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Old 16th Dec 2021, 10:22 am   #72
Phantomrose1999's Avatar
Join Date: Mar 2008
Location: Melbourne, Victoria, Australia
Posts: 261
Default Re: Grundig TK27 - Low audio output

Well, finally progress !! though not at the end yet.

1) Thanks to Lawrence for highlighting the speaker should be shorted, and sure enough the contact was not shorting it, done by previous owner who changed the belts. Slight adjustment of speaker shorting switch and its quiet until you press play.

2) As has been suggested here many times, i went over EVERY joint on the PCB, sucked out a few and put fresh solder for ones that looked like a blob, and then did the first wafer of the track selector switch as well, and its playing beautifully, So loud i can only run it at 3/4, its a beautiful and clear and loud sound quality.. just love it.

Bought a TK20 from the original owner yesterday and it came with 8 tapes, full of German music, and its incredibly clear and loud on the TK27.. i really cant believe the sound quality. (TK20 motor not spinning, ordered a 1.5uF motor run cap)

Back to the TK27, last problem is the record !! I have a magnificient bias signal at the erase head, and at the play/rec head, (about 130x volts at 54Khz) BUT the magic eye is not moving and the oscillator is not being modulated.

i may have caused this, when a wire on the lower right switch block came off, need to check where i soldered it onto.. Never had this problem originally.

Which switch would cause ALL input to not reach the EF86 ? given the magic eye is not even moving ? (phono, mic, radio..none)
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