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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 16th May 2022, 12:47 pm   #21
DMcMahon
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Default Re: Philips 4307 - Playback issue

A very good call from Ben reference the drive belt being on the pulley 60Hz step.

David
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Old 16th May 2022, 12:53 pm   #22
ben
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Default Re: Philips 4307 - Playback issue

Thanks David. I learned that by accident in the early 1990s when working on an old ST451 which used a very similar chassis!

The crackling may well just be the volume pot, possibly the rec-pb multiway swtch (but these in my experience don't tend to give trouble on the N430X, unlike with say the Tandbergs) but if the sound cuts out then the germanium transistors and/or driver may have tin whiskers. Isolating these on a separate heatsink usually works at least in the short term. But maybe I'm jumping the gun.
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Old 16th May 2022, 1:09 pm   #23
eddfriz
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Default Re: Philips 4307 - Playback issue

Quote:
Originally Posted by ben View Post
Thanks David. I learned that by accident in the early 1990s when working on an old ST451 which used a very similar chassis!

The crackling may well just be the volume pot, possibly the rec-pb multiway swtch (but these in my experience don't tend to give trouble on the N430X, unlike with say the Tandbergs) but if the sound cuts out then the germanium transistors and/or driver may have tin whiskers. Isolating these on a separate heatsink usually works at least in the short term. But maybe I'm jumping the gun.
The sound does cut out when adjusting the volume control so will try electronic contact cleaner as David suggested but if, as you say, it's the germanium transistors and/or driver than I'm rather lost of none of that makes any sense to me unfortunately...
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Old 16th May 2022, 1:57 pm   #24
DMcMahon
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Default Re: Philips 4307 - Playback issue

Yes the old Germanium transistors potentially having tin whiskers gets more difficult unless one can identify the problem transistors and replace them.

At the same time as giving the volume control and heads a clean, also would be worthwhile spraying the contacts of the Record/Playback switch then exercise the switch many times using the Record button just to be on the safe side.

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