24-11-2014, 09:58 AM
There's a whole bunch of possibilities here.
For the 60V rail, check the feedback resistors 2R36 & 2R37 - they need to be spot on - C11 & C14 should almost certainly be replaced - particularly C11 as if that is failing, high ripple would be a symptom.
Its also possible that ripple is being injected from the 120V rail which is basically a second (unregulated) capacitively isolated 60VDC supply added to the base 60VDC line - check 2C10, 2C13, 2C15 & 2C67 along with its feedback resistor, 2R31 - any shorts or problems with 2C10 or 2C67 and the 60V rail would be in a world of pain... Is the 120VDC line clean? It will have all the rubbish from the 60V rail superimposed anyway, so is it noticeably worse or much the same?
Need to check each DC level against the schematic - if you could write on the schematic the measured voltages in red or similar and post that, it would help a lot...
For the 60V rail, check the feedback resistors 2R36 & 2R37 - they need to be spot on - C11 & C14 should almost certainly be replaced - particularly C11 as if that is failing, high ripple would be a symptom.
Its also possible that ripple is being injected from the 120V rail which is basically a second (unregulated) capacitively isolated 60VDC supply added to the base 60VDC line - check 2C10, 2C13, 2C15 & 2C67 along with its feedback resistor, 2R31 - any shorts or problems with 2C10 or 2C67 and the 60V rail would be in a world of pain... Is the 120VDC line clean? It will have all the rubbish from the 60V rail superimposed anyway, so is it noticeably worse or much the same?
Need to check each DC level against the schematic - if you could write on the schematic the measured voltages in red or similar and post that, it would help a lot...
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