How to change the LCD and touch pannel of a V synth XT

hey all thanks so much for the information !

my touch screen is no longer responsive (the display works) but the linked item is no longer available.

i'm going to try this: http://ebay.to/1LdR7Yd

Touch Screen Digitizer:
- 5.7 inches, 105 x 133mm
- 4 Wire
- resistive touch
- GPS screen replacement (?)

not sure if this is right but i'm ordering one now. any clarification would be great !

I have a GT, my screen started showing intermittent issues recently, so I bought this one just in case, but I haven't installed it yet.

The one that you linked to looks like the ribbon cable part might be too short?? I have no idea how long it needs to be though, as I haven't opened my keyboard yet.

Hello everybody!
I have an issue with touch screen of my V-Synth GT. After powering up everything works fine but after a while thouch screen just stops working or working with bugs. In Calibration screen I can see a red crossed lines in top left corner of the screen and touch screen is heating up slowly. I decided to change it with new one mentioned above in this thread. But the problem remained. When I changed touch screen I tried to plug/unplug it while V-Synth was powered up and while I moved a 4-pin cable a little in connector I saw that red lines in top corner of the screen which is exact the same behavior I described above. Is it possible that something wrong is inside a connector that causes short circuit or something? Please help!

That's the same problem that I've been getting intermittently on my GT. Sometimes when I start it up, the touch screen is super slow to respond. Every time this happens, when I go into the calibration screen (a difficult operation in itself when the screen isn't working properly), the cross is in the top-left, which means the GT is sensing a phantom finger in the top-left.

It seems to happen more often during cold weather and when I haven't used it for a while. When I'm using it every day the problem doesn't seem to happen.

I'm not sure about the "heating up slowly" part though. Maybe you mean that it seems to get better when the GT has been turned on for a while, which has been my experience.

It's interesting that you had the same problem even with the new screen when wiggling the connector.

The touch screen is resistive, so any change in resistance such as a bad connection (or humidity?) could affect the touch sensing.

I would probably try cleaning the connector with isopropyl alcohol to try to get a good electrical connection. Maybe spray or wipe some on the connector, then insert and remove it a few times.

I've bought a replacement touch panel but haven't felt the need to install it yet, as my GT has been working perfectly for the last couple of months. The touch screen problem seems to come and go.

Make sure to post again and tell us how you go. I'm especially interested because I'll probably have to replace the screen on mine eventually.

Today I've tried to resolve this issue again as my touch screen stopped to work completely. I've opened the V-Synth and tried to wiggle 4 pin cable while tapping touch screen. And half of my taps were ok. So I think the problem is in CN18 connector showed in attachment. Afther an half an hour of wiggling I had no luck to find a working position and successful taps reduced by this time.

Do I need to change this connector? Is it possible? Or maybe I should try to clean contacts inside the connector?

just fyi, The Korg M3 has similar problems on touch screen. Recently I have replaced the touch screen of my M3.

Here some information, maybe could be useful, as it is used almost identical touch screen.

http://www.karma-lab.com/forum/showthread.php?t=16671

First off, let me extend a huge thank you to this community for this fix.

I ordered the following item to replace my touch screen in my V-Synth GT.

http://www.ebay.com/itm/5-7-inch-132mm-X-105mm-Touch-Screen-Digitizer-Glass-For-LM057QC1T01-LM057QC1T08/301868563540?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D40130%26meid%3D77c5d79372dc4420b9a0ba15aa0fcc5b%26pid%3D100011%26rk%3D1%26rkt%3D12%26sd%3D320699586777

I installed it and it didn't give me any touch response whatsoever. Now, my old touch panel would work after the unit got warm, so I threw the old panel back in just to see if I had damaged something in the installation. The old, flakey unit that I was replacing worked when I put it back in.

That begs several question: do you think the replacement I received was defective, did I order the wrong thing, or is it possible that maybe I had the replacement in upside down? I tried to install it exactly the same way that the other one was - with the glued portion of the cable pointing down so that the ribbon cable would bend around and connect to the module in the exact way the original screen did.

I'm just at a loss here beyond ordering another touch panel from ebay, maybe from a different seller, and trying again.

I'd love any feedback or thoughts you all may have. Thank you so much.

To me this sounds like a mechanical problem, a connector with perhaps a bent pin or something that is not consistent when you plug or unplug it. A broken solder joint on the connector. Or maybe a broken trace on the board which causes the temperature dependence. In this case, you may now have two good displays, and of course buying a third won't solve the problem. Not sure how you go about troubleshooting this other than remove and replace the display again. And then what do you find out? Either, you can't make it fail again, or you can no longer make it work at all. Neither of these is a desirable outcome.

Thanks for your response, Rodan. I'd be inclined to agree with you except for the fact that the new display doesn't work at all, whether the unit is warm or not. There's no touch response at all from the new display. The old display works sporadically until the unit heats up, and then it's still not perfect but it is much more functional. I'll see if anyone else chimes in, but I'll definitely mention what you've said here if/when I take it in for a repair at a local Roland shop. Thanks again.

I would suggest to do a few things.

First make sure that the ribbon from the touch panel is connected to the correct side. If you look at it you will see that only 1 side have contacts, the other is covered with plastic. You want to make sure that the ribbon is installed in such a way that the contact are on the same side as before.

Resistive panel are very simple devices and the pinout should be standard but if you carefully look at it you may see if there's a difference by looking at the tracks. There's basically 2 connection for the "X" position, and 2 others for the "Y" axis. If you have an voltmeter you may also check on the ohm (resistance) scale to see if the display react when you touch it the same way as the previous one.

Also note that only 1 side of the panel itself is sensitive, if the panel is upside down it would not detect the touch.

Hope this help

LA

LA Keys wrote:

I would suggest to do a few things.

First make sure that the ribbon from the touch panel is connected to the correct side. If you look at it you will see that only 1 side have contacts, the other is covered with plastic. You want to make sure that the ribbon is installed in such a way that the contact are on the same side as before.

Resistive panel are very simple devices and the pinout should be standard but if you carefully look at it you may see if there's a difference by looking at the tracks. There's basically 2 connection for the "X" position, and 2 others for the "Y" axis. If you have an voltmeter you may also check on the ohm (resistance) scale to see if the display react when you touch it the same way as the previous one.

Also note that only 1 side of the panel itself is sensitive, if the panel is upside down it would not detect the touch.

Hope this help

LA

Thanks a lot for your reply. I double checked and the ribbon cable was inserted correctly. I flipped the touch panel over just to see if I had it upside down, but that wasn't the problem. I guess it's possible that I received a bad touch panel - I'm not sure how to go about using an ohm meter to test the resistance, though.

I think I'm going to order another touch panel and try again from a different seller. I'm sure they're all the same but I think it's worth the money to try it again before I take it into a Roland repair center, as I know that's going to be super costly.

Thanks again for your input!

Greetings all. After having ordered and installed another touch panel, I'm seeing the same results: no touch response. So, I'm going to go back to previous comments and assume now that this must be some sort of mechanical issue; a bent pin, a bad solder joint, or something along those lines. The original touch panel still works once the unit heats up, albeit with occasional buggy behavior.

My new question is this: is this thing worth spending big bucks to get it repaired? I'm considering selling it in the state that it's in, because the whole point of me fixing it in the first place was to part ways with it. It just sits around in a flight case and is never used, and (fully functional) V-Synth GTs are still selling for good money.

Could anyone help me come up with a valuation on this with a non-working touch screen? The LCD screen itself is fine, and the fix might be simple, but my patience with it is about exhausted considering I'm only fixing it to sell. Everything else on the synth is in 100% working order.

Thanks again for all of your input.

I know your patience is exhausted but I'm wondering if you should try to calibrate the new touch panel. This is because if it is way off the calibration you have for the old touch panel you may have results that suggest it is not working while it may in fact be working, but simply not calibrated.

Here is how to enter test mode on the V-Synth GT:

1. Power up the V-Synth/GT.
2. Press [SYSTEM] to enter the System mode.
3. Touch <Info>.
4. Hold down [SHIFT] and press the PATCH PALETTE buttons in this sequence: [7], [8], [7], [8].
The Test mode (1. VERSION CHECK) starts.

Quitting the Test Mode
Power down the V-Synth/GT.

Once in test mode you will use [SHIFT] + right arrow key or [SHIFT} + left arrow key to go to the next/previous tests. In your case you want to do the test #18 "Touch Panel adjust" and #19 "Touch panel test".

LA

LA Keys wrote:

I know your patience is exhausted but I'm wondering if you should try to calibrate the new touch panel. This is because if it is way off the calibration you have for the old touch panel you may have results that suggest it is not working while it may in fact be working, but simply not calibrated.

Here is how to enter test mode on the V-Synth GT:

1. Power up the V-Synth/GT.
2. Press [SYSTEM] to enter the System mode.
3. Touch <Info>.
4. Hold down [SHIFT] and press the PATCH PALETTE buttons in this sequence: [7], [8], [7], [8].
The Test mode (1. VERSION CHECK) starts.

Quitting the Test Mode
Power down the V-Synth/GT.

Once in test mode you will use [SHIFT] + right arrow key or [SHIFT} + left arrow key to go to the next/previous tests. In your case you want to do the test #18 "Touch Panel adjust" and #19 "Touch panel test".

LA

Thanks so much for your suggestion, LA. Is there any way for me to get into the "Info" section in System without having any touch response? I won't be able to enter that menu with the new panel installed since I have zero responsiveness from the panel unless there's a button sequence or another way to navigate there. Thanks again!

I didn't realized that when I've just cut and paste the content of the service manual :(

Yeah, that is dumb, of course you cannot touch <info> if the touch panel is defective and Roland did not provide any shortcuts for many of the touch features.

On the other hand, the calibrate touch panel function could also be accessed via the utility menu. If your new touch panel is somehow responding but off calibration you should be able to have some response on the utility screen as the 10 virtual buttons are filling up most of the screen.

Sadly I'm not aware of any other way.

LA