Re: Grundig tk 24
[QUOTE=simpsons;1374144
Relay connection W1, from the schematic, either sends the record level to the magic eye on record or defeats the bias oscillator on playback.
Chris[/QUOTE]
From several different Tk 24 schematics I have checked I do not agree with the second part above.
From my Post 8 above I said that the Playback/Record relay W when de-energised connects the ECC 81 output through contact W1 to the EM 84 Magic Eye for record monitoring, this agrees with your "record level to the magic eye on record".
Note there also is a connection off to R8 which I think is the Record equalisation connection.
I also said that when the Playback/Record relay W is energised it connects the ECC 81output through W1 to the Playback equalisation components (connects directly to the junction of C10/R6/B2). I cannot see any way that W1 itself defeats the bias oscillator on playback.
The Bias Oscillator is enabled/powered by the +HT voltage supply being switched through contact D6 through to the Bias EL 95 valve (via closed contact B4). D6 is a changeover contact that when all the input selector push button switches are de-selected, D6 then switches +HT to relay W to energise it and puts the machine into Playback Mode. When any input selector switch is pushed down this changes over the D6 contact to de-enegise relay W (putting machine into Record mode) and as above switching the HT through to the Bias Oscillator.
I find contact B4 confusing as it appears to always be closed apart from when switched to Fast Rewind.
David
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