viewsonic vx922 revisited

[blutch]

when i disconnect the power board completly, minimal voltage.
as far as caps i replaced....NRWA series M for the two 470uf 25v (mine are 35v), and another no name with just an M on it for the one 330uf 35v.
the 2 big caps on the logic board g-luxon 411b(M) 330uf 16v, and one sheng 100uf 25v on the logic board. i have panasonic fm caps coming to do a total reswap.
if i put it all together again and plug it in with the power switch off i get a constant 12.42 v on the 12v connector between boards.
i recapped an identical monitor 2 weeks ago, and have been useing it since,. this one is just driving me nuts .......

[Scenic]

Re: viewsonic vx922 revisited

so you're getting a voltage with the power board unplugged (12V), but as soon as you plug the LCD controller board in there's nothing?
or does it simply not power up despite the voltage being there?

i'm confused..

[retiredcaps]

Re: viewsonic vx922 revisited

i'm confused..

That is because this is the 3rd thread that the OP started with the same problem. I already told the OP not cross post yesterday because it is confusing to follow, but the OP is apparently ignoring me.

So I give up trying to help on this one.

[Scenic]

Re: viewsonic vx922 revisited

oh well.. only thing i can say for sure is that if the PSU is dead, you can simply remove one of the secondary side caps (they're all in parallel and on 12V) and solder wires in for an external 12V PSU with at least 3A.

i've "fixed" quite a few LCDs with this PSU/inverter board like this.
all i did was remove the AC socket, put a small metal plate where the socket used to be (drill 2 holes and mount it with screws and nuts) and mounted a standard DC jack (like the ones on laptops) on that metal plate.

12V power bricks are available like sand on the beach and don't cost much. plus you'll remove the biggest heat source from the monitor housing.

if you don't wanna spend a couple bucks on a power brick, you could just tap into your computer PSU's 12V.. with the added bonus that you'll never have to worry about turning your monitor on and off again

[blutch]

Re: viewsonic vx922 revisited

so you're getting a voltage with the power board unplugged (12V), but as soon as you plug the LCD controller board in there's nothing?
or does it simply not power up despite the voltage being there?

i'm confused..

no only minimal with the board out of the monitor. but if i put it back in and hook everything up.....plugged in, with the power switch off, i get a constant 12.42v. as soon as i turn it on, with the power switch. the voltage starts to fluctuate from 12.42v down to 4v. in sequence with the green led on the switch. also there is a faint clicking noise in time with the others.
thanks for any help on this, i'm new at this forum thing.

[Scenic]

Re: viewsonic vx922 revisited

hm. this kinda sounds like a short on the inverter/backlight side of things.

as an example/explanation:
if the transistors for the backlight are shorted, the powersupply is working fine as long as the monitor is turned off (12V there, monitor off/standby), but when you turn it on, the powersupply runs into a short and goes into protect mode (clicking/chirping noise.. that's the powersupply trying to restart)