Viewsonic VA2216w

[Joun]

Hello every one and happy new year..
I have this Viewsonic VA2216w monitor that acts a little strange ( to me at least )
It comes alive just fine but as you can see at pictures the image is distorted,with very high contrast,strange colors and the most starange at all,the new image takes a few seconds to appear..
I mean I open a new window and it takes at least 10 seconds to slowly appear on screen(in my other monitor comes up instantly)
I understand it's not a supply problem, it is a video board problem, right?
I measure all voltages just to be sure and they appear normal.The only one that appeared a little strange is the On/Off which is 3.0 Volts..Is that normal?
Do you think I can check anything else?

Thank you.

[Joun]

Re: Viewsonic VA2216w

I just saw a few posts before mine, a member had exactly the same problem with Samsung 2233SN monitor.
I read the answers and took a picture of t-con board..

[jetadm123]

Re: Viewsonic VA2216w

I would start by re-seating the large flat ribbon cable on the signal card in your last photo.

Also, try measuring the voltage on each leg of U1 (also in your last photo).

[Joun]

Re: Viewsonic VA2216w

I have try to re-seat ribbon cable allready ,no luck..I have also measure it's continuity it's OK.
Where is this U1? You mean IC503?

Thank you.

[jetadm123]

Re: Viewsonic VA2216w

On your last photo, it's the large 3-legged device to the right of the large brown cap, C3.

[Joun]

Re: Viewsonic VA2216w

Sorry, I can't see it.
Is it to the right or left of L501?

[retiredcaps]

Re: Viewsonic VA2216w

See pic.

[Joun]

Re: Viewsonic VA2216w

Oh I was talking about the picture of the LCD board,here it is:

[jetadm123]

Re: Viewsonic VA2216w

Oh I was talking about the picture of the LCD board,here it is:

Voltages look good. At this time, I don't have any additional ideas.

[Joun]

Re: Viewsonic VA2216w

OK, thank you for your time.As I don't have any idea too, I guess I will put everything in it's place and keep it for spares..

[PlainBill]

Re: Viewsonic VA2216w

The symptoms indicate a problem with the tcon. One of the critical voltage points (VDDA) is shown in the picture. Perhaps you should take pictures of the parts you haven't shown.

PlainBill

[Joun]

Re: Viewsonic VA2216w

Here they are:

[PlainBill]

Re: Viewsonic VA2216w

Here they are:

Good pictures. Voltage points (VDDA, VDDG, VEEG) are listed, but I don't see the specific test points. This is definitely one for momaka.

PlainBill

[momaka]

Re: Viewsonic VA2216w

I'm not entirely convinced this is a t-con problem, but let's check it anyways since the t-con step-up rails can cause similar issues (usually white screen or fade-to-white screen).

AVDD is the primary step-up rail. Typically 9 to 15V, depending on the monitor. AVDD is connected to the cathode side of D501 (D501 is right next to that round inductor L501). Cathode side of D501 is the one marked with a white stripe on diode D501.
There are 2 tests to perform for this rail:
1. Measure the resistance between AVDD rail and ground (with the monitor turned off, of course). Use lowest resistance scale if your multimeter is manual.
2. Measure the voltage between AVDD rail and ground.
Write down the results for the tests above and post them here.

VDDG and VEEG are the secondary step-up rails. Typically 15 to 25V for VDDG and -5 to -10V for VEEG. Unfortunately this t-con does not use a smart IC, so finding these is a bit more difficult. So there are 3 things to test here:
1. My guess is that Q507 and Q508 are used as regulators for these rails, so measure the voltage with respect to ground on all pins of Q507 and Q508 and post the results here. Q507 and Q508 are the black 4-pin rectangular devices seen in this picture
2. I know for sure that diodes D502, D503, and D504 (the black rectangular 3-pin components) are the rectifiers for VDDG and VEEG, but not sure which is for which. Therefore, measure the voltages on all pins of D502, D503, and D504 and post the results here. Internally, these diodes usually look like this (helpful when you list the voltages at the pins).
3. One of the small (tan-colored) ceramic caps around the diodes above may be shorted. Measure resistance across each of the following capacitors (using the lowest scale on your multimeter):
C511, C512, C526, C525, C510, C513
Only post the results for those caps that show less than 200 Ohms resistance.

Right above the LVDS connector on the t-con is IC502. Given the proximity to the big chip, this is probably a 1.8V or 3.3V regulator. Check the voltage at the various pins of this regulator with respect to ground. One of them should be either 1.8V or 3.3V.

[Joun]

Re: Viewsonic VA2216w

Wow, lots of information here..Thank you for answering..
I will get back ASAP.

[Joun]

Re: Viewsonic VA2216w

Here are the voltages. Hope you can figure out what's wrong.
Didn't find any short circuited caps..

[momaka]

Re: Viewsonic VA2216w

Well, all of the voltages seem fine. Do any of the components seem to run hot when the monitor is on? - more particularly, does D501 on the t-con get hot?

VDDG and VEEG are the 2 rails responsible for turning the transistors in the LCD TFT ON and OFF (ON for full black screen and OFF for full white screen). Perhaps the negative rails needs to be lower (although I'm not quite sure on that). There's a variable resistor, VR501 close to Q507 and Q508. I wonder if this controls the voltage for VDDG and VEEG and whether it can be adjusted to fix the problem....
But that still doesn't explain the 10 second delay your getting. Therefore the problem might not necessarily be the t-con board.

The only other thing I can think of is if those CapXon caps on the video/logic board next to the regulator (seen in this picture) are bad.

If you feel comfortable with soldering caps, try replacing those small CapXon caps I mentioned above and see if that fixes the problem. Otherwise, you could also try playing with VR501. Just to let you know: I'm not sure what VR501 does and whether adjusting it can damage the t-con board, so proceed with caution if you do decide to adjust it.

[Joun]

Re: Viewsonic VA2216w

Hello momaka and thank you for your answer..
I forgot to tell you that two days ago while I was waiting for your answer, I desoldered with hot air D501 and measure it with my DMM.
It read 0.150V.. Isn't it very low? It should be around 0.6-07 or not?
I have also desolder and measure the bigger Capcon capacitor with my ESR meter and the smaller ones(without desoldering),they all seem to be fine..
I will try messing with the little trimmer(not expecting much to happen) ..

[pedro]

Re: Viewsonic VA2216w

I desoldered with hot air D501 and measure it with my DMM. It read 0.150V.. Isn't it very low? It should be around 0.6-07 or not?

Not if it is a Schottky diode. Google the part number and see what type of diode it is.

[Joun]

Re: Viewsonic VA2216w

I'll try to read part number..But since it's not open circuit or short circuit I guess it's OK..