Gentlemen . . . . .
On my # 45 almost to the end . . . .correctly amend . . . ..
" with that mere lifting of the C201 electrolytic coupling capacitor."
Change C201 to being C203 electrolytic .
Ref au #34
Sir Dorke sez
. . . . .
In order to verify which board is the source of the noise, I would do the following:
1. Remove C203 from the PA board(red).
(but . . . .BUT . . .BUT BUT BUT . . . the C201 which is shunting it, is still being left in the circuit. )
2. Listen to the noise both on the output and on the marked leg of R201(blue).
In case the noise appears only on the output , the PA board is the source.
In case the noise appears only on the leg of R201, the tone control is the source.
Ref au #39
Sir Kilgore Cemetery sez .
. . .
Connecting the negative side of my signal checker to the negative side of the cap and the
positive side of the signal checker to the base of TR303. The noise is there, but it's significantly quieter.
Also, a new development, there is significant noise on the left channel where the Phono input
connects to the Preamp (I think) Board. The noise there is loud even when the the noise at the
speaker connects is quiet. The red arrow is the noisy pin. This wire goes straight to the Phono Input
RCA jack. I re-flowed the solder on the Left, Right, and Ground pins both to the circuit board and to
the wires with no change
Ergo . . . .
We do have significant noise back at the post amp (or preamp circuit ), in accordance with the SETTING of the units FUNCTION SWITCH, with it still being able to get INTO the POWER amp via the still circuit existent C201 cap.
NOW . . . .
Sir Kilgore Cemetery . . .
Don your surgical gloves and break out your enbalming tools, as we are now needing you to perform a circuit component analysis / autopsy , with the principal point of contention being the C201 plastic family of capacitor.
My eagle eyes *** see the C201 capacitor as shunting the now pulled C205 electrolytic, vice, it having one of its leads being grounded . Reference to the Yellow Brick Road path . . . . or dots.
Alternate . . . . . removal of the incoming audio from the Power amp via the shown wire being lifted, and then confirm the minutes, hours that the left channels speaker is then silenced of that experienced Gaussian noise.
Foil Path . . . . Being All Blowed Up . . . . .
73's de Edd