Fishoz's PL 400 Conversion

[Fishoz]

Any verdict?

 

[laatsch55]

Not yet, working on it though......had to line out some hands for awhile. Got a big project going on tomorrow...

 

[laatsch55]

Joe says when a positive output shorts it puts positive rail voltage on the output, and the amp will try to regulate that output to 0 volts so it drives the negative output extremely hard. If the rail fuses don't go, the emitter resistors go...

 

[Fishoz]

TCB first.

 

[laatsch55]

Amen on that. I gotta go early in the morning with an 8 man crew. We'll have pics. Gonna pick up 2 400 bbl tanks, a 6 X 20 treater, a Lufkin 228 pumping unit, pad and gas motor. Gonna be a long day. all of this 90 miles outta town..

 

[Fishoz]

Thanks Joe.

 

[laatsch55]

That should not have occurred, well the emitter resistors blowing. When I blew the first 5 amp, I accidently replaced it with a ten....ergo the collateral damage. What bugs me is why did an output go with only 10 watts output on the frequency response test....a bad output perhaps??

 

[laatsch55]

R3 and R39 on the right backplane also toast...

 

[laatsch55]

And now showing a short between ground and the AC tabs on the BR....

 

[laatsch55]

Going to bed...5AM comin fast...

 

[laatsch55]

And now showing a short between ground and the AC tabs on the BR....

The secondaries....


I'd hate to think I toasted a 50 amp BR...

 

[laatsch55]

I unbolted the BR from the transformer bell, isolated the ground of the transformer secondaries from the BABB, brought it up on the DBT and checked input AC to the BR. 57 volts on each leg. only 3 tenths of a volt DC coming out of the BR on the DC tabs...

 

[NavLinear]

I unbolted the BR from the transformer bell, isolated the ground of the transformer secondaries from the BABB, and I still have a dead ground between the AC secondaries and ground...

Did you take out one of the reservoir caps?

 

[laatsch55]

Dennis, I edited my above post. I have no DC coming off the BR....toasted a BR....

 

[NavLinear]

That must have been quite the surge.

 

[laatsch55]

Yeah, enough to wipe out the emitter resistors...

 

[laatsch55]

The part I don't get is the output going at 10 watts output during a freq response curve...

 

[NavLinear]

Infant mortality maybe - just a guess though. I've read that ON does a good job of testing their semiconductors so...

 

[laatsch55]

Don't doubt that, but they don't test every one do they, just batch test??

 

[laatsch55]

Pulled the BR and the caps. Hooked them up temporarily on the bench. Then hooked the transformer to the BR. I have DC voltage...