GK 150MBS Help

neddyrow · #1 10-04-2012, 08:23 PM

Recently my gk has started thing where 15 seconds after I turn it on, it does what I call the "static monster" and is very staticky and fuzzy when I'm trying to play through it. The weird thing is that if I turn it off and on again 1 or 2 times, it goes away and is fine until I turn it off. Can anyone shed light on this situation I'm in? Thanks

fdeck · #2 10-04-2012, 09:56 PM

The first thing to do with virtually any amp is to exercise the effects send and return jacks. Just plug and unplug into those jacks a bunch of times, or try playing with a patch cord in the effects loop. Same for other jacks like auxiliary inputs.

Try isolating it to the preamp or power amp by breaking into the signal chain at the effects loop.

Otherwise, a "thermal intermittent" can be tricky to diagnose, but all amps have familiar pain points, namely internal connectors between circuit boards, and the points where the jacks solder down to the circuit board.

Unfortunately, the little GK combo's are a chore to disassemble. I've got one. And I have to say this: Don't open it up unless you're qualified to work inside mains powered gear.

Oh, and make sure it isn't your input cable.

Ric Vice · #3 10-05-2012, 05:28 AM

+1 I do seem to remember, that there have been threads on this before, so it might be worth it to do a search . I dropped one of my MB200's, when the shoulder strap on the bag slipped off, and it smacked the ground right where the transformer was bolted to the bottom of the cabinet. It crapped the transformer, and it had to be replaced. I think they quit mounting the transformer to the bottom of the case, or changed it's location when they designed the MBS models.

Ric

neddyrow · #4 12-02-2012, 02:19 PM

i am refreshing this thread so it is on the record as to what the problem was with my amp. very simple one: the direct out on the back panel had a broken lock nut and was replaced. works great again! don't ask me how that made the sound all scratchy but in case someone has the same problem with their GK and aren't afraid to open it up like i was, this will be one thing to check.