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Revox MR8 PSU unstable
Revox MR8 PSU unstable
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Old 29th October 2017, 12:30 PM   #1
terremotor is offline terremotor  Spain
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Default Revox MR8 PSU unstable

Hi guys. I have a problem with the power supply of a small console Revox MR8.
When it has a circuit load, the -15v voltage drops slowly and is maintained at -13v. insufficient for adjustments.
See the PSU with LM337 regulator:
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Old 3rd November 2017, 03:54 AM   #2
anatech is offline anatech  Canada
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Revox MR8 PSU unstable
Hi terremotor,
Have you checked the supply for the -15V regulator? Use an oscilloscope to see if the regulator is dropping out. I find that the capacitors Revox used are failing right about now.

-Chris
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Old 8th December 2017, 06:39 PM   #3
terremotor is offline terremotor  Spain
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I have replaced some components. There was a bad rectifier diode.
I have also found some transformers with secondary open in preamplifier
I'm surprised, I do not understand why open transformer T100...
Studer Revox mr8 pre.jpg
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