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Old 22nd Jan 2018, 3:56 pm   #1
Doris The Diode
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Default Levell PU33 PSU Fixed

Hi,

I wanted to share how I fixed my PU33 PSU/battery eliminator in my TD200DMP sig gen.
There doesn't seem to be any info or diagrams for this particular PSU, not that I could find so took some photos of the unit.

The fault was that one of the 150uF 40V capacitors had bulged and went faulty, which then gave me about +10V - 10V on the rails.
I replaced them both with four 330uF 35V capacitors, putting two in series to make up 165uF at 70V, close enough.

Please also find the circuit diagram below, off load values and on load values should you need to fault find.

The 8V2 zener diodes are behind the 9V battery connectors on the outside of the metal case.
The 1K2 resistor does get hot and my guess that it is around 3W in value.

I didn't measure the current drawn on the rails.

Cheers,
DD
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Old 26th Feb 2018, 10:26 am   #2
vinrads
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Default Re: Levell PU33 PSU Fixed

Well done with the fix, when I have a piece of modern equipment to repair I always check the capacitors in the power supply .Mick.
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Old 4th Mar 2018, 11:27 am   #3
Phil G4SPZ
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Default Re: Levell PU33 PSU Fixed

Thanks for sharing the story and the reverse-engineered circuit! Well done.
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