C91 Update (1a) Touch Screen Problems

[Ishtar]

Dear All

I'm afraid that my tablet has been inflicted with the infamous touchscreen problem. I have updated the firmware both with and without autoscrip, I have attempted this countless times. I have also taken my tablet apart and checked the ribbon cables, calibrated the touchscreen via the volume up key and the captouch function. I have tried various custom ROM's and earlier versions of the official Zenithink ROM and even tried flashing the touchscreen controller.

Sadly, all to no avail.

My problem in more detail:

At first my touchscreen simply stopped responding across the entire display. However after playing around with the above procedures I managed to get over half the touchscreen working but alas not the other half. I have researched this problem in-depth and now tried just about everything. To make matters worse my supplier is giving me the run-around.

Has anybody else experienced half the screen not responding to touches? If so, is there a fix? I now suspect that my touchscreen has died leaving me little option but to send the thing back to China.

I appreciate any help offered.

Regards
Ishtar

 

[Bas]

Hey Ishtar

Whilst I've not personally had that issue, it has cropped up before here and on other forums. Seems like you've tried quite a few solutions, was going to suggest opening the device but re-read your post and you've done that as well which leaves few options.

What does the supplier have to say?

 

[windeguy]

I purchased the same tablet in March of this year.
Problem is that the touch screen on my Zenithink ZT-280 C91 3a version makes random selections of icons several times a second. Either the software and/or the hardware that manages the capacitive touch screen is causing the problem. This started with an occasional jitter. With an update to the latest version of Android ICS which I had hoped would stop the problem, the tablet has become unusable. I have had the unit since March and this is a problem that happened over the past two weeks.

I am a former embedded microprocessor development engineer, so I am quite used to debugging hardware and working alongside software developers.

I used the firmware from

http://www.zenithink.com/Eproducts_C91.php?download

I have flashed the latest version of ICS (314 I believe ) from Zenithink.com, flashed the patch that is actually supposed to help jitter specifically happening on the 3a version of the ZT-280 C91 and even flashed an earlier non ICS version Version 2.3, 0217 version. There is so much jitter on the screen in all cases that the tablet is unusable. I opened the unit and reseated the cables without improvement. Even when I plug in a USB keyboard, I have random selections made on the screen.

Is there a way in addition to changing the version of operating system where I can perform a master reset and start all over? If so, what is the procedure?

I am also trying to contact the vendor. This appears to be a problem on a numbe of this exact model.

 

[ascari82]

It seems like touchscreen problem on C91 is just a question of time...there are so many posts on the web about this issue but no solution!
My touchscreen simply stopped working last week. I tried to check the touchscreen ribbon inside, but it looked ok. I finally installed latest firmware but nothing changed.

I'm really afraid I have to send it back to china (that means, I perhaps will see it back home in not less than 3-4 months). Next time I will be more prudent when buying online.

 

[ascari82]

UP! Any solution?

 

[WaveWeasel]

The sad truth is that Zenith used to be a great customer service oriented company. This problem has been around since March 2012. Most sellers will give you a month of warranty and although you still have a year from the manufacturer, they seem to refused to help you. I have been waiting for a positive response for six (6) months. Neither Zenith Corp nor their supplier down under seem to give a hoot. Try to get a good address from China, ship it to them and hope it gets repaired... This ZePad seems to be the biggest mistake for buyers to be suckered into.... Good Luck

 

[davebritton]

I've had the same problem. My touchscreen died the second day I had it. I upgraded the firmware successfully, but it made no difference, the touchscreen still does not respond to any touches. I could not get Zenithink, AliBaba or Ebenda (where I bought it) to give any support, except they insist I must pay to ship it back to Shenzhen China at my own expense. This would cost me $55, which is more than 1/3 of the cost of the tablet, and not worth it. So I do not recommend anyone to buy Zenithink products or deal with Ebenda Technologies until there is prepaid shipping for warranty returns, and service within the United States.

 

[davebritton]

I took the tablet apart today and discovered that the ARM cpu is extremely hot! it had burned a dark spot into the inside of the white case inside back, and you can see a bubble or pimple of disturbed casing on the outside of the chip itself. The video display shows an oval faintly fuzzy area just above the cpu chip also. I wonder if this is the root cause of the problem. It turns out that my audio is also not working at all, neither with or without earphones, which I had not noticed before, since I did not try to play movies or songs. This is a very disappointing tablet, given its great specifications and low price. Too bad it is so poorly made and unsupported.

 

[harrylukes]

This update is like a precious gift for me as I was waiting for these sort of features for my Android phone. The appearance of my Tough Screen phone is doubled with this and would like to have some more details regarding the latest updates. Thanks for sharing the info.

 

[sugees69]

I have read all of the post regrading this issue of the touch screen and I agree with all of you. I personally have not tried anything much yet, except for looking for answers. My first thought was that the tablet over heats to easily and that is causing the problems. I use my usb and mouse combo to use the table at all. As of yesterday I can no longer get on the internet, but I can download from the Google Play site, that doesn't make much sense to me. I can't use any browser to get on-line to try and do any downloads. So if I find any answer to these issues, I will post them ASAP. Good luck to us all, and don't by cheap anymore. Chinese products suck.