[SOLVED] Power supply ps 305 d not work correctly

[erchiu]

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

 

[Relayer]

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



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:



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

 

[erchiu]

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

 

[erchiu]

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

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