Phoenix Gold Phorum

Hello all,

I found a couple of MQ430s that Im likely going to purchase. Both amps look fairly decent and the outputs all tested out fine except for one channel in one of the amps and neither has had the caps replaced.

I haven't been able to find any manuals or how to's on these amps and what I might have to do to get the channel working if it does have an issue.

Any help would be greatly appreciated.

If one channels doesn't work you have the other three you can use as reference, each channel is pretty much exactly the same...a copy and paste design.

Thank You. I wasn't aware of that.

I also know how to solder fairly well so Im ok on that aspect.

Any info on how to test the components or the processes involved for the different types of issues? Bench test and trace the issues?

Gotchas that sort of thing? I read somewhere that if I replaced components on one channel I should replace them on all channels; is that correct?

If you are unsure of what you are doing, I would start here: Basic Car Audio Electronics. There is lots of material there about everything car audio related, including some basic troubleshooting and how to test components. The owner of that site also sells a very in depth and highly recommended tutorial on the details of car audio repair.

For "gotchas" the only really big ones for PG amps are, replace the caps. Even if you don't think they are leaking, they are. Replace them before putting power to the amps, they can and will burn holes right through the boards. The only other "gotcha" is knowing how to solder "fairly well" is probably not good enough. The PG boards are pretty fragile, I think mostly because they are not slathered in solder resist like 9 out of 10 other boards are. Too much heat and you will lift pads, not desoldering big power components like outputs or filter caps 100% perfectly means you will almost certainly pull the through hole plating out of holes. A good temperature controlled iron and proper desoldering equipment is necessary to do the job correctly. Once you pull the plating out of a through hole or pull a pad off then you will have a much bigger and more complex repair ahead of you.

As for your question about replacing components, the answer is no. You don't have to do anything with the unaffected channel. What you are probably thinking of is A) when there are parallel devices and only one fails, they all need replaced, B) when one transistor fails and it has a compliment, the complimentary device should also be replace, and C) when a transistor that is part of a differential pair fails, it's paired transistor must be replaced and identical to the other in the pair.

Good luck,
Jason

Thank you, much appreciated.

the man knows his stuff

Steve, jacampb2( Jason), is who walked me thru on fixing my zx450; he is INCREDIBLY KNOWLEDGEABLE, & I learned most of what I know on " repairing" , from him-