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Repairing a SMPS and I lost a component

datatrader

New Member
I was trying to repair a switch mode power supply for a Philips WACS700, and I suspected one of the zenar diodes was faulty. I desoldered it checked it with my MM and got distracted and the part went flying away. I lost it. Needless to say, I didn't get the details before it was lost. I found the schematics but there are no circuit diagrams for the supply. I am at a loss at what to do to replace the component. Can someone help me?

regards
datatrader
 

datatrader

New Member
Thanks for your reply. It's Z12. someone on another forum gave me the specs for the diode. 0.5W, 19V.

The next problem will be getting the specs for the inductor L2, unless I get an LC meter.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Thanks for your reply. It's Z12. someone on another forum gave me the specs for the diode. 0.5W, 19V.

The next problem will be getting the specs for the inductor L2, unless I get an LC meter.
Why would you need L2?, and how would an LC meter help?.

If you've lost that as well then you can't measure it, and if it's faulty then you can't measure it either.
 

datatrader

New Member
L2, is I suspect is the faulty inductor that is making the low frequency sound when the unit is on. The LC meter will allow me to find the most accurate replacement. There are no obvious schematics for this supply.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I just read your last comment about the LC meter. Do you have a better suggestion?
Is the supply fully working? - a noisey inductor shouldn't prevent it working. I would imagine a SMPSU would require any inductor replacing with the exact same type, as it's usually a VERY critical component (as the entire supply is designed around it).
 

datatrader

New Member
yes it's working, but the low frequency noise coming from the supply makes it unbearable. This happens straight after you turn the supply on.

And yes I do realize that it needs to be replaced with the same part, but how do I measure it's faulty and/or if there are no identifying marks?
 

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