Maybe if you tie up the Pass Master or Eric Lauchli and tickle their feet with a feather for a few hours.
(or ask Steve Jensen Eddy if he managed to borrow it from Lauchli)
(or ask Steve Jensen Eddy if he managed to borrow it from Lauchli)
Got a Fet One today. Seems to have a defective Power Supply.
(A Lot of Transistors MPSA92, MPSA42, MPS6571, FPN4250A, FT317).
Output signal is not symmetric, same on both channels.
Has anybody the schematic?
😕
Thanks,
Gerhard
(A Lot of Transistors MPSA92, MPSA42, MPS6571, FPN4250A, FT317).
Output signal is not symmetric, same on both channels.
Has anybody the schematic?
😕
Thanks,
Gerhard
if that drek is in my workshop , I would find what's the culprit - without asking and replacing everything .....
that's just plain and simple preamp .......
edit:
with "everything" I meant on everything in PS section ; it certainly needs recap after all those years ....... and you have - what - few more parts , except caps ...
that's just plain and simple preamp .......
edit:
with "everything" I meant on everything in PS section ; it certainly needs recap after all those years ....... and you have - what - few more parts , except caps ...
Did that already.
Found 4 completely shortened and one partial shortened.
Want to understand what happened and to avoid it happen again.
And of course what's the sense of it at all......
Is it sooo hard to understand, why I'm trying t reach a schematic?
😎
Found 4 completely shortened and one partial shortened.
Want to understand what happened and to avoid it happen again.
And of course what's the sense of it at all......
Is it sooo hard to understand, why I'm trying t reach a schematic?
😎
happy hunting ;
I hope someone will chime in with needed schmtc , so we can help you in easier way
I hope someone will chime in with needed schmtc , so we can help you in easier way
Going to order the defective parts (or replacements).
When replacing these I try to draw the schematic (have to pull the pcb out, didn' that already...).
And hope they will not blow up again....
🙄
When replacing these I try to draw the schematic (have to pull the pcb out, didn' that already...).
And hope they will not blow up again....
🙄
Why?
Nominal capacitance 1.5 mF, measured 1.9/2.0 mF.
Typical ESR 170 mOhm, measured 120/130 mOhm.
Same advice as "change everything"?
😀
Nominal capacitance 1.5 mF, measured 1.9/2.0 mF.
Typical ESR 170 mOhm, measured 120/130 mOhm.
Same advice as "change everything"?
😀
BTW:
Pulled out the pcb an found shortened B-E on several transistors by the soldering side layout.
So they are not defective. Only three were gone....
🙄
Pulled out the pcb an found shortened B-E on several transistors by the soldering side layout.
So they are not defective. Only three were gone....
🙄
well - you must confess that novice ( who is asking for schm of simple preamp ) isn't supposed to have ESR meter .... and I couldn't know in which condition they are .....
so - to rephrase my self - for proper repair of preamp - replace all broken parts .....
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