Re: Sony Black Trinitron 24" with weird colour (pink)

Hello Peter, thanks a lot for your useful reply!

Without testing it I'd say its more likely a video drive problem, but
it might well be a crt fault. Its not falling crt emission, if it were
just that you wouldnt be getting green retrace lines. I'd measure the
voltages on all the non-EHT tube electrodes to see how the green
voltages compare to the other 2 colours. Also I'd measure the amount of
green drive vs red and blue. Tjis should tell you whether the prolem is
crt or video drive or other electrode voltages.

I have an oscilloscope. I will ASAP check differences in voltage for
all 3 colors in the CRT neck, right?

If the fault is the crt, you might be able to burn off an internal
short, if not its well & truly had it.

How can I burn an internal short?

If the fault is video drive, thats usualy fixable but not in every
case.

If its other tube electrode voltages, thats the easiest to sort out.

I will try to check if variations in screen voltage improves something.


There is also the final possibility of very low green emission plus
someone has unably tried to tweak the drive/background to comppensate
and has screwed those settings up. In this case the set would have very
slowly got pinker and pinker over time, so you should usually know if
is this or not. Low emission is easy to fix on most sets if you know a
bit about electronics.

I'm not sure of what you are saying... "Over time" do you mean along
days/months or along first minutes since turning on? What I have
checked is that the effect (green fault except when pure black)
diminishes along some minutes since power on. The effect is at its top
when powered on.


If youre not familiar with the dangers inside tv sets, learn first or
leave them alone. TVs and microwaves are the 2 household appliances you
really should not mess with unless youre upto speed.

All I know is I have to unplug mains, discharge capacitors, discharge
all HV from FBT to tube grid, and after some seconds try to discharge
again.

Is it reasonable to try to enter service mode in the OSD to tune some
parameters???

Thanks!



NT

.

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