Last-Ditch effort on Sony PTV

C

Chris F.

Guest
After several more days of fruitless labor, including successful cleaning
and coolant refill on all 3 CRTs, I am finally at a dead end on this thing.
If you haven't seen my last couple of posts, this is a Sony model KPR-36XBR
projection set. It originally had severe high voltage arcing around the
anode caps. I blew around 7-10 HOTs before finally stopping the arcing - by
replacing the CRACKED anode connectors and completely sealing the new ones
in with silicone. But now the HOT would overheat if the HV was connected to
anything. I disconnected the HV and it only measured 10kV. After some time,
I discovered that the focus/rectifier section of the flyback was smoking
hot. It was now obvious that the HV rectifier had shorted, and was applying
raw AC to the three CRTs, thereby causing an overload.
I could have screamed!! I guess all the arcing did the flyback in. There's
only one thing that will save this set from the trash now - if some generous
soul on this NG has a good used one that they'd give or sell me for a
reasonable price. Part #, by the way, is 1-439-366-12. Discontinued by Sony.
Otherwise, the next guy to get his hands on this set will be the trash
collector. I may save the CRTs as they are now in fairly decent shape (good
emissions, no phosphor burns, etc.). Not sure if they're worth putting on
Ebay though.....
 
On Mon, 08 Dec 2003 00:30:58 GMT, "Chris F." <zappyman@hotmail.com>
wrote:

I discovered that the focus/rectifier section of the flyback was smoking
hot. It was now obvious that the HV rectifier had shorted, and was applying
raw AC to the three CRTs, thereby causing an overload.
Click to expand...
Exactly this reasons not to blow so many HOTs (they cost too) and can
stress the HV components and it is not that hard to carefully look for
a tiny pinhole in the HV cup. When there is a arcing problem, I don't
power it up at all times once arcing noise is discovered. Then
visually carefully inspect everything. If not found, I do a very
short test with lights out and watch from distrance and turn set on.
If you see a spark or hear noise clearly then you're successful.

Except I used HV probe with ground clipped to metal structure of
projector as a radar detector waving the tip over every part of HV
stuff till i get a some reading.
This what I did on one RCA projector. The RCA uses metal collar
around the bell of CRT to clamp tube to coolant cavity via this collar
and bolts & spring assembly. The HV suction cups are only 1/4" apart
from this edge of steel collar. I think what saved this set from too
much damange was this second silicone cover, looks like a flattened
grey hat over each HV suction cups.

Still have the old suction cup? You will see a tiny discolored spot
or a tracking, in middle of that spot is a tiny pinhole made visible
by pulling and bending that suction cup. Leaking from HV lead is
possible.

BTW, blowing a HOT at one spark from HV seems lousy. I liked sets
that can survive multiple arc overs showing they had some thought into
that design.

Cheers,

Wizard
 
"Chris F." <zappyman@hotmail.com> wrote in message
news:6DPAb.7368$IF6.332357@ursa-nb00s0.nbnet.nb.ca...
After several more days of fruitless labor, including successful
cleaning
and coolant refill on all 3 CRTs, I am finally at a dead end on this
thing.
If you haven't seen my last couple of posts, this is a Sony model
KPR-36XBR
projection set. It originally had severe high voltage arcing around the
anode caps. I blew around 7-10 HOTs before finally stopping the arcing -
by
replacing the CRACKED anode connectors and completely sealing the new ones
in with silicone. But now the HOT would overheat if the HV was connected
to
anything. I disconnected the HV and it only measured 10kV. After some
time,
I discovered that the focus/rectifier section of the flyback was smoking
hot. It was now obvious that the HV rectifier had shorted, and was
applying
raw AC to the three CRTs, thereby causing an overload.
I could have screamed!! I guess all the arcing did the flyback in.
There's
only one thing that will save this set from the trash now - if some
generous
soul on this NG has a good used one that they'd give or sell me for a
reasonable price. Part #, by the way, is 1-439-366-12. Discontinued by
Sony.
Otherwise, the next guy to get his hands on this set will be the trash
collector. I may save the CRTs as they are now in fairly decent shape
(good
emissions, no phosphor burns, etc.). Not sure if they're worth putting on
Ebay though.....
Click to expand...
I've got another idea, could you replace the HV diode? If the internal one
is shorted you could leave it in place, and tag on several microwave oven
diodes in series externally, you may also have to put diodes on the focus
wire, dunno, maybe worth trying.
 
I thought about that. However, the focus/rectifier area of the flyback still
gets really hot, even if the focus and HV leads are not connected to
anything. It might be possible to cut/grind away the epoxy to remove the
shorted components, but I'd need a service manual to figure out just what to
replace them with. Often these flybacks have tricky voltage dividers which
are very hard to fabricate...
Seems a shame to give up on the set, this close to having it working.

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:zHWAb.56486$_M.269291@attbi_s54...
"Chris F." <zappyman@hotmail.com> wrote in message
news:6DPAb.7368$IF6.332357@ursa-nb00s0.nbnet.nb.ca...
After several more days of fruitless labor, including successful
cleaning
and coolant refill on all 3 CRTs, I am finally at a dead end on this
thing.
If you haven't seen my last couple of posts, this is a Sony model
KPR-36XBR
projection set. It originally had severe high voltage arcing around the
anode caps. I blew around 7-10 HOTs before finally stopping the arcing -
by
replacing the CRACKED anode connectors and completely sealing the new
ones
in with silicone. But now the HOT would overheat if the HV was connected
to
anything. I disconnected the HV and it only measured 10kV. After some
time,
I discovered that the focus/rectifier section of the flyback was smoking
hot. It was now obvious that the HV rectifier had shorted, and was
applying
raw AC to the three CRTs, thereby causing an overload.
I could have screamed!! I guess all the arcing did the flyback in.
There's
only one thing that will save this set from the trash now - if some
generous
soul on this NG has a good used one that they'd give or sell me for a
reasonable price. Part #, by the way, is 1-439-366-12. Discontinued by
Sony.
Otherwise, the next guy to get his hands on this set will be the trash
collector. I may save the CRTs as they are now in fairly decent shape
(good
emissions, no phosphor burns, etc.). Not sure if they're worth putting
on
Ebay though.....



I've got another idea, could you replace the HV diode? If the internal one
is shorted you could leave it in place, and tag on several microwave oven
diodes in series externally, you may also have to put diodes on the focus
wire, dunno, maybe worth trying.
Click to expand...
 
I managed to chip/grind away most of the focus divider area with a Dremel,
and I located the other end of the HV secondary winding. However, I now need
to know just what components to sub for the focus. This is where a service
manual comes in. I don't suppose anyone could scan me the flyback area of
the schematic?

"Chris F." <zappyman@hotmail.com> wrote in message
news:Y41Bb.7666$IF6.352095@ursa-nb00s0.nbnet.nb.ca...
I thought about that. However, the focus/rectifier area of the flyback
still
gets really hot, even if the focus and HV leads are not connected to
anything. It might be possible to cut/grind away the epoxy to remove the
shorted components, but I'd need a service manual to figure out just what
to
replace them with. Often these flybacks have tricky voltage dividers which
are very hard to fabricate...
Seems a shame to give up on the set, this close to having it working.

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:zHWAb.56486$_M.269291@attbi_s54...

"Chris F." <zappyman@hotmail.com> wrote in message
news:6DPAb.7368$IF6.332357@ursa-nb00s0.nbnet.nb.ca...
After several more days of fruitless labor, including successful
cleaning
and coolant refill on all 3 CRTs, I am finally at a dead end on this
thing.
If you haven't seen my last couple of posts, this is a Sony model
KPR-36XBR
projection set. It originally had severe high voltage arcing around
the
anode caps. I blew around 7-10 HOTs before finally stopping the
arcing -
by
replacing the CRACKED anode connectors and completely sealing the new
ones
in with silicone. But now the HOT would overheat if the HV was
connected
to
anything. I disconnected the HV and it only measured 10kV. After some
time,
I discovered that the focus/rectifier section of the flyback was
smoking
hot. It was now obvious that the HV rectifier had shorted, and was
applying
raw AC to the three CRTs, thereby causing an overload.
I could have screamed!! I guess all the arcing did the flyback in.
There's
only one thing that will save this set from the trash now - if some
generous
soul on this NG has a good used one that they'd give or sell me for a
reasonable price. Part #, by the way, is 1-439-366-12. Discontinued by
Sony.
Otherwise, the next guy to get his hands on this set will be the
trash
collector. I may save the CRTs as they are now in fairly decent shape
(good
emissions, no phosphor burns, etc.). Not sure if they're worth putting
on
Ebay though.....



I've got another idea, could you replace the HV diode? If the internal
one
is shorted you could leave it in place, and tag on several microwave
oven
diodes in series externally, you may also have to put diodes on the
focus
wire, dunno, maybe worth trying.
Click to expand...
 
Hi Chris,

I think I can help you with that schematic. I'll send it along in the next day
or two.

Regards,
David Farber

Subject: Re: Last-Ditch effort on Sony PTV
From: "Chris F." zappyman@hotmail.com
Date: 12/08/2003 11:35 AM Pacific Standard Time
Message-id: <Fn4Bb.7802$IF6.356011@ursa-nb00s0.nbnet.nb.ca

I managed to chip/grind away most of the focus divider area with a Dremel,
and I located the other end of the HV secondary winding. However, I now need
to know just what components to sub for the focus. This is where a service
manual comes in. I don't suppose anyone could scan me the flyback area of
the schematic?

"Chris F." <zappyman@hotmail.com> wrote in message
news:Y41Bb.7666$IF6.352095@ursa-nb00s0.nbnet.nb.ca...
I thought about that. However, the focus/rectifier area of the flyback
still
gets really hot, even if the focus and HV leads are not connected to
anything. It might be possible to cut/grind away the epoxy to remove the
shorted components, but I'd need a service manual to figure out just what
to
replace them with. Often these flybacks have tricky voltage dividers which
are very hard to fabricate...
Seems a shame to give up on the set, this close to having it working.

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:zHWAb.56486$_M.269291@attbi_s54...

"Chris F." <zappyman@hotmail.com> wrote in message
news:6DPAb.7368$IF6.332357@ursa-nb00s0.nbnet.nb.ca...
After several more days of fruitless labor, including successful
cleaning
and coolant refill on all 3 CRTs, I am finally at a dead end on this
thing.
If you haven't seen my last couple of posts, this is a Sony model
KPR-36XBR
projection set. It originally had severe high voltage arcing around
the
anode caps. I blew around 7-10 HOTs before finally stopping the
arcing -
by
replacing the CRACKED anode connectors and completely sealing the new
ones
in with silicone. But now the HOT would overheat if the HV was
connected
to
anything. I disconnected the HV and it only measured 10kV. After some
time,
I discovered that the focus/rectifier section of the flyback was
smoking
hot. It was now obvious that the HV rectifier had shorted, and was
applying
raw AC to the three CRTs, thereby causing an overload.
I could have screamed!! I guess all the arcing did the flyback in.
There's
only one thing that will save this set from the trash now - if some
generous
soul on this NG has a good used one that they'd give or sell me for a
reasonable price. Part #, by the way, is 1-439-366-12. Discontinued by
Sony.
Otherwise, the next guy to get his hands on this set will be the
trash
collector. I may save the CRTs as they are now in fairly decent shape
(good
emissions, no phosphor burns, etc.). Not sure if they're worth putting
on
Ebay though.....



I've got another idea, could you replace the HV diode? If the internal
one
is shorted you could leave it in place, and tag on several microwave
oven
diodes in series externally, you may also have to put diodes on the
focus
wire, dunno, maybe worth trying.
Click to expand...
 
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