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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 21st Nov 2020, 8:32 pm   #41
DMcMahon
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Default Re: Uher CR 240 adjustments - operating point and hub tension

Forgot to mention that with external PSU at 20 volts, battery box connector contact I was 9.86V and I think off scale on the left VU meter after the 6.6V calibration.
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Old 27th Nov 2020, 1:08 am   #42
Uncle Bulgaria
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Default Re: Uher CR 240 adjustments - operating point and hub tension

With my PSU in place, contact I measures 9.6V for me, and yes, the VU meter whangs right over as it tries to test the 'battery'! Do your VU meters read differently? I've calibrated both to 0dB as required, but they register different values at the lower end of the scale, with the same signal input, as though they have different response curves. A minor irritation.

I've replaced the pinch roller with the new one that arrived from Hilmar Kreuger at Uher Service and it seems to have fixed the warbling problem. I've just recorded the entirety of a 45 minute tape side and it was steady all the way through.

The intermittent channel dropout I traced to a loose socket 301 on the amplifier board. I had to desolder it and pull it through the header housing to properly compress the contacts, but it seems to have done the job. A healthy dose of Deoxit got some grubbiness off as well. I may put the casing back on...!
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Old 27th Nov 2020, 11:06 am   #43
DMcMahon
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Default Re: Uher CR 240 adjustments - operating point and hub tension

Well done on fixing the warbling and drop out problems. I will have to have a look at that Uher service website.

I have not got to a position where I can check the VU meters. Still have to fix the Record switch contact arm (re-glue in correct orientation). Also still to replace the output amp IC's. Need to find/make time to do it, keep finding other things to do.

David
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Old 27th Nov 2020, 12:55 pm   #44
Uncle Bulgaria
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Default Re: Uher CR 240 adjustments - operating point and hub tension

I spoke too soon - on mains last night it was fine, but I put batteries in today and though they're well within the green zone on the VU meter, 'play' won't start the reels turning so it goes back to amber light mode as if it had sensed the end of the tape. Not enough roller pressure? Case off again...
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