Monitor problems

[Glenn]

My Benq 17 inch LCD monitor died early this week. With the price of
them, I was wondering whether to bother even seeing if I could fix
it. As it turns out, I was able to find the fault and repair it, and
in the process found I wasn't the only one who had had exactly the
same problem. Some googling for the failed transistor turned up other
with the same fault in this monitor and rebadged versions of it eg
some Dell re-branding. I didn't even need to google the monitor.

It turns out that the lamp driver circuit may not be the best designed
and the driver transistors fail. Replacement fixed it but I began to
wonder how many others out there had their Benq monitor die but didn't
bother trying a fix.

Cheers
Glenn

 

[Andy Wood]

Glenn <glenn@evans-pure.net> wrote:

My Benq 17 inch LCD monitor died early this week. With the price of
them, I was wondering whether to bother even seeing if I could fix
it. As it turns out, I was able to find the fault and repair it, and
in the process found I wasn't the only one who had had exactly the
same problem. Some googling for the failed transistor turned up other
with the same fault in this monitor and rebadged versions of it eg
some Dell re-branding. I didn't even need to google the monitor.

It turns out that the lamp driver circuit may not be the best designed
and the driver transistors fail. Replacement fixed it but I began to
wonder how many others out there had their Benq monitor die but didn't
bother trying a fix.

Cheers
Glenn

The backlight on my Benq FP737s died a while ago. I was about to chuck
it out and get a new monitor but then I found a bit of info at
www.badcaps.net . I'm guessing that is where you saw claims that the
circuit is dodgy and should be modified. I did not do that, all I did
was replace one dead 2SC5707 and one blown picofuse. I resoldered the
connections to the inverter transformers for good measure. I also had
a bit of grief with a bad connection on the ribbon cable between the
VGA board and the panel board, but I managed to sort that out and it
has been working OK for about two months now.


Andy Wood
woodag@trap.ozemail.com.au

 

[Glenn]

On Jan 11, 11:50 am, woo...@trap.ozemail.com.au (Andy Wood) wrote:

Glenn <gl...@evans-pure.net> wrote:
My Benq 17 inch LCD monitor died early this week.  With the price of
them, I was wondering whether to bother even seeing if I could fix
it.  As it turns out, I was able to find the fault and repair it, and
in the process found I wasn't the only one who had had exactly the
same problem.  Some googling for the failed transistor turned up other
with the same fault in this monitor and rebadged versions of it eg
some Dell re-branding.  I didn't even need to google the monitor.

It turns out that the lamp driver circuit may not be the best designed
and the driver transistors fail.  Replacement fixed it but I began to
wonder how many others out there had their Benq monitor die but didn't
bother trying a fix.

Cheers
Glenn

The backlight on my Benq FP737s died a while ago. I was about to chuck
it out and get a new monitor but then I found a bit of info atwww.badcaps..net. I'm guessing that is where you saw claims that the
circuit is dodgy and should be modified. I did not do that, all I did
was replace one dead 2SC5707 and one blown picofuse. I resoldered the
connections to the inverter transformers for good measure. I  also had
a bit of grief with a bad connection on the ribbon cable between the
VGA board and the panel board, but I managed to sort that out and it
has been working OK for about two months now.

Andy Wood
woo...@trap.ozemail.com.au

Mine is an FP17G. 2SC5707 died too but could not find fuse and it
certainly is working after I replaced the pair of transistors (the
other went shortly after I replace the first -- lucky I ordered a
couple). Anyway, before I replaced it, I noticed a substantial dry
joint on the capacitor between the (collectors?? I think) of the
transistor pair. Not sure if this was related to the failure.

I found a few websites referring to the problem but didn't note the
URLs.

Cheers
Glenn