Hi, I would like to enquire if anyone can give me some advice about a repair
I did for a friend recently.

The TV was a Philips 14PV182/05, which had a tripping powersupply.

I tested most of the electrolytics with my ESR meter, and supprisingly they
all read good.

I tested the HOT - good, but the set worked with it removed. (Sound + VCR)

I isolated all the secondary supplies derrived from the LOPT, but the set
still tripped (HOT in place).

So I presumed a faulty LOPT. This was confirmed by rudimentary ring testing
on my oscilloscope.


I replaced the LOPT with an HR equivilant, and the TV now appears to be
working fine. My question is, weather I should be looking for an underlying
cause for the original LOPT to fail. I did notice that there was some high
frequency sound coming from the TV (Audible with the TV volume turned right
down, and the cover off) - after I replaced the LOPT. This makes me wounder
if everything is A-Ok, but I'm aware that transformers / capacitors can
sometimes make some noise when running normally.

Do LOPTs just fail on their own, or are they usually 'caused' to fail by
another part? I've seen a cople of references to similar symptoms in this TV
(PSU tripping) being fixed by just replacing the LOPT.

Please note that I don't do this for a living or anything, I'm an electronic
engineering student, and only have a few years worth of experience fixing
the odd monitor / TV / SMPS etc. My theoretical knowledge isn't too bad (I
think), but I lack the experience of someone who comes across these faults
day after day.

Thanks for you help

Peter Clifton