Viewsonic vx910

[ajsemtb]

Re: Viewsonic vx910

Is anyone still on this post? I'm working on another thread with VX910 name as well, but I had a question for Maugli, which ceramic caps near the transformers are youtalking about? the 2 blue ones? There is a red poly cap right next to the Transformer too... BTW, same blinky green light of death on mine, replaced elecrolyte caps, and transistors, but when tried it out, popped the transistors on bottom. Will replace those again, but want to fix problem before I turn it on again... :/

[ppm007]

Re: Viewsonic vx910

Also check die Schottky Diode near those 2SC4672: D9 and D10

At a german board a guy with same problem wrote:
You can check both Inverters by R18,R22 and R20,23: if ok everyone should have 750 Ohm. If one Inverter is broken, the resistance should be lower

[PlainBill]

Re: Viewsonic vx910

For those who are trying to repair this monitor, a service manual (actually for the Beleina 101910) can be found here. Thanks, pmm007 for the link.

The transistors mentioned are available as DK Qx from Fran's LCD Monitor Repair on eBay for $7.50 a pair plus shipping. OR they are available as 2SC4672 Q from Digikey (part number 2SC4672T100QCT-ND) for $.72 each.

To others who are going through the same hell I did, the transistors are labeled DK at one end and QH, QQ, QF, QD, etc at the other. The Q indicates gain, the second letter is a production code.

PlainBill

[Maluko75]

Re: Viewsonic vx910

The underside of the board coming soon.....works got me tooo busy.

[Krankshaft]

Re: Viewsonic vx910

Set DMM to diode check. Measure from base to collector switch orientation of probes you should only get a reading in one direction. Do the same for base to emitter any short indicates a bad transistor.

Based on the pics of 2 inverter transformers (near the blue HV caps) you will have 2 transistors per transformer. Since I can't find them on the top side of the board they are surface mounted on the underside of the board usually as close to the transformers as possible.

[Maluko75]

Re: Viewsonic vx910

So how do i check the transitors to see if their faulty,i've replaced all those caps on top...

[PlainBill]

Re: Viewsonic vx910

So on the under side right/ The tiny little transitors?

Post a good picture of the underside, especially of the transistors.

PlainBill

[Maugli]

Re: Viewsonic vx910

Maluko75, I do not have the board in front of me anymore.
The transistors on the bottom and surface mounted. they will have lettering of DK QB or something like that. Digi-key has them they whole repair should cost you under 10 dollars with parts to spare.. and take less then 20 min if you can unsolder the transistors without braking the traces

[PlainBill]

Re: Viewsonic vx910

So on the under side right/ The tiny little transitors?

Yep. Maybe you should ask Maugli for the exact details.

PlainBill

[Maluko75]

Re: Viewsonic vx910

So on the under side right/ The tiny little transitors?

[PlainBill]

Re: Viewsonic vx910

Hey Bill i'll go ahead and order the correct caps FC not EB,Maybe thats my problem(Eager to see things work without proper info) you know...

I would also suggest checking out the transistors as mentioned by Maugli. The current symptoms point to a problem in the inverter or CCFLs. It's pretty well accepted that failed caps in the power supply can overstress the transistors in the inverter.

PlainBill

[Maluko75]

Re: Viewsonic vx910

Hey Bill i'll go ahead and order the correct caps FC not EB,Maybe thats my problem(Eager to see things work without proper info) you know...

[Toasty]

Re: Viewsonic vx910

See thread: https://www.badcaps.net/forum/showthread.php?t=7875

[Maluko75]

Re: Viewsonic vx910

I had ordered both series E was longer lasting then the F series...

[Maluko75]

Re: Viewsonic vx910

Whats the difference in e and f?

[PlainBill]

Re: Viewsonic vx910

Ok it flashes and shows image then disappears,bill you said c21 even if it's not bulged? Also The caps are the panasonic E series..
Hey Mau-- the transitors on the bottom side #?

Panasonic E series???? Hoo, boy. Should be FC series. And yes, it is possible the transistors in the inverter are causing the problem.

PlainBill

[Maluko75]

Re: Viewsonic vx910

Ok it flashes and shows image then disappears,bill you said c21 even if it's not bulged? Also The caps are the panasonic E series..
Hey Mau-- the transitors on the bottom side #?

[Maugli]

Re: Viewsonic vx910

When i fix the VX910 and vx924 monitors with the same problem i replace 4 electrolytic caps and two ceramic by the transformers. I also replace 4 transistors on the bottom side.. This cures the problem 100%

[PlainBill]

Re: Viewsonic vx910

:update: I hooked up the vid cable and it'll flash the image but won't stay on constant....??

You are going to have to be more precise with your description of the problem.

OK, you replaced 3 caps. Did you replace with the same capacity and voltage? What brand and series did you use?

What do you mean by "but won't stay on constant"? Does the backlight turn on, then go off and stay off until you cycle the Power button on the monitor? Or do you mean the Power button flashes on and off, and the appears and disappears?

As a first step, replace C21

PlainBill

[Maluko75]

Re: Viewsonic vx910

:update: I hooked up the vid cable and it'll flash the image but won't stay on constant....??