Panasonic 36sx31e degauss circuit problems

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This set came in with a blown 6.3A fuse. I have no schematic but I
checked for any obvious problems and found none. So I replaced the fuse
with a 4.0 amp just to test it, (I have about 150 of this size in the
shop so I don't mind sacrificing a few). When testing the set, I
disconnected the degaussing coils (because they were too short to pull
the chassis out with them connected). I powered the set up and except
for purity problems it looked pretty good. It ran for about an hour and
then I shut it off for about 30 minutes before turning it back on
again. Again it came on fine and stayed on. I degaussed it manually,
disconnected power and plugged the coils back in. When attempting to
power it up this time it initially powered up, then I heard the degauss
relay click, I heard a loud hum from the degaussing coils and the fuse
opened. I then waited about a half hour, put a 6.3A fuse in and powered
the set up. It came on fine. I've connected a 10 amp meter in series
with the AC line and each time I've tested it after letting the degauss
thermistor cool down, as soon as the degauss relay activates it pegs
the meter for a very brief instant and then settles back down to
normal. It has not taken out the new fuse though. I know initial
current on degauss is high but how high is OK I'm wondering? Should I
just change the thermistor for good measure? I hate shotgunning things
but I'm not sure. And also I must ask as simple as this circuit is
should I perhaps suspect something else? Any comments or advice are
most sincerely appreciated. Lenny Stein, Barlen Electronics

 

[Rono]

I beleive there is a fuse problem with these units, where the degaussing
draws too much curent, just at initial startup. Try a "slightly" higher
fuse,
& I think you may have to replace the thermistor, & check back for more
posts attached to yours, to be sure. Rono.

 

[Art]

Actually there is a different degauss thermistor that is to be used when you
encounter the 'fuse failure syndrome in these sets. Also in Thomson and
Phillips sets, it seems the original degauss thermistor allows too much
current draw during the degauss cycle, over time the fuse just gives up. All
three manufacturers have notations regarding this problem on their
respective web sites, the cures, and part numbers required.

 

[Leonard Caillouet]

Where do you find it on the Panasonic web site?

The have a notation to replace the thermistor, but I can't find anything
about a different part.

Leonard

 

[Art]

"Unit is dead. Fuse F601 blows (black). Excessive AC current flow through
the degaussing coil. A change in the characteristics of D808 can cause
excessive current to flow through the degaussing coil and blow F601. Replace
D808."

Leonard: This is a copy/paste from Panasonic's Web Site. If you check the
new part supplied, maybe even with the same part number, you may find a
difference in type and parameters. Please post your in-depth discoveries
regarding this. Thanks!

 

[Leonard Caillouet]

Art,

I found the tip that you posted below, many times actually. The last time I
replaced a thermistor in one of the sets with that tip I found the new one
to be identical to the old one. That is why I asked. It sounded like you
actually had some info on a new type thermistor but it appears you are just
speculating.

The last time I talked to Panasonic on the matter they knew nothing of any
changes in the part. There has been a change in the part number, but as I
said, it was identical in appearance. I tried to verify if I was getting
the correct part and no one could confirm that there was a difference. The
best info that I got from Panasonic on the issue was to make sure that the
replacement fuses were time delay types.

I was hoping that you had some actual documentation on the parts. Your
original post made it sound like there was something on the site. In fact,
you were just making an assumption on the matter. Do you have some real
info from Thomson or Philips or are you just blowing smoke on that, too?
Some of us like to deal in real information, rather than speculation.

Leonard