PL400 glad I found this forum.

GaryCooper

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X usaf electronic tech.
#24
Well like a wise man said look at the bottoms for discoloration ect..
Three of my 327s were bad but I only bought 2 got 2 more otw last component on my left side checked every trace in question every junction on both sides at least for comparison then got to Q10L following traces. IMG_20230507_211049951.jpg
 

GaryCooper

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#29
.was like christine...they couldn fix it...and probably did a lot of damage trying...then sold on the bay...
mama said there would be days like this...she just did not say they would come in bunches like bananas....lol
My parts are from fleabay but I bought this unit 4 years ago ran fine till left channel fizzled out That is when I started troubleshooting. So someone must have done ok on repair it did last 4 yrs.
 

GaryCooper

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X usaf electronic tech.
#32
understood....
i still have a bad taste in my mouth from christine...
lol
get a protection board...
you are lucky you didnt get the speakers...
Gene where do I get the protection board? I see different ones . What's the best deal on this unit? I'm sure after I replace Q10L she should fire up so I can start testing . At least I hope.
 

gene french

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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
#33
Gene where do I get the protection board? I see different ones . What's the best deal on this unit? I'm sure after I replace Q10L she should fire up so I can start testing . At least I hope.
the ones i have are direct bolt in...they can be purchased at www.wattsabundant.com...
they are light years ahead of those cheapies out there....
buying from the website is cheaper than ebay....he has his listed there also...
keep me up to date...i am very interested....
and remember...you cant really fail....you can always at any time get the white oak stuff...
but, i do understand so much the challenge of figuring it out....lol

win/win/win....

as other members say....
not a wife friendly hobby....
not a cheap hobby either...

i remember seeing my first one...in college....i was sooooo jealous...
lol
kinda went crazy when i found this group...i have a bunch now...
lol
i started out seeking help on my sx1080....looked here and audio karma...
everyone was so nice here...and soon had it whipped....
i "rediscovered" that long lost pl400 feeling...
lol

good luck!!!!
 

gene french

Veteran and General Yakker
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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
#34
Gene where do I get the protection board? I see different ones . What's the best deal on this unit? I'm sure after I replace Q10L she should fire up so I can start testing . At least I hope.
if you hook up speakers before you get the protection board....at least put like a 1 or 2 amp fuse on the path to the speakers....
in series...they wont let you play too loudly....but the will protect your speakers to a point...
testing with no speakers attached is ok.....
and when you adjust the bias...after the amp is performing....
get off of the dim bulb tester...
 

GaryCooper

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Location
South Central VA.
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X usaf electronic tech.
#38
Gene with this forums help i have solved my christine left channel what i did was matched up two sets of Q1.2 & Q3,4 (like someone has been telling me most of the way through this repair) which gave me output however positive half was AFU ,removed d9,10 lead boom clean signal. Replaced Q8,9 reattached leads checked both channels clean signal with DB on dim im clipping PP 100v (approx) positive half clips about 4 v before neg half on scope it will make a nice square wave lol. pic on my phone of my work.
 
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