AOC 7vlr excessive HV

[Mike]

I have this monitor, and when you power it on, it will degauss.

The HV will kick up, and a loud snap is heard and it is shut down. the HV
sounded kinda strong in the first place.

after close examination, it was arching in the tube socked. I pulled the
tube socket and tried it again. and i could see the internal spark between
where the 2 focus leads go into the socket. I pull one of them and tried
again, this time I seen an arc with the same magnitude somewhere else in the
tube socket.

Sounds as if the HV is going exessive and shutting down.

In other words, im guessing the safty hold-down capacitors.

Any ideas?

 

[Sam Goldwasser]

If you are getting arcing at the spark gaps with the tube socket pulled,
it may also be a short in the flyback causing the focus voltage to be
excessive, but not necessarily the HV.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the Feedback Form at repairfaq.org. Thanks.


"Mike" <mbates14@fuse.net> writes:

I have this monitor, and when you power it on, it will degauss.

The HV will kick up, and a loud snap is heard and it is shut down. the HV
sounded kinda strong in the first place.

after close examination, it was arching in the tube socked. I pulled the
tube socket and tried it again. and i could see the internal spark between
where the 2 focus leads go into the socket. I pull one of them and tried
again, this time I seen an arc with the same magnitude somewhere else in the
tube socket.

Sounds as if the HV is going exessive and shutting down.

In other words, im guessing the safty hold-down capacitors.

Any ideas?

 

[Mike]

well, what I meant was, there isnt any arching in the spark gaps. the
arching is inside the tube socket. at first, i sen the arching between the 2
focus leads.

If i pull out BOTH leads, and leave them apart from each other, then when i
try to power it up, it will arch in the tube socket again, but this time
somewhere else between 2 or so pin connectors.



"Sam Goldwasser" <sam@saul.cis.upenn.edu> wrote in message
news:6wvfr4jy1o.fsf@saul.cis.upenn.edu...

If you are getting arcing at the spark gaps with the tube socket pulled,
it may also be a short in the flyback causing the focus voltage to be
excessive, but not necessarily the HV.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work.
To
contact me, please use the Feedback Form at repairfaq.org. Thanks.


"Mike" <mbates14@fuse.net> writes:

I have this monitor, and when you power it on, it will degauss.

The HV will kick up, and a loud snap is heard and it is shut down. the
HV
sounded kinda strong in the first place.

after close examination, it was arching in the tube socked. I pulled the
tube socket and tried it again. and i could see the internal spark
between
where the 2 focus leads go into the socket. I pull one of them and tried
again, this time I seen an arc with the same magnitude somewhere else in
the
tube socket.

Sounds as if the HV is going exessive and shutting down.

In other words, im guessing the safty hold-down capacitors.

Any ideas?

 

[techforce]

That dont make sense. With those 2 Wires out, theres really not alot of
Voltage typicly on the other pins If I recall.

The R-G-B Drives are what? Maybe 60-80 VDC max, and DC usually does not arc
very often when its that low. Is there junk on the board you can clean? Else
I would Remove and Inspect the Socket for defects.


"Mike" <mbates14@fuse.net> wrote in message
news1Wfb.56798$uJ2.52753@fe3.columbus.rr.com...

well, what I meant was, there isnt any arching in the spark gaps. the
arching is inside the tube socket. at first, i sen the arching between the
2
focus leads.

If i pull out BOTH leads, and leave them apart from each other, then when
i
try to power it up, it will arch in the tube socket again, but this time
somewhere else between 2 or so pin connectors.



"Sam Goldwasser" <sam@saul.cis.upenn.edu> wrote in message
news:6wvfr4jy1o.fsf@saul.cis.upenn.edu...
If you are getting arcing at the spark gaps with the tube socket pulled,
it may also be a short in the flyback causing the focus voltage to be
excessive, but not necessarily the HV.

--- sam | Sci.Electronics.Repair FAQ Home Page:
http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info:
http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work.
To
contact me, please use the Feedback Form at repairfaq.org. Thanks.


"Mike" <mbates14@fuse.net> writes:

I have this monitor, and when you power it on, it will degauss.

The HV will kick up, and a loud snap is heard and it is shut down. the
HV
sounded kinda strong in the first place.

after close examination, it was arching in the tube socked. I pulled
the
tube socket and tried it again. and i could see the internal spark
between
where the 2 focus leads go into the socket. I pull one of them and
tried
again, this time I seen an arc with the same magnitude somewhere else
in
the
tube socket.

Sounds as if the HV is going exessive and shutting down.

In other words, im guessing the safty hold-down capacitors.

Any ideas?

 

[Mike]

it doesnt make since. thats why im asking.




"techforce" <techforce@~nospam!juno.com> wrote in message
news:UqYfb.5624$qK1.4883623@news2.news.adelphia.net...

That dont make sense. With those 2 Wires out, theres really not alot of
Voltage typicly on the other pins If I recall.

The R-G-B Drives are what? Maybe 60-80 VDC max, and DC usually does not
arc
very often when its that low. Is there junk on the board you can clean?
Else
I would Remove and Inspect the Socket for defects.


"Mike" <mbates14@fuse.net> wrote in message
news1Wfb.56798$uJ2.52753@fe3.columbus.rr.com...
well, what I meant was, there isnt any arching in the spark gaps. the
arching is inside the tube socket. at first, i sen the arching between
the
2
focus leads.

If i pull out BOTH leads, and leave them apart from each other, then
when
i
try to power it up, it will arch in the tube socket again, but this time
somewhere else between 2 or so pin connectors.



"Sam Goldwasser" <sam@saul.cis.upenn.edu> wrote in message
news:6wvfr4jy1o.fsf@saul.cis.upenn.edu...
If you are getting arcing at the spark gaps with the tube socket
pulled,
it may also be a short in the flyback causing the focus voltage to be
excessive, but not necessarily the HV.

--- sam | Sci.Electronics.Repair FAQ Home Page:
http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info:
http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer
work.
To
contact me, please use the Feedback Form at repairfaq.org. Thanks.


"Mike" <mbates14@fuse.net> writes:

I have this monitor, and when you power it on, it will degauss.

The HV will kick up, and a loud snap is heard and it is shut down.
the
HV
sounded kinda strong in the first place.

after close examination, it was arching in the tube socked. I pulled
the
tube socket and tried it again. and i could see the internal spark
between
where the 2 focus leads go into the socket. I pull one of them and
tried
again, this time I seen an arc with the same magnitude somewhere
else
in
the
tube socket.

Sounds as if the HV is going exessive and shutting down.

In other words, im guessing the safty hold-down capacitors.

Any ideas?

 

[John Gill]

"Mike" <mbates14@fuse.net> wrote in message news:<3e0gb.22786$cK5.8932@fe1.columbus.rr.com>...

it doesnt make since. thats why im asking.

The sets that I have had that were arching in the CRT socket had problems

in the high-voltage transformer (flyback) allowing the high-voltage to
reach the focus pins. I had measured about 20KV at the focus pins (set
running) when it should have been in the range of 6 to 8 KV. Have you measured
the voltage on the focus pins ?
It is possible that the high-voltage is getting to the G1 (screen) pot
on the flyback, causing the screen voltage to be way too high. It should
be in the range of 400 to 600 volts (measured with a 100 to 1 probe). The
screen voltage is very high impedence and is usually over-loaded by the
regular meter (regular meter might read about 200-300 volts).
Hope this helps...
John

 

[Mike]

your probably right.

if it were an open hold-down cap, it would arc around the aquadag.

Where can i get the flybacks for these? im not that familar with computer
monitor flyback replacements. ive replaced dosens in TV sets.





"John Gill" <jdgill@juno.com> wrote in message
news:71016e83.0310060659.1e3ebbd6@posting.google.com...

"Mike" <mbates14@fuse.net> wrote in message
news:<3e0gb.22786$cK5.8932@fe1.columbus.rr.com>...
it doesnt make since. thats why im asking.

The sets that I have had that were arching in the CRT socket had problems
in the high-voltage transformer (flyback) allowing the high-voltage to
reach the focus pins. I had measured about 20KV at the focus pins (set
running) when it should have been in the range of 6 to 8 KV. Have you
measured
the voltage on the focus pins ?
It is possible that the high-voltage is getting to the G1 (screen) pot
on the flyback, causing the screen voltage to be way too high. It should
be in the range of 400 to 600 volts (measured with a 100 to 1 probe). The
screen voltage is very high impedence and is usually over-loaded by the
regular meter (regular meter might read about 200-300 volts).
Hope this helps...
John

 

[Mike]

yeap, your right. bad fly.


i removed both focus wires, AND ISOLATED THEM APART, alot farther from each
other.

no more cracking.
but the high voltege comes up, and its on for a second, it makes a hiss and
shuts down, and tries again over and over.

the way it sounds, it sounds like a techno beat.

im thinking the uPC is seeing the shorted windings between the HV and focus
windings, and shutting it down.

Anybody know where I can get the flybacks for these?




"Mike" <mbates14@fuse.net> wrote in message
news:xXJfb.56487$uJ2.32740@fe3.columbus.rr.com...

I have this monitor, and when you power it on, it will degauss.

The HV will kick up, and a loud snap is heard and it is shut down. the HV
sounded kinda strong in the first place.

after close examination, it was arching in the tube socked. I pulled the
tube socket and tried it again. and i could see the internal spark between
where the 2 focus leads go into the socket. I pull one of them and tried
again, this time I seen an arc with the same magnitude somewhere else in
the
tube socket.

Sounds as if the HV is going exessive and shutting down.

In other words, im guessing the safty hold-down capacitors.

Any ideas?