I'm really good at it. I believe the cap was too close to the resistor, but I'm getting some funny numbers off my "Blue ESR " meter. In the mid 24uf paired and paralleled caps, I'm getting 765K on the Fluke in resistance mode and the ESR meter shows .01... Uf on the midcaps show right but why the extreme ohmage?
I'm really good at it. I believe the cap was too close to the resistor, but I'm getting some funny numbers off my "Blue ESR " meter. In the mid 24uf paired and paralleled caps, I'm getting 765K on the Fluke in resistance mode and the ESR meter shows .01... Uf on the midcaps show right but why the extreme ohmage?
The two meters measure this differently. The ESR meter should provide a pulse that does not charge up the capacitor and a "normal" Fluke multimeter when measuring resistance will provide a constant voltage - hence charging the cap. This may why you're seeing a delta between the two meters.
You want to measure the equivalent series resistance (ESR) of real capacitors so most ESR meters will apply a voltage pulse to the capacitor with the pulse duration less than what it would take to appreciably charge the cap so the voltage measured across the capacitor is due to the resistance drop - aka ESR. Most ESR meters have a selection range of discrete frequencies to test the capacitor at frequencies where it matters most. When the capacitor if fully charged the characteristics change and an accurate ESR value is not obtainable - as I understand it.
If you're measuring a big ass cap that was energized prior to making an ESR measurement - I'd say yes. The small ass caps I wouldn't worry about. The big ones take a while to discharge but the tiny ones not so much.
The soldere was gone off the post the autotransfomer was tied to also, so there was quite a few issues here. The wire was loose to the touch on one side..
What's the biggest poly you can get now? Something like 10 uF? Those will discharge quickly but all caps store energy - it's the discharge rate that is important when hooking up a meter to them to get a decent ESR reading.
The soldere was gone off the post the autotransfomer was tied to also, so there was quite a few issues here. The wire was loose to the touch on one side..
The root cause was too much f&^%$#@ power, but what to do about it. If I make this section bullet proof, what goes next. The resistors I'll go with something different but the caps may be my saving grace here....
Dennis, the big poly's I'm running in these are 24uf, 2 of them in parallel, 200 volters, bypassed by a 200 volt 2.2uf. The tweets are 2- 3.6uf 200 volters bypassed by a 200 volt 2.2 .
The root cause was too much f&^%$#@ power, but what to do about it. If I make this section bullet proof, what goes next. The resistors I'll go with something different but the caps may be my saving grace here....
Dennis, the big poly's I'm running in these are 24uf, 2 of them in parallel, 200 volters, bypassed by a 200 volt 2.2uf. The tweets are 2- 3.6uf 200 volters bypassed by a 200 volt 2.2 .
Damn - the current and resulting heat is taking these guys out. Which one(s) are getting cooked? You could go with higher voltage rated caps but can the speakers take it?
I'm not sure the caps are bad, they test good on the ESR meter, .01 or less and are spot on with the uf check section of the Fluke. The burnt one was too close to the resistor....
I'm not sure the caps are bad, they test good on the ESR meter, .01 or less and are spot on with the uf check section of the Fluke. The burnt one was too close to the resistor....
Will you use a heat sink for the thick film resistor? Maybe a bit more separation between the power resistor and cap will help. I wonder what temp those guys were subjected to? Had to be pretty hot to melt the solder and destroy the resistors and cap.