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Trace Elliot Commando 10 troubleshooting

PostPosted: 03 Apr 2017, 03:08
by pervyinthepark
Hello, I'm trying to help fix my roomies bass combo amp, pictured in the link below.

Honestly can't figure out how to open this with all the wires. I can unscrew it from the top but then I cannot wiggle the amphead part free because the wires inside are too short. Is there something I'm missing about opening these kinds of small combos?

Re: Trace Elliot Commando 10 troubleshooting

PostPosted: 03 Apr 2017, 18:54
by alexradium
i guess you have to remove the front grill,the speaker and detach the wires from it,then you should be able to slide out the chassis

Re: Trace Elliot Commando 10 troubleshooting

PostPosted: 03 Apr 2017, 21:41
by pervyinthepark
I managed to slide it out, turned out the problem was a piece of covering unraveling covering on the inside. I guess I was too fatigued to figure that one out last night when I finally got around to it... I got it opening now and partway out but the problem in taking it all the way out now is the speaker cable, the metal clamp of which is super tight. Any idea how to untighten it?
Sorry if I'm noobie, only amps I "worked" on so far were Peaveys that we basically just opened and put back to find it was dirty pots (lol).
Heres new pics
The amp was doing the thing where it "pops" and the volume sort of tremolos with it after playing for a while. Before that it essentially worked but would become too quiet to play after about a song or two.
I'm looking for damaged components, hoping it would be easy to spot like a popped capacitor :lol: but I don't see any signs so far.
It looks like there is thermal paste, poorly shit upon TWO of the FOUR, I'm assuming power regulating, components. I hope I don't have to deal with that :(

Re: Trace Elliot Commando 10 troubleshooting

PostPosted: 04 Apr 2017, 21:55
by pervyinthepark
I got the uncovered metal wire off but the green one seems like they covered it so you can't undo the tab on it... >.<

I tried testing the voltage regulators with my multimeter and just got 0s with it off or on! Although maybe the fuses on my multimeter are blown.

Re: Trace Elliot Commando 10 troubleshooting

PostPosted: 13 Apr 2017, 01:17
by pervyinthepark
Hi!! :D :D
I hope I didn't scare everyone off seeming incompetent!
I got some time and confidence and got the circuitboard all the way out! It now seems clear where the fault may be - a resistor is completely burnt up! I'd take pictures but it seems pointless, you could google it lol
Anyway, I should probably just replace the resistor but before I cut it out and replace it (seems easier to do it that way in this case because the board is effectively bolted to the chasis so I can only access the top without stripping out the bolts) but I'm wondering if I can prevent this sort of thing from happening by upping the value or wattage rating of the resistor! Here's schematic - ... nload.html

The burnt resistor is #R35, a 4R7 1W. I notice most other resistors around the power amp are 2.5W. Is it possible that the low watt value of this resistor made it prone to failure if the input is too high or something?