ViewSonic G810-2M

[Brett]

My G810-2M was working ok then one day it lost high voltage, the
deguass, power LED-green, fuction on power up then the relay kicks out
and LED turns yellow. I can not find any shorted transistors or power
MOSFETS even changed the HV regulator Mosfet K2761 for kicks, no help.
Standby voltage 10+,4.95+ stays up, the 200+vdc regulated hits about
+180 then falls as do all the others, smacking profusely helps not,
freeze spray opto couplers and HV components same results.

There is absolutely no HV at first anode and no shorted parts or caps
I can locate, even change 22uf start up cap in switcher regulator, so
it appeared to be just for kicks. I have only seen an open flyback
transformer once in 25 years and that was on a Channel Master TV, my
dad resoldered the copper wire burned in mid air and fixed it, the
days of wax coated HV-Xformers. My father has since past on but this I
shall never forget and now it is a legacy.

Do these symptoms sound familure to any of you out there or am I over
looking something, any input is welcome if it will save me $78.00+ on
a flyback as have been unemployed since june.

Happy holidays to all !!

Brett

 

[David]

Fixing the G810 always start by replacing the flyback. It is the number one
failure item in that model as they get just over 3 years old. MCM has a few
in stock at $78 or so each. Just had to order another one today, that is
three in less than 5 months for that model.

As long as the HOT did not fry and you do not find any smoked surface mount
or other components around the flyback, the flyback and possibly mosfet
regulator (and small resistor with mosfet) are 99% all you will need.

Hospital has 9 of that model in use. 3 flybacks failed in last 5 months, 2
failed earlier this year, two failed under warranty and the monitors were
replaced by Viewsonic.

David

Brett <brett.price@glipit.com> wrote in message
news:66901ada.0312171959.491db1c5@posting.google.com...

My G810-2M was working ok then one day it lost high voltage, the
deguass, power LED-green, fuction on power up then the relay kicks out
and LED turns yellow. I can not find any shorted transistors or power
MOSFETS even changed the HV regulator Mosfet K2761 for kicks, no help.
Standby voltage 10+,4.95+ stays up, the 200+vdc regulated hits about
+180 then falls as do all the others, smacking profusely helps not,
freeze spray opto couplers and HV components same results.

There is absolutely no HV at first anode and no shorted parts or caps
I can locate, even change 22uf start up cap in switcher regulator, so
it appeared to be just for kicks. I have only seen an open flyback
transformer once in 25 years and that was on a Channel Master TV, my
dad resoldered the copper wire burned in mid air and fixed it, the
days of wax coated HV-Xformers. My father has since past on but this I
shall never forget and now it is a legacy.

Do these symptoms sound familure to any of you out there or am I over
looking something, any input is welcome if it will save me $78.00+ on
a flyback as have been unemployed since june.

Happy holidays to all !!

Brett

 

[David]

Forgot, big hint, Discharge the HV anode and remove the anode from the crt.
With a good meter, measure the resistance between the hv anode and the
ground where the focus/g2 divider block go. If you measure ANYTHING below
several 10's of megaohms, the flyback has failed. All but one read around
500K between HV anode and ground indicating an internal HV anode to ground
short.


David <dkuhajda@locl.net.spam> wrote in message
news:3fe151fa$1@news.greennet.net...

Fixing the G810 always start by replacing the flyback. It is the number
one
failure item in that model as they get just over 3 years old. MCM has a
few
in stock at $78 or so each. Just had to order another one today, that is
three in less than 5 months for that model.

As long as the HOT did not fry and you do not find any smoked surface
mount
or other components around the flyback, the flyback and possibly mosfet
regulator (and small resistor with mosfet) are 99% all you will need.

Hospital has 9 of that model in use. 3 flybacks failed in last 5 months,
2
failed earlier this year, two failed under warranty and the monitors were
replaced by Viewsonic.

David

Brett <brett.price@glipit.com> wrote in message
news:66901ada.0312171959.491db1c5@posting.google.com...
My G810-2M was working ok then one day it lost high voltage, the
deguass, power LED-green, fuction on power up then the relay kicks out
and LED turns yellow. I can not find any shorted transistors or power
MOSFETS even changed the HV regulator Mosfet K2761 for kicks, no help.
Standby voltage 10+,4.95+ stays up, the 200+vdc regulated hits about
+180 then falls as do all the others, smacking profusely helps not,
freeze spray opto couplers and HV components same results.

There is absolutely no HV at first anode and no shorted parts or caps
I can locate, even change 22uf start up cap in switcher regulator, so
it appeared to be just for kicks. I have only seen an open flyback
transformer once in 25 years and that was on a Channel Master TV, my
dad resoldered the copper wire burned in mid air and fixed it, the
days of wax coated HV-Xformers. My father has since past on but this I
shall never forget and now it is a legacy.

Do these symptoms sound familure to any of you out there or am I over
looking something, any input is welcome if it will save me $78.00+ on
a flyback as have been unemployed since june.

Happy holidays to all !!

Brett

 

[Brett]

"David" <dkuhajda@locl.net.spam> wrote in message news:<3fe151fa$1@news.greennet.net>...

Fixing the G810 always start by replacing the flyback. It is the number one
failure item in that model as they get just over 3 years old. MCM has a few
in stock at $78 or so each. Just had to order another one today, that is
three in less than 5 months for that model.

As long as the HOT did not fry and you do not find any smoked surface mount
or other components around the flyback, the flyback and possibly mosfet
regulator (and small resistor with mosfet) are 99% all you will need.

Hospital has 9 of that model in use. 3 flybacks failed in last 5 months, 2
failed earlier this year, two failed under warranty and the monitors were
replaced by Viewsonic.

David

Brett <brett.price@glipit.com> wrote in message
news:66901ada.0312171959.491db1c5@posting.google.com...
My G810-2M was working ok then one day it lost high voltage, the
deguass, power LED-green, fuction on power up then the relay kicks out
and LED turns yellow. I can not find any shorted transistors or power
MOSFETS even changed the HV regulator Mosfet K2761 for kicks, no help.
Standby voltage 10+,4.95+ stays up, the 200+vdc regulated hits about
+180 then falls as do all the others, smacking profusely helps not,
freeze spray opto couplers and HV components same results.

There is absolutely no HV at first anode and no shorted parts or caps
I can locate, even change 22uf start up cap in switcher regulator, so
it appeared to be just for kicks. I have only seen an open flyback
transformer once in 25 years and that was on a Channel Master TV, my
dad resoldered the copper wire burned in mid air and fixed it, the
days of wax coated HV-Xformers. My father has since past on but this I
shall never forget and now it is a legacy.

Do these symptoms sound familure to any of you out there or am I over
looking something, any input is welcome if it will save me $78.00+ on
a flyback as have been unemployed since june.

Happy holidays to all !!

Brett

Thanks David,

No need to discharge first anode as no Hv period, shure feels like
a complete open FB. The Mosfet reg compaired with new one ok and no
smt's in HV area look/smell bad. If HVFB is shorted Viewsonic engineers
have outdone themselves in their HV circuit protection shut down theory.
I will check the little resistor but think I had. The horizontal/vertical
deflection circuits seem fine as do the HV transistor in that area.
I will pull FB, getting good at opening this beast about 5-min
to remove the PCB from cage using electric screw driver.
Smells a like FB, looks a like FB, must be a FB!!

Brett