Viewsonic Optiquest Q19wb

[lucky13]

Re: Viewsonic Optiquest Q19wb

BTW I found 2 resistors that were shorted. Make any sense?

What's the location? I can get you the resistance value.

[MBAJACE]

Re: Viewsonic Optiquest Q19wb

R805 resistor red yellow silver gold I think 24.7ohm??? I'm learning.
Ranges from 0.5 to 0.2ohm

F802 Mustard yellow resister? Fuse possibly, reads T 4A so I think its a 4Amp fuse..
Reads 0.5 to 0.1ohm

Everything else checks out I think.

[MBAJACE]

Re: Viewsonic Optiquest Q19wb

OK I think R805 is actually fine. My meter says its shorted, a solid connection. hmmm.

[lucky13]

Re: Viewsonic Optiquest Q19wb

R805 resistor red yellow silver gold I think 24.7ohm??? I'm learning.
Ranges from 0.5 to 0.2ohm

F802 Mustard yellow resister? Fuse possibly, reads T 4A so I think its a 4Amp fuse..
Reads 0.5 to 0.1ohm

Everything else checks out I think.

That is:
red = 2
yellow = 4
silver = multipy by 0.01
goldd = 5% tolerance

So it is 24 x 0.01 = 0.24ohms!

I can't find F802. Where is it?

[MBAJACE]

Re: Viewsonic Optiquest Q19wb

It is yellowish on the edge, left I think. So I think the fuse may be the problem. with 0.1 resistance I believe there is a 2V loss and 8V may not be enough to sustain the cfls. I went over the transformer solider and bridged the fuse. Its a slow burning 4AMP and I think it is half way. The green light is blinking so there must be some flux on the board. I'm going to bridge the fuse and see what happens. I'm going to replace caps by Saturday. Whenever they get here.
If I can power cycle on/off/on and keep the backlights on it will be a success.

[PlainBill]

Re: Viewsonic Optiquest Q19wb

It is yellowish on the edge, left I think. So I think the fuse may be the problem. with 0.1 resistance I believe there is a 2V loss and 8V may not be enough to sustain the cfls. I went over the transformer solider and bridged the fuse. Its a slow burning 4AMP and I think it is half way. The green light is blinking so there must be some flux on the board. I'm going to bridge the fuse and see what happens. I'm going to replace caps by Saturday. Whenever they get here.
If I can power cycle on/off/on and keep the backlights on it will be a success.

Anyone who cannot cope with mathematics is not fully human. At best he is a tolerable sub-human who has learned to wear shoes, bathe, and not make messes in the house.
Robert A Heinlein

The inverter draws perhaps 1 amp, 2 maximum. If the resistance of the fuse is .1 ohm (did you correct for the resistance of the leads?), the voltage drop across the fuse is .2 volts.

If you still have the Rat Shaft caps in there you are wasting your time and ours. Replace them with good Panasonic FM or FC series caps.

PlainBill

[MBAJACE]

Re: Viewsonic Optiquest Q19wb

No, I took that radio shack cap out. The 4A fuse is good then and all of the circuitry tested good. The kit I bought off of ebay this morning has all of the caps. The monitor works it just gives me 1 opportunity every 4-6 hrs and it has to stay on. I guess I will start with the caps and go from there. I really want to know how to bypass or trick the circuit with a resister on I think the 7 pin. Any experience?

[PlainBill]

Re: Viewsonic Optiquest Q19wb

No, I took that radio shack cap out. The 4A fuse is good then and all of the circuitry tested good. The kit I bought off of ebay this morning has all of the caps. The monitor works it just gives me 1 opportunity every 4-6 hrs and it has to stay on. I guess I will start with the caps and go from there. I really want to know how to bypass or trick the circuit with a resister on I think the 7 pin. Any experience?

I have seen that process, and don't recommend it under any circumstances. If it is the one I am thinking of, it is for a dying mcu. It usually has the effect of quickly killing the mcu. The problem you describe is an ALMOST classic 'two seconds to black'. The winkle in your case is it won't restart for a period of time.

PlainBill

[MBAJACE]

Re: Viewsonic Optiquest Q19wb

How much factor is the shielding tape on the back of the lcd panel? I did not measure what comes off but I'm super curious.

[lucky13]

Re: Viewsonic Optiquest Q19wb

It is yellowish on the edge, left I think. So I think the fuse may be the problem. with 0.1 resistance I believe there is a 2V loss and 8V may not be enough to sustain the cfls. I went over the transformer solider and bridged the fuse. Its a slow burning 4AMP and I think it is half way. The green light is blinking so there must be some flux on the board. I'm going to bridge the fuse and see what happens. I'm going to replace caps by Saturday. Whenever they get here.
If I can power cycle on/off/on and keep the backlights on it will be a success.

I am sorry but I look at my board again and don't find this F802. Can you post a pix of it?

[lucky13]

Re: Viewsonic Optiquest Q19wb

How much factor is the shielding tape on the back of the lcd panel? I did not measure what comes off but I'm super curious.

You mean those silver tape? They are for RFI/EMI and these tape won't stick once you pull them off. Just leave them out.

[MBAJACE]

Re: Viewsonic Optiquest Q19wb

OK, thanks on the silver tape info. The fuse was not the problem. I will be putting a new set of caps in on Saturday. Hopefully that fixes it.
Where on the board would its memory be stored?
As a last resort I think I could make some kind of reset switch that drains the power from it faster than 5 hrs.
I will post the picture up soon.

[elbtax]

Re: Viewsonic Optiquest Q19wb

I have the same psu rev: c. I see no F802 on my board.

[MBAJACE]

Re: Viewsonic Optiquest Q19wb

If you're looking at the green side w plug down it is on top left corner.

[eradz]

Re: Viewsonic Optiquest Q19wb

any update on this issue? im getting the same exact thing as above, same parts and the tests are the sme.
On the pink resistors tho, there are 3 different sizes but if you look at the 2 big pink ones, one had a red band and the other a blue. ones tests out at .05(set my meter to 20m) and the other just 0.

Transformers measure .628 and .635 for 01 - 02 and 03 - 04

[lucky13]

Re: Viewsonic Optiquest Q19wb

Lamps.....lamps.....lamps.....

Get yourself a known good lamps and swap in one set at a time.

[MBAJACE]

Re: Viewsonic Optiquest Q19wb

Lamps.....lamps.....lamps.....

Get yourself a known good lamps and swap in one set at a time.

I soldered the fuse with a copper bar a few weeks ago and no problems.

I would like to know where to get replacement lamps because thats the only option I didn't try.

[Rtech]

Re: Viewsonic Optiquest Q19wb

You mean shorted together...because resistors NEVER go short Circuit on their own ??

[MBAJACE]

Re: Viewsonic Optiquest Q19wb

You mean shorted together...because resistors NEVER go short Circuit on their own ??

The fuse was part of the problem. I don't think its totally fixed but as of now I want to find some replacement lamps

[eradz]

Re: Viewsonic Optiquest Q19wb

so it seems to be bad lamps? i took apart the screen and it seems like the lamps arent any like i normally see. Like the ones u can just side out. These seem built into the whole back clear screen once u removed the top darker peice.