Crossfire amp help please cfa-602

[Perry Babin]

Could you have two positive rectifiers on that side of the amp?

 

[joesch1999]

ok the the sockets are shorted together both came up as 0.000 touching the meter probes to the base and collector

 

[joesch1999]

this is with the transistors out of the socket what could be shorting them?

 

[Perry Babin]

Solder bridge, shorted driver transistor?

 

[joesch1999]

solder bridge is fine will check the driver

 

[joesch1999]

that was it driver transistor, could not find it because it only does it when power is applied, goes back to normal ten seconds after turning power off, what a pain in the butt lol thanks a million perry, perry just so I know is there a diode connected in that curcuit as well that could be causing the problem as well

 

[Perry Babin]

If you found a shorted driver, that could have been forcing it to go into protect. Have you determined if there is another problem yet? You'll have to reinstall all of the components to test it.

If you measured the DC across the emitter resistors, it should have shown that one or more had more than 0.000v DC if the driver was shorted.

 

[joesch1999]

yeah two of the driver transistors are shorting with power applied

 

[joesch1999]

well that was not it lol

 

[Perry Babin]

Did you try powering up the amp with no rectifiers?

 

[joesch1999]

yep still going in and out of protection and still wrong polarity

 

[Perry Babin]

With the rectifiers out of the circuit, there shouldn't be any significant DC on any terminals of the output transistors. The rectifiers are D121, D122, Q221 and D222 (I think, they're not clear in the photos I have). Are all of these out of the circuit?

 

[joesch1999]

yes there are none in

 

[joesch1999]

Perry can I pull the drivers out and power the amp? the c 1027's

 

[Perry Babin]

There's no reason to do that at this point.

Remove Q132 and the transistor behind it. Does the amp still go into protect?

 

[joesch1999]

yes it does, goes into protect with none of them in

 

[joesch1999]

I have all of the d718's out and the b688's out and still goes into protect

 

[Perry Babin]

Have you tried powering it up directly (no limiter) but with a 10 amp fuse in series with the B+ line?

 

[Perry Babin]

To clarify, Q132 isn't an output.

 

[joesch1999]

I have a ten amp supply that is regulated that I am using

wrote down the wrong number