17pw15-8 repair question

[tn245]

I'm doing a repair on this PSU. It seems these boards can either have Q809, or instead IC829 which is a 78L05 regulator.

According to the schematic the 17pw15-8 should have the Q809 BC548C transistor. The board I have is marked for Q809, but had a 78L05 installed in its place. It looked like original soldering, not someone else's repair attempt but I'm not sure about that.

So I'm confused, should I replace with the 78L05, or with the transistor?

[tom66]

Re: 17pw15-8 repair question

You should check to see if a zener and resistor are installed connecting to that middle ground pin. If not, and the ground pin is grounded, then use a 78L05. Otherwise, use the transistor.

[tn245]

Re: 17pw15-8 repair question

Thanks! There's a low value resistor (~0.2R) instead of the zener connecting the middle pin to ground. The other resistor R851 is not installed. So it looks like the 78L05 is the one to go with then.

[elviramjw]

Re: 17pw15-8 repair question

just for reference the posted circuit diagram is WRONG
ic802 is shown as a IRF7314 (FET) IT IS NOT A FET
it is a L6562D http://uk.farnell.com/stmicroelectro...?ref=lookahead
There are people selling repair kits such as Ohms.... & Char...H&S who state they supply the IRF7314

[tom66]

Re: 17pw15-8 repair question

Yep this is pretty common on Vestel schematics - they will use a footprint that matches, even if the part # is completely wrong!