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CTC185, what's a safe way to start it ?

M

moonlite

Jan 1, 1970
0
Hi- I have a CTC185AB4 chassis. The 5 amp. fuse was blown, the HOT was
shorted as well as the regulator Q4114. My testing of the Flyback is
inconclusive. I installed the regulator kit, but I'm afraid to turn it
on and blow everything up again in case the Flyback is bad. Can anyone
suggest a safe way to test the set without losing all these parts I put
in ? Will turning it on at a reduced AC voltage do the trick ? Thank
you

moonlite
 
J

James Sweet

Jan 1, 1970
0
moonlite said:
Hi- I have a CTC185AB4 chassis. The 5 amp. fuse was blown, the HOT was
shorted as well as the regulator Q4114. My testing of the Flyback is
inconclusive. I installed the regulator kit, but I'm afraid to turn it
on and blow everything up again in case the Flyback is bad. Can anyone
suggest a safe way to test the set without losing all these parts I put
in ? Will turning it on at a reduced AC voltage do the trick ? Thank
you

moonlite

Wire a 100W lightbulb in series with the set and turn it on. The bulb will
limit the current.
 
R

RonKZ650

Jan 1, 1970
0
I hope you've checked the picture tube. A lot of 185s with the old "no
vacuum in the picture tube, shorting multiple parts trick."
 
J

John-Del

Jan 1, 1970
0
Can anyone
suggest a safe way to test the set without losing all these parts I put
in ? Will turning it on at a reduced AC voltage do the trick ? Thank
you

I've had a lot of these (with 25 or 27" tubes) start normally, then arc
from the top of the flyback to the core, immediately smoting the HOT
and regulator.

I think on these chassis you can jump the regulator out and run it on a
variac to give approx B+, and use a sacrificial HOT from a junker. If
it blows the horiz out again, it won't damage the regulator. If it
runs, try waving a HV probe around the top tower of the flyback to see
if you can draw an arc. If you can locate the pinhole, you can RTV it
shut. There should be more than enough room between the tower and core
to insulate it.

John
 
K

Ken Weitzel

Jan 1, 1970
0
John-Del said:
I've had a lot of these (with 25 or 27" tubes) start normally, then arc
from the top of the flyback to the core, immediately smoting the HOT
and regulator.

I think on these chassis you can jump the regulator out and run it on a
variac to give approx B+, and use a sacrificial HOT from a junker. If
it blows the horiz out again, it won't damage the regulator. If it
runs, try waving a HV probe around the top tower of the flyback to see
if you can draw an arc. If you can locate the pinhole, you can RTV it
shut. There should be more than enough room between the tower and core
to insulate it.

John

Hi...

Just from curiousity, John, why not rtv the whole durned
flyback on general principle?

Take care.

Ken
 
M

moonlite

Jan 1, 1970
0
Thank you for this very good info ! There seems to be a small hole on
top of the Flyback with lots of burn marks around it. I think a new
Flyback would guarantee a permanent fix. Has anyone used RTV without
getting call backs ?

moonlite
 
A

Art

Jan 1, 1970
0
IMHO: Replace the LOPT if indeed you found an arc point perforating the
covering. In my experience, once this happens and there is even a slight
residue of the carbon tracking it will fail again. Only absolute sure way to
repair will be to replace the component. If it were my own set and I would
sacrifice the time and parts to test the RTV issue, may even try it.
However, for a paying customer, replace the LOPT.
 
M

moonlite

Jan 1, 1970
0
Thank you so much ! I think that's what I'll do. These parts aren't
expensive these days after all.

moonlite
 
M

moonlite

Jan 1, 1970
0
Thank you so much ! I think that's what I'll do. These parts aren't
expensive these days after all.

moonlite
 
M

moonlite

Jan 1, 1970
0
Thank you so much ! I think that's what I'll do. These parts aren't
expensive these days after all.

moonlite
 

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