Viewsonic VP201B - Bad Caps or other issue? Pics Included.

[.bg.]

I have perused these forums a few times, but this is the first time I'm taking to the plunge to attempt to repair one of my dead monitors.

I have several Viewsonic VP201B LCD monitors. A couple years ago I had one of them go out. I replaced it with a new one. Sometime last year I had a second one die which I also replaced. I've finally pulled them out of the closet and want to see if I can get them working instead of hauling them out to the trash.

This thread deals with the first of the two monitors. I can't quite recall how this monitor began to die, but I believe it seemed heat related. After warming up it there would be vertical strips that would begin to get "fuzzy" and eventually just blank out. If I remember correctly, if I smacked the monitor pretty hard on the face when it started doing this it would often fix the problem for a few more minutes before it would return.

Eventually, it would have the white bars immediately when turned on and they would remain on all of the time. That's when I replaced it.

I picked up a VP201B capacitor kit from ebay for it, but have yet to install any of them. I have read all of the VP201B threads I could find and realized that it didn't seem like any of the ones that were on here died in this way. (Seems that the usual bad capacitor symptom on these monitors is them simply not turning on?)

I have pulled apart the monitor and removed the two accessible ribbon cables you can see in the pictures and then reset them to see if this helped. No luck.

Before I go through the trouble of attempting to replace the capacitors, do you guys think this is actually a capacitor related issue?

Any guidance is greatly appreciated!

[PlainBill]

Re: Viewsonic VP201B - Bad Caps or other issue? Pics Included.

1. Don't post pictures inline. It seriously inconveniences those who have a slow connection, and annoys the rest of us.

2. This is a bad connection between the flex conductive strips and the glass LCD panel. It's unrepairable.

3. If you go around hitting monitors on the face, sooner or later they will hit back.

PlainBill

[jetadm123]

Re: Viewsonic VP201B - Bad Caps or other issue? Pics Included.

Since it sounds like the monitor is not repairable, maybe you can use the power supply and/or the logic board from it to get your second monitor up and running. If you get the second monitor up and running, then replace the caps on the power supply before you put it back together.

[.bg.]

Re: Viewsonic VP201B - Bad Caps or other issue? Pics Included.

1. Don't post pictures inline. It seriously inconveniences those who have a slow connection, and annoys the rest of us.

2. This is a bad connection between the flex conductive strips and the glass LCD panel. It's unrepairable.

3. If you go around hitting monitors on the face, sooner or later they will hit back.

PlainBill

Sorry, I attempted to edit the post after I submitted, however, the forum doesn't allow me to do such.

My second monitor seems to have the same problem just in an earlier stage. After warming up it will start to flicker and eventually blank out. Again, hitting on the top or face will bring it back for a few minutes.

It's unfortunate this is unrepairable. Are the monitors generally worth anything to anybody or is it best to just trash them? (ebay doesn't seem to have any completed listings for damaged units)

[Th3_uN1Qu3]

Re: Viewsonic VP201B - Bad Caps or other issue? Pics Included.

You can sell the boards inside them and the CCFL lamps inside the panels. The panels themselves are unfixable, sorry.

[jsog]

Re: Viewsonic VP201B - Bad Caps or other issue? Pics Included.

My second monitor seems to have the same problem just in an earlier stage. After warming up it will start to flicker and eventually blank out. Again, hitting on the top or face will bring it back for a few minutes.

That sounds like a different problem. Could be cracked solder joints on the transformers.

[penderjv]

Re: Viewsonic VP201B - Bad Caps or other issue? Pics Included.

Thanks to everybody in this thread.
My VP201b had the exact same problem as .bg.'s.
Even the same area on the screen was affected, as provided by .bg.'s pictures.
Based on PlainBill's advice:

"This is a bad connection between the flex conductive strips and the glass LCD panel. It's unrepairable."

I knew where to look for the problem.
Since the monitor was useless as it was, I figured I couldn't do anymore damage to it than it already had.

I disassembled the monitor down to the LCD assembly, a unit made by LG Philips.
I carefully removed a metal cover at the top of the assembly, which revealed a circuit board which runs across the top of the display. This board receives the FlatLink LVDS data signals from the ViewSonic main control board, which then provides the X and Y driver signals to the TFT display itself. These X / Y driver signals are provided to the TFT display by 10 high-density flex ribbon cables, which are bonded directly to the circuit board.

A little web surfing, I found that these connectors are bonded to the circuit board using a special elastomer having embedded conductive beads. Special tools use heat and pressure to cause the elastomer to fuse the board and flex cables together, while pressure applied over the fingers on the board and strip squeeze the conductive beads together to establish a conductive path between the board and flex cable.

OK, it does not sound too promising at this point. I was, however, able to determine which flex cable was the culprit, and was lucky enough for it to be between the board and flex, rather than between the flex and glass LCD. In fact, I never even disassembled the assembly any farther than remove the metal cover to reveal the circuit board.

Applying pressure to the offending flex cable bond to the circuit board immediately cleared up the problem.

These flex strips are bonded to the circuit board at the absolute, very, very top of the display panel. In fact, they are only about 1/4 inch down from the top edge of the plastic case. I am of the opinion that the internal heat from the electronics and fluorescent lamps has a negative impact on these bonds over time, which is probably explains why the problem develops over time.

I cut out a large hole in the back plastic cover of this display. The hole runs across the entire top edge of the display. This hole serves two purposes - - it allows for better ventilation than the existing tiny slits provided by ViewSonic. It also allows access to the flex ribbon cable bonds without any dis-assembly of the display, in case the problem returns in the future. So far, it has been solid as a rock.