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Need some help with this Kustom 100

S

superquick

Dec 6, 2011
144
1
west ga
#1
I recently played a set with my gospel group at a church and the bass player/pastor for the church said he found this head in the basement while he was cleaning out a room to make himself an office. He said he hadn't even plugged it in to see if it worked because it was in his way so he gave it to me. I did some looking on google and I can't seem to find this particular model. It's a Kustom 100 4 channel pa head with a spring reverb unit in it and the closest thing I could find is the Kustom 200. If anyone could give me some more info on it I would greatly appreciate it.

I plugged it up and nothing happened so I pulled it out and started checking the resistance of parts starting with the on/off switch. The switch shows resistance when in the on poistion but the capacitor that grounds the switch to the metal box doesn't. I googled a bit on the particular capacitor and can't seem to find the exact one that is in the amp. It's a Paktron 150vac mvl.

So my question is: given the info above, does it sound like the capacitor is bad and would that be causing the amp to not power up? And if so, Does anyone recommend where I could find a replacement?

pics for reference

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Thanks you guys
 
#3
The cap to ground should NOT have resistance (more correctly should have infinite resistance) . That is the AC grounding cap, caps block DC (like from your meter) and pass AC. The switch should read very close to zero resistance but could still be faulty under the load of the amp. Have you checked the fuse yet?
 
#4
Sorry but this is an amp that should be given to a good tube tech to check out. It certainly should be powered up slowly using a variac or a ballast box. Almost certainly it will need to be recapped at a minimum. Just plugging the unit in could well lead to a cap blowing in a nasty way. It will need time and patience to bring it back to its former "glory".
 
#8
B-string said:
The cap to ground should NOT have resistance (more correctly should have infinite resistance) . That is the AC grounding cap, caps block DC (like from your meter) and pass AC. The switch should read very close to zero resistance but could still be faulty under the load of the amp. Have you checked the fuse yet?
Click to expand...

That was the answer I was looking for. I wasn't sure if it would show resistance or not, so that probably isn't the problem then. I used the meter to check the fuse and it shows resistance so I would assume that it's still good. It's soldered in so I hope it is. How would I check the switch under load? Plug it in and then check the resistance?

And yes, it is all solid state. No tubes, which is pretty surprising considering its age.
 
#10
First know as BassmanPaul pointed out, that if you do manage to get power to it the electrolytics have been drying out for many years. They could very well short turning that into a piece of burnt scrap?

You would have to do a voltage drop test on the switch. This means your meter (and YOU) will be working with wall voltage. Are you well enough trained to deal with high voltages?
 
#11
I asked my dad to lend a helping hand so I wouldn't hurt anything (or myself). We started with the power cord and went through the circuit to check for any breaks. He works on electric scissor lifts and such so he knows more about electricity than I do. We found nothing that seemed out of place though. I'll have to do more research on it I suppose
 
#12
#13
Next, disconnect the AC cord and find the power transformer primary wires (that would receive the wall power) check those for resistance, if they have a pretty low number check the secondary wires coming out of the transformer (you should un-solder one wire to do this). If you still get low numbers the rectifiers could be open (they usually short but I have seen open ones as well).
 

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