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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 30th Jun 2020, 5:11 pm   #61
Walkmann
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Join Date: Jun 2020
Location: Marlow, Buckinghamshire, UK.
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Default Re: Sony WM-D6C dc converter

OK so have done some more digging and taken some readings on Q601 and IC601.

In play BCE at Q601 are 5.3v, 6v, 6v

In play the pin voltages on IC601 are going from pin 1 to 16 are:
1.2v, 1.2v, 1.2v, 0.35v, 1.6v, 1.24v, 4.2v, 6v, 0.2v, 0v, 0.2v, 0v, 0.2v, 0v, 5.4v, 0v

the readings do not seem to correlate to the voltages in the service manual although reading other posts the manual could be wrong; however, I have to assume IC601 is faulty and will need to be changed?
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Old 30th Jun 2020, 5:14 pm   #62
Walkmann
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Default Re: Sony WM-D6C dc converter

and just to add the speed control on manual makes no difference at all as does adjusting the on board pots RV601,603. The coil wires seem fine
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Old 30th Jun 2020, 7:53 pm   #63
Mooly
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Default Re: Sony WM-D6C dc converter

The transistor voltages sound reasonable but it would still be good proof to isolate the base and confirm the motor ceases to run.

The voltages on the chip... its hard to say. Some of your readings seem more in line with what I would expect compared to those in the manual.

For example pins 2 and should be at the same potential based on the internal chip block diagram and opamp theory... in other words just as you measure, and yet other readings seem off.

I guess swapping the chip acts as 'proof' one way or the other.
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Old 5th Jul 2020, 12:04 am   #64
Walkmann
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Default Re: Sony WM-D6C dc converter

Ok, so have swapped the chip, checked all the wires and it now operates as intended, seems the right speed, it plays and records fine - it works!

Will check the speed later but am now satisfied that together we have rescued a walkman that had been stored and somewhat neglected

thanks to you all.
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Old 5th Jul 2020, 7:20 am   #65
saxmaniac
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Default Re: Sony WM-D6C dc converter

Brilliant, you got there in the end!
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Old 5th Jul 2020, 7:56 am   #66
Mooly
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Default Re: Sony WM-D6C dc converter

That is good news.
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