rectifier board not working after putting on bypass caps.

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demogorgon

demogorgon

Member
Joined 2004
hello!

my rectifier board with 8 mur1520 diodes stopped working after i installed bypass diodes to take care of diode ringing.
I measure voltage into the board, but nothing out of it.

i put the caps in paralell with the diodes. they are 0.15uf 63V devices, polypropylen i think.
what have i don wrong? :cannotbe:

regards
marius
 
peranders

peranders

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Joined 2002
sjostromaudio.com
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... you don't guess, you have to know. Just measure! If you don't have experienced any smokeand blown fuses I'll doubt that you have broken the diodes. You carefully and nice have soldered in caps in parallel of the diodes and now nothing is working. You can actually use DVM and the "diode test" and check the diodes. You should get 0.5-0.7 volt in forward direction and much higher in the reverse direction, not necessarilly 1.999 if the bridge is connected.

You should also check you wiring.
 
M

Markje

Member
Joined 2004
If you connect a load, it will finfluence your measurement. If you measure diodes, the best way is to desolder them, otherwise, you should measure what peranders is saying, .5 to .7 in one way and something else in the other way (depending on the diode you are measuring).

Greetz Mark
 
demogorgon

demogorgon

Member
Joined 2004
Re: Re: rectifier board not working after putting on bypass caps.

peranders said:
... you don't guess, you have to know. Just measure! If you don't have experienced any smokeand blown fuses I'll doubt that you have broken the diodes. You carefully and nice have soldered in caps in parallel of the diodes and now nothing is working. You can actually use DVM and the "diode test" and check the diodes. You should get 0.5-0.7 volt in forward direction and much higher in the reverse direction, not necessarilly 1.999 if the bridge is connected.

You should also check you wiring.
Click to expand...
I know there are voltage on the inputt of the diode bridge.
no fuses blown as of yet. i do however use 10amp auto fuses, like the ones you find in on your main household wiering. they are nice to use when you don really know what to exspect.

Well, as i said, the diodes filter out ground at the very least, otherwise i wouldn't have much of a refference point for measuring voltage. and i know it works because i tested one pin to ground and the other to one of the phases on teh main wiering, and it was 135V as it always have been.

The wiering is checked, prepped and a-ok.


digi01 said:



before you installed bypass caps,what about the rectifier runing?
Click to expand...

it worked like a charm. my GC had been playing music for two weeks straight.

thanks for all the help and input guys!

cheers
marius
 
M

macboy

Member
Joined 2003
If you have no load and no filter caps connected to the rectifier, then the bypass caps will do just that... bypass the AC right across the diodes. If the caps are all the same in value, you have created a nice balanced 'wheatstone bridge' and you will measure 0 volts at the outputs. You need to load the output of the rectifiers so that current will flow through the diodes rather than just through the bypass caps!
 
demogorgon

demogorgon

Member
Joined 2004
macboy said:
If you have no load and no filter caps connected to the rectifier, then the bypass caps will do just that... bypass the AC right across the diodes. If the caps are all the same in value, you have created a nice balanced 'wheatstone bridge' and you will measure 0 volts at the outputs. You need to load the output of the rectifiers so that current will flow through the diodes rather than just through the bypass caps!
Click to expand...


You are totally right.

how humiliating..:sorry:

thanks for helpng me out here anyways.

cheers
marius
 
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