8 Oct
2001
8 Oct
'01
2:55 p.m.
Tony Duell skrev:
> >No, that's the deflection yoke. The
flyback transformer is on the PCB
> >normally. The easy way to find it most of the time is to follow the EHT
> >cable from the flare of the CRT back to a plastic-encased lump on the
> >PCB. That's normally the flyback transformer (it could be a voltage
> >multiplier in some older colour monitors, but I don't think that's an
> >issue here).
>
> All right, I stole some sticks of hot glue from the scale modellers and
> poured it onto the thing which looks like this:
The place to put it is between the ferrite core and the
block containing
the windings (with all the connecting pins on the bottom)
IOW, between the big block and the little handle? That was hard to reach.
> ,-----------.
> | _ |
> | | |WARNING|
> | | | HIGH |
> | | |VOLTAGE|
> | | | |
> |_| |_______|
>
That looks just like a flyback transformer :-)
It looks like a kettle to me. =)
> Then I let it dry and turned it on. Still the same
horrible sound. I walked
> around the thing for a bit, and it seemed as though the noise emanated from
> the black cage containg what is probably the mains transformer.
Sounds like a switch mode PSU. Any transformer can
vibrate, such as the
one in the SMPSU circuit. Now, it should oscillate at an ultrasonic
frequency so you won't hear it, but dried up capacitors in the SMPSU
circuit can make the thing drop in frequency, sometimes with no other
effects...
The old dried up capacaitors problem...
If you can get an ESR meter (and IMHO if you repair
monitors or SMPSUs
you _need_ some way of measuring the effective series resistance of
capacitors) then you could test all the electrolytics in the power supply
section.
I don't intend to take up high-voltage repairs as another hobby of mine. I'm
too intent on keeping on living with all my bodily functions intact.
--
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