PL 400 Question?

nadude98

nadude98

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Got in the caps for the bridge rectifier and installed them.. rechecked everything and put it in my system. Damn it sounds good!!! Here's a lot of :love7: for everyone here!!!
 
nadude98

nadude98

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:happy3: That's the plan...! PL14_20 board is my next project. Just have to save up for it! My next question on that subject is about the options of going stock Quasi-Complementary or enhanced Full-Complementary. Why would someone go the stock way... Isn't enhanced full-complementary to best way to go?
 
nadude98

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:sad5: I was listening to Roger Waters new vinyl release of The Wall from his 2013-14 tour, when I got to side four the amp just died..... all the power went and it sounded like a barely playing blown speaker. Found the middle fuse was blown.. replaced and powered it up using DBT, everything seemed to be okay so I plugged it in without dim bulb tester and went to recheck the bias and really F'ed up, my hands and sight aren't what they used to be, the end result is I blew one of my outputs, plus a resistor R36 150ohm not sure what wattage. Not sure how to go about repairing this damage.

Took a pic of the outputs pulled, got them in styrofoam in the order they were on the unit. The sideways transistor is the shorted one...... Hope you'll forgive me, I know I'm kicking myself in the ass pretty good. :shock:

Any idea why I would have blown the fuse in the first place, I had it cranked but I didn't think it was that bad... It was the left channel fuse.. The output I ended up blowing is in the right channel..

outputs.jpg
 
Gepetto

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nadude98 said:
:sad5: I was listening to Roger Waters new vinyl release of The Wall from his 2013-14 tour, when I got to side four the amp just died..... all the power went and it sounded like a barely playing blown speaker. Found the middle fuse was blown.. replaced and powered it up using DBT, everything seemed to be okay so I plugged it in without dim bulb tester and went to recheck the bias and really F'ed up, my hands and sight aren't what they used to be, the end result is I blew one of my outputs, plus a resistor R36 150ohm not sure what wattage. Not sure how to go about repairing this damage.

Took a pic of the outputs pulled, got them in styrofoam in the order they were on the unit. The sideways transistor is the shorted one...... Hope you'll forgive me, I know I'm kicking myself in the ass pretty good. :shock:

Any idea why I would have blown the fuse in the first place, I had it cranked but I didn't think it was that bad... It was the left channel fuse.. The output I ended up blowing is in the right channel..

View attachment 23366
Click to expand...
One likely reason is you should NEVER have all MJ15024's in the quasi-comp config of a Phase Linear amp. Bottom row has to be RCA410 or SJ2741. Was the column that the failed device was in the column closest to the output binding posts?
 
nadude98

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Pulled the outputs from the other channel, 5 are bad. I'm wondering why all the output transistors are MJ15024's? I bought a kit from someone on Ebay about 4 years ago that replaced all the transistors from my PL14 board thru the outputs. They were supposed to be beta matched......
 
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nadude98

nadude98

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Gepetto said:
One likely reason is you should NEVER have all MJ15024's in the quasi-comp config of a Phase Linear amp. Bottom row has to be RCA410 or SJ2741. Was the column that the failed device was in the column closest to the output binding posts?
Click to expand...
No, it wasn't in that column. It was in the next one over. But like I said in another post there was 5 bad outputs in the last two columns.
 
laatsch55

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nadude98 said:
I think I shorted from emitter to collector with my lead....
Click to expand...

You just unleashed a lot of hate inside that amp.....I've done it myself....a LOT OF THINGS can be wrong now.....even on the driver board....
 
laatsch55

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nadude98 said:
Pulled the outputs from the other channel, 5 are bad. I'm wondering why all the output transistors are MJ15024's? I bought a kit from someone on Ebay about 4 years ago that replaced all the transistors from my PL14 board thru the outputs. They were supposed to be beta matched......
Click to expand...

The drivers (the bottom row) should have been something other than the outputs, preferably RCA-410's.....
 
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