Working on Carver C4000 and could use some help

WOPL Sniffer

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#21
Unplug some of the boards and see if the short goes away and also check to see if any of the board connectors are off by a pin. These things are 2-easy to troubleshoot..
 

Dutch54

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#22
Remove all boards from mother board but the one that has the pot hanging off it, removed power supply/amp board and went completely through it and replaced any thing that was cooked or dead according to schematic. Put the PS back on the mother board and turned it on, lasted about fifteen seconds and fried the fuse. Anyone have any ideas for me on this, this damn thing is getting costly on parts. Took its temp right after in cooked the fuse and the 2200uF 25v caps were at about 180 degrees. Thank in advance for any and all help.
 

George S.

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#23
Can you run the power supply board on the bench, divorced from the mother board, and confirm it's DC output is correct and the unit isn't heating excessively?
 

Dutch54

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#24
Can you run the power supply board on the bench, divorced from the mother board, and confirm it's DC output is correct and the unit isn't heating excessively?
I did what you asked and it lasted about fifteen seconds and fried the fuse, but I got to test the jumpers that are 12VDC and they are real close to 12 volts. Took its temp right after in cooked the fuse and the 2200uF 25v caps were at about 180 degrees. Question: could the transformer power lines be hooked up wrong, there are two solid green and a green and with a yellow strip, which pad should the green/yellow be hooked too (#1, #2, or # 3 pad)? Again thanks in advance for any and all help.
 

George S.

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#25
Dutch, I think you've identified the problem area.
So get it working on the bench before you reinstall it.
I've never seen one of those preamps first hand, so I have no idea about wire colors.
However the Phase Linear manuals do give wire colors and connections for 120 VAC or 240 VAC line operation.
Perhaps the Carver owners or service manuals have similar info that will help.
Worst case you can ohm the transformer and figure it out.
 

Gepetto

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#26
What are you measuring on the +/-22V rails before the fuse blows? Is the bridge rectifier bad? Is the bridge rectifier installed backwards?

You should never have hot bulk capacitors unless the voltage rating is being exceeded or they are installed backwards.
 

Dutch54

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#27
What are you measuring on the +/-22V rails before the fuse blows? Is the bridge rectifier bad? Is the bridge rectifier installed backwards?

You should never have hot bulk capacitors unless the voltage rating is being exceeded or they are installed backwards.
Did not get a chance to measure on the +/- 22v rails before my last fuse went but have ordered some more. The bridge rectifier is new and put in according to the schematic and tested good.
 
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#28
What are you measuring on the +/-22V rails before the fuse blows? Is the bridge rectifier bad? Is the bridge rectifier installed backwards?

You should never have hot bulk capacitors unless the voltage rating is being exceeded or they are installed backwards.
Got the new fuses, moved the green wire with yellow strip to the #three pad what I believe to be the ground, tested the 22v rail test points and they tested 24v, no longer blowing fuses. Have not hooked it up to amp yet, will do that tomorrow to see if it works. Thanks for everyone's help.
 
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