds and rca inputs were on one board and it was probably the board connectors.
I took the case off but couldn't see a problem so I put it back together and all worked well until recently.

Have there ever been any shorting issues with the led sub board being back to back so close to the board it mounts on?

Posted: Wed Aug 20, 2008 7:42 am
by rolandk
The power LED's shouldn't affect individual channel operation. Could be a intermittent contact on a switch or pot- try working them up and down several times. Do the 8 red LED's on the main PCB light up? If not the problem is on the main board.

Posted: Thu Aug 21, 2008 4:50 am
by GTS_t
It only played up briefly so i didn't get a chance to look at the red leds.
Front gain pot felt a bit edgy first time up and down.
It feels smooth now though.
I hope the fix is this simple.