Hi Friends

Can you please help clarify my problem. I am really confused.
I am trying to fix my atx smps.

The problem or confusion. Measurements on primary side.( hot side)
1) I place black probe of multimeter to negative of bridge rectifier and red probe to positive of main electrolyte capacitor and get a reading of 300v which I am happy.

2) However when I place black probe of multimeter on negative of electrolyte cap and red probe on positive of cap I get a reading of 24 v. (Same cap as no 1)

Is this normal readings regarding atx smps.

Thank you
Gasant

 

No,you may be reading across a different capacitor in the circuit, most ATX psu's have a split capacitor setup they are in series across the supply, so they can be used as a voltage doubler when connected on low voltages, similar to this diagram.

http://www.pavouk.org/hw/en_atxps.html