My Sony TC377 won't record but plays ok.

[pjl52]

My problem: It won’t record. Neither does it appear to erase. Inputs seems ok as needles swing on meters, audio quality from the “source” is fine via headphone jack. Simply: when I record it leaves the previous recording on the tape untouched, with nothing new laid down. The record lights both go on.
I have doused the “record switches” with CRC to no effect so far. But getting the spray in the right spot is hard given how the switch is encased. I did take the small sheet metal shield off (which comes off with one screw)—so spraying has not been a shot in the dark. I reluctantly began trying to take the side panel off to get to the switches but have not finished that yet. I’d love to have electrical crude as the problem cause. If anyone can explain where the actual contacts are that would be great.

I write to ask if I am wasting my time on accessing those switches when the likely fault is the oscillator or other electronic component.

One thing is very strange though—A local guy on Craigslist recently was trying to sell the same model. I went over to put it through its paces—the only thing I found wrong was exactly the same problem I seem to have- in record mode, it did not erase or put a signal down. So I might be missing something obvious.
With thanks in advance,
Phil
Rochester NY

 

[audiojones]

Bias osc. power supply switch under the faceplate may be out of adjustment or dirty, preventing the 23 volts from the power supply from getting to the bias osc. board. The record indicator lights are fed from the lighting tap on the transformer so they’ll keep working even if the bias osc. board isn’t getting power. Switch 108 is a microswitch under the faceplate and whenever the linkage is in the forward mode the switch must be closed. Could be out of adjustment and linkage not pushing the plunger all the way in or could just be dirty contacts.

 

[pjl52]

Bias osc. power supply switch under the faceplate may be out of adjustment or dirty, preventing the 23 volts from the power supply from getting to the bias osc. board. The record indicator lights are fed from the lighting tap on the transformer so they’ll keep working even if the bias osc. board isn’t getting power. Switch 108 is a microswitch under the faceplate and whenever the linkage is in the forward mode the switch must be closed. Could be out of adjustment and linkage not pushing the plunger all the way in or could just be dirty contacts.
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SUCCESS Thank you AudioJones...a dousing with CRC Contact Cleaner solved the problem. I could not believe the fix was so easy. Note that the switch was physically making contact so my initial view was that contact problem could not possibly be the issue but it was! Thanks for helping me with this. Phil

 

[audiojones]

You’re very welcome and I’m glad you got it straightened out, these are great little tape decks IMO.