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Analog board with Voltage too low then too high

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I have been busy this week with a Classic II A/B.

 

Voltages were too low on the first place, so manage to replace the usual caps, but they remain low after the replacement.

 

On a second try those were far too high (5 volt was 6.25 v and 12 v around 12.2)

 

Any idea ?

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Did you adjust it? There should be a potentiometer:

 

post-2640-0-06723300-1449508895_thumb.jpg

 

Let's start there...

 

If you can't get a good result you can try to resolder PP1 and then replace the Optocoupler

Edited by 360alaska

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Update,

 

Replaced the Optocoupler yesterday, and apart from a first boot when a cap bursted open (i realised i fitted it the wrong side) the AB board is working again.

 

Some weldings were a bit weak, and after touching those up, voltages are fine ans steady.

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