Palsonic TV doesn't degauss - posister stuffed?

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I picked up this Palsonic TV which seems to work fine except
for badly needing a degauss - blue in the middle to red in
the corners. Thought if I fix it it'll go in my parent's
holiday house...

It doesn't do the degaussing buzz on first turn-on, so I'm
assuming that the MX73 18 ohm posistor is rooted. I know
what's supposed to be inside these, but I don't know what
the cold terminal resistances should be - anyone? Guessing
I'll find 18 ohms somewhere ;-) In-circuit, I see 40 ohms
to one pin, just a couple of ohms between the other two.

How fussy is the TV likely to be - can I fit "almost any"
posistor and expect it to work? Where's the best place to
get one?

Clifford Heath.

Re: Palsonic TV doesn't degauss - posister stuffed?
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if everything else is ok, it would have to be this.
I havent had any problems using ones from other monitors of the same
screen size, but really rare to have one fail.

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I have seen 2 terminal devices (that look like big, thick disc
ceramics) used in place of these in more modern CRT monitors.

I assumed that they are one of those gadgets (I cant remember the name
- posiswitch maybe?) that were used in series with speaker leads and
would quickly go to a high resistance when a certain current was
reached, then reset when it was removed - for protection purposes.


WES components may have them.

Re: Palsonic TV doesn't degauss - posister stuffed?
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Download
http://www.wagner.net.au/catalogue/index.php?dir=&file03%_Television.pdf
from WES Components and see if it looks like any of the degaussing
thermistors on page 3-3.

If it does, probably the one in the catalog will work OK.



Palsonic TV doesn't degauss - posister stuffed?

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I had a "SONWA" 51" TV that had red portions in exactly the
same spots on the screen, very obvious when screen was
all blue on an empty station.

What I worked out is that you can place small magnets around the tube
at strategic spots that will remove the red spot
(ie turn blue, as seen on an empty station).

I managed to hot glue a bunch of small magnets above the
tube , and the colour tint has returned to what  it should be.

How is that for a non- electronic fix?



Re: Palsonic TV doesn't degauss - posister stuffed?
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   "Everyone" knows the best way to adjust gun alignment is to
remove the deflection coils from the tube neck and rap it smartly
with a 1Kg rubber mallet!.

Re: Palsonic TV doesn't degauss - posister stuffed?
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HEHEH :)

Some 30 years back my former boss (and self proclaimed "expert") tried
tapping the neck of a 26" black and white tube with a large
screwdriver to (hopefully) dislodge some screen phosphor material had
come loose and fallen into the guns, causing gun shorts, and a lousy
picture (can't remember the exact symptoms.)

This had happened after the set had somehow been laid on its back or
tipped backwards, and the customer wanted a "cheap" repair.

AS well as attempting to show us all how clever he was by doing this -
he seemed to find it exciting watching the "sparkles" as the tapping
dislodged some of the stuff, and the problem looked like it was
getting better but soon changed his tune when the glass neck suddenly
cracked, fireworks erupting in the gun assembly as it let down to air,
taking out the horizontal output transistor and (possibly- cant
remember exactly) damaging the power supply in the chassis also,
before anyone had time to unplug the set.

IIRC we had a spare tube from a junked set which wasn't too hard to
install (and probably should have probably been done in the first
place) , but there was a lot of time wasted in fixing the power
supply / Horizontal transistor which was not an easy job in that set.



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