#1
How do I use a voltemeter to test the charge on the 500 volt capacitors on my Epi VJ? its a V3, and I can't get to the leads without taking off the board, and I don't want to take off the board with the caps charged! Also my multimeter has 2 different settings that say V, one has a solid line with a dotted line under it, the other has a wavy line, which do I use?
#2
Just connect the leads of the voltmeter to the leads of the cap (observe correct polarity!). The wavy line means AC and the solid line with a dotted line under it means DC. Simple.

Edit: Since you can't get to the leads, just wait about 30 minutes. There's a formula you can use to determine how long it'll take the caps to discharge, but I don't know it. It shouldn't take longer than 30 minutes, though (should only take 15 or 20, but just to be safe).
Last edited by Invader Jim at Jun 3, 2008,
#3
Thanks for the AC info, but now I feel stupid... how do I get to the leads on the caps with the friggin caulking/sealer stuff covering the bottem of the caps? I can't take the board off, can I?
#5
I'll have to unscrew it, is that OK? I guess I have to to discharge them anyways.
#7
The Voltohmeter is reading a big Zero, that is to be expected from a epi VJ V3 correct? It has been unplugged for 3 days, and it has those auto discharging resistors too. but shoulden't the VOM pick somthing up?
#8
You might want to apply some power to those capacitors to measure them. You're not going to see a steady measurement because they'll charge and discharge. Make sure you're using the DC volt check.
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#10
hmm...I think I'm having a brain fart. A cap tester or a multimeter with a capacitance check function would be ideal. Charge the cap up, ground your negative lead, and measure the positive end of the cap. If you have a hold function on your meter make sure you're using it or you'll just see a flash of numbers or the needle will peg to the right then drop, if you're using an analog meter.

Make sure your meter can handle it and be careful.
What you own is your own kingdom
What you do is your own glory
What you love is your own power
What you live is your own story
#13
If you can't get to the caps, measure the voltage from pin 1 or 6 on the preamp tube to ground.

After I've measured the voltage, I always short one of those pins to ground, just to be sure. Slightly unnecessary, but I'd rather get a loud bang and a big spark than sticking my hand in a live amp.
Last edited by mr_hankey at Jun 4, 2008,
#14
Quote by wanderingbudoka
hmm...I think I'm having a brain fart. A cap tester or a multimeter with a capacitance check function would be ideal. Charge the cap up, ground your negative lead, and measure the positive end of the cap. If you have a hold function on your meter make sure you're using it or you'll just see a flash of numbers or the needle will peg to the right then drop, if you're using an analog meter.

Make sure your meter can handle it and be careful.



What??? I think you are having a brain fart...
If you have a capacitance meter, DISCHARGE THE CAP BEFORE TESTING IT... you can wreck your meter otherwise

You'd also have to pull out one of the cap leads.
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#15
Quote by damirault
What??? I think you are having a brain fart...
If you have a capacitance meter, DISCHARGE THE CAP BEFORE TESTING IT... you can wreck your meter otherwise

You'd also have to pull out one of the cap leads.


You sir, are most definately correct. I must've been thinking about using an O'scope. Excuse my cerebral flatuence.
What you own is your own kingdom
What you do is your own glory
What you love is your own power
What you live is your own story