Unresponsive LCD Screen - Riso MZ 790U

[gillje]

Has anyone ever dealt with a unresponsive lcd screen on a Riso before?

I was printing earlier today when suddenly it stopped working. I tried test mode 1104: LCD Base Point Compensation to calibrate the screen but even then it wouldn't respond to touch.

Is replacing it the only thing I can do?

[Iowatech]

Re: Unresponsive LCD Screen - Riso MZ 790U

Have you searched this forum for info on how to reset the machine? You might try that before you replace anything,

[ddude]

Re: Unresponsive LCD Screen - Riso MZ 790U

I have not heard of RISO touch screens having problems, but there has been problems recently with every other manufacturer having touch screen issues, so it would not surprise me. Use the search feature in other sections of this forum, you will see other touch screen issues. This does not mean for sure that you have the same issue, I would also suggest you try a reset.

[gillje]

Re: Unresponsive LCD Screen - Riso MZ 790U

Yes, I have both held down reset when starting up the riso and punched in the code for unit initialization in test mode... still no response. Is there another way to reset? I'll look into lcd problems for the other manufacturers, thanks.

[Iowatech]

Re: Unresponsive LCD Screen - Riso MZ 790U

Yes, I have both held down reset when starting up the riso and punched in the code for unit initialization in test mode... still no response. Is there another way to reset? I'll look into lcd problems for the other manufacturers, thanks.

Well, you might try checking the wiring harnesses between the touch screen and the main board in the back. I haven't seen it for some time, but back in the day (GR line and the likes) the cable wraps sometimes were too tight, and would cause connectors to become unseated due to the machine's normal vibration.
Otherwise, I think that the MZ can print a list of the service mode adjustment points, and if you can get one of those you might try the more aggressive resets and then just input the data from the printout (I think the list is quite long though, and on the RN line at least the resets would change the display language to Japanese, so have some patience for this procedure if you choose to use it).
But it does sound like you do need to replace that touch screen.

[gillje]

Re: Unresponsive LCD Screen - Riso MZ 790U

Update*

I was able to find and replace my lcd touchscreen with one from another working MZ. It worked great for about 3 weeks, and then again it went dead ie not responding to any touch. At first only in certain spots, then the whole screen. It came back to life a couple of times, kind of randomly... but has totally stopped responding since then. I checked and reseated all the connections between the screen and the main board, but it still isn't responding to any touch.

Any ideas on what the problem could be, I mean besides the screen itself (I imagine the problem is with the wiring or the main board since it's happened to 2 screens now... right ??)