Mackie/Tapco Thump fault

[jbmdisco]

Hi Guys,
i was donated a pair of thumps recently. 1 working perfect. The other had the dreaded pulsing power light. After a few checks on the PSU, which checked out fine, I replaced the amp module with an OE part. The pulsing led has been cured but I cannot get any output from the amp! Both the driver and top end have checked out as good. I have put a signal directly into the amp and even used a speaker cab I use for repairs but still nothing. Any ideas ?? I have it on the bench just now having a good poke about but am now out of ideas!

[The Dude]

A schematic would help. There are also different models of Thump's. We don't even know which one you have.

[J M Fahey]

^^^^^^ that.

Besides, just thinking off the top of my head, that amp might:

* have a damaged supply that canīt put pout any real current, you measure it fine inder no or very light load, as soon as amp starts demanding (even idle current) it shuts off rails (even if other supply parts still function).

* the amp may be connected wrong, either to supply, input (so nothing drives it) or speaker (so nothing reaches speakers), and maybe others.

*the amp may be sensing "something is wrong" and self muting

* you might have no apply the "unmute" signal.

So start by checking (on amp board itself, on pads and tracks) that supply voltage reaches it (a dead connector might be stopping that), with power OFF that grounds are really connected to chassis ground, etc.