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[SOLVED] Power supply ps 305 d not work correctly

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erchiu

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hi everyone,
from this morning my bench power supply (ps 305 d) it does not work correctly.
the output voltage is without regulation and it is to maxim (32 volts).
on web i found a diagram similar but my power supply have some different.
the diagram have an lm324 (u104) and another ic (u105) that i don't know (think another op-amp)
while on my board there are four ic.
two of these are lm 301 an , but other two i can not see the label.
i attach the schematic that i found and the images of my power supply.
thank you so much for any suggestions
erchiu
 

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Re: power supply ps 305 d not work correctly

Hello erchiu,
Do you live close to the sea or coastal area?
The reason I ask is due to some of the component legs from your photos
showing what looks like rust. See modified picture below

Rusty Legs.jpg

You really need to give "ALL" the PCB's a close visual check of components
as well as solder joints for any defects. Solder any joints that may look
suspect. See modified picture below:

Solder Side - Joints.jpg

The arrow pointing to a joint looks suspect to me. You may find others,
especially around heavy current areas.
Please let us know what you find.
Regards,
Relayer
 
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    erchiu

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Re: power supply ps 305 d not work correctly

Ok,
i try to replace all the defective welds and i try again the bench power supply
 

I have replaced the two 2n3055 mosfet.
Now is ok.

- - - Updated - - -
 

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