repair SMPS with part No. HF100W-SB-13.8.

[sanjay76]

Hi,

I am trying to repair SMPS with part No. HF100W-SB-13.8.

This SMPS can give O/Ps in two ways- first when connect AC mains to it (which is working fine i.e we get the required O/P when we connect AC mains to it)secondly when battery is connected it should give the required O/P (which it is not giving).

P.S.

1) I dont have schematics of this SMPS.
2) Was not able to find data sheet of Transistor with marking on it as "K 940".
3) This SMPS comes in two types - one in which two separate comprators (part No. LM393) are used and secondely in which one comparator (part no. LM393N) is used.
4) The problem is found in only SMPS having two comparators.

Please advise.

 

[Nigel Goodwin]

2) Was not able to find data sheet of Transistor with marking on it as "K 940".

Try looking under it's full number - 2SK940 - plenty of datasheet hits.