phase linear 400

George S. said:
You have a bad socket that's shorting to ground. They've far outlived they're as designed life span. Visit Glenn's Dual 500 thread and look at the new sockets he's using for building those beasts. Really nice!
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i will..but i ordered the backplanes from joe....
all will be upgraded....just wanted to see if i could find it...that socket answers a lot of previous qiestions....slowly but surely...
merry christmas mr. george...
 
George S. said:
Merry Christmas Gene! Why not WOPL a 8 fin and use the old parts on the 4 fin.
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merry christmas mr. george!!!
i will assemble the wopl...i have 3 places it can be installed....if that socket has been a problem since day 1...the 4 fin will be running soon...i have options...i love options...
.one thing i realized...never wopl without full comp...
a bad 50 year old socket can mess up your day...
the new wopl driver board would have solved nothing...without the back planes...
i have fun messing with the original...but i know i have one amp that not let me down....
soon to be two...lol
 
Gene
Merry Christmas

I had a bad sockets cause by me putting the the back fins on backwards, and it cracked the socket (Note- Now I always keep a couple bolt in so the fin cant move and rarely every take them out when replacing Output transistors which will help hold everything together and prevent stress on the socket and make it easier to install the output transistors since everything is set in place) The screw is the collector and the socket has a insulator going thought the sheet metal (you should be able to see it) so if it is cracked or missing it will or might short out or the collector after the bolt is installed the collector could also be shorted somewhere inside the amp, shorted to ground. Is this the woofer Amp? it will draw more current so temperature is always a factor and Heat might blow the transistor or crack the insulator because of Heat. (fans?)
I'm still one of the few here, who always use (Edit a another typo and getting better at it or spell check get me to lol Sorry but I hope you would have know what I meant Lol) mica insulators.
so how many output transistors were bad ?
 
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merry christmas music man...
merry christmas mlucitt...
yes...was woofer amp...i believe socket was bad since day i got it...difficult to get up and running originally also...
this time was 2 episodes...one when it quit and another implementing a repair...all together i think 3 or 4 left channel outputs and drivers and 1 resistor and 2 fuses..i spent many hours thoroughly searching....and narrowed it to putting screws in socket....will change it today...and see what happens...have 2 8 fins that need attention also...
i ordered a full comp wopl...will upgrade something...lol
 
the left bias is less than 200mv at idle....right side normal...
playing musice both left and right channels run between 400 and 500 mv....
i did change q8....d3 and d4 and a few resistors....
service manual has a procedure if the bias is too high...
but no mention of if the bias is too low...
i did not have a new q8....robbed one...
maybe tomorrow i will swap them around...
gotta be careful with this old stuff....if one thing get off kilter....
a lot of more stuff is fixing to get off kilter too....
just biding my time till joe gets time for my order....
i hope all of you did just fine this christmas day....
was very peaceful here....
 
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