JXD S7800B 16gb Screen issue, random screen presses and selections - Android Q&A, Help & Troubleshooting

Hi there, I have an issue wih a JXD S7800B handheld android console. When powered up it will randomly select things on the screen or scrolls.
I would like some advice from anyone who knows a bit more technical info on this as I'm an amateur to this.
1. Could this be due to a sticky physical button or thumbstick?
2. A faulty screen/digitizer ( repairable or not? )
3. The screen not being earthed correctly? I've heard static buildup can cause erratic behavior in other touch screen devices. If so where is the earth located on the JXD S7800B? And how would I fix it?
4. Where on earth can I get parts for this thing to repair it? Such as screen components and ribbon cables, batteries etc?
Thank you to anyone who could help me on this. The unit is virtually new and hardly used so it would be a shame to throw it away, although as I bought it second hand I'm pretty sure there's no proof of warranty if it had any.
Also I've heard JXD are pretty useless helping people with issues.
Thanks again.

Related

[Q] Rare Touchscreen Issue: Faulty Horizontal Line

Hey guys,
My screen woes just won't go away. I dropped my phone a few weeks back and cracked the screen. Ordered a new one from eBay (Item number: 260818538062) with the faceplate and everything. Had it installed but then started noticing that SWYPE wasn't working as well because my words would start breaking midway. Installed Yet Another Multi Touch Test and when trying to paint realized that there is a very evident line on my screen that isn't working as well. That was one continuous movement of slow up and down jestures but as you can see, the touch sensitivity is much weaker as well as the screen sensing a second touch at some point.
What can I do? I will gladly take the thing apart and clean the connectors.. if that will help. But somehow am inclined to believe that the issue lies with the screen. Is there a software recalibration fix that exists perhaps? Anyone experienced the same thing and walked away with a working solution?
Please help and thank you in advance.
(EDIT) I've added a second attachment where I started going around the outer edges working my way in, there's definitely one faulty line in my screen!
(EDIT2) Found a native Android touchscreen test (white and green) thanks to a member named BryanNL in a different post. Basically had to dial *#0*# and chose it from a menu. This test claimed that I passed but you can see that it is not made to tackle an issue like mine.
Bumping.. Anyone please.

[Explanation] Ghost touch

{ Disclaimer: the following text is my view about this problem. I'm not in any way responsible for any damage }
As there is very little info known about this phenomena I will try to explain it. I learned a lot of disassembly guides and by visualizing it (settings-development-show touches)
Ghost touch is a strange phenomena of various types and is due to a hardware fault between the mainboard connector and digitizer screen, I'm therefore trying to clarify it by categorizing them in three groups:
1. Small; Screen is unresponsive. 1 lock/unlock and it works again. Almost perfect. No need to replace screen. Most common.
2. Large; Same as 1, and often up to 5 touches and the touches are often moving/pressing parts of the screen. This can become a very frustrating period. Messaging apps and settings can be messed up by these touches. Often a lock/unlock will fix this temporary. A full screen replacement is recommended
3. Unworkable; Same as 2, and the lower and upper part are not working anymore. Notfications bar can not be pulled down anymore, typing become a nuisance and it not possible anymore and you curse your phone. Also it is not even possible to insert your pin, unlock your phone etcetera. This problem will not be fixed by a restart/reset or lock/unlock. A full screen replacement is essential.
Many people say this can be fixed by software settings, however this is a hardware fault. I tried many different roms and I encountered at all of them. The only fix that can be done to fix this is replacing of the full screen as it is not possible to apply/remove your digitizer.
For a long time I thought it was due to the degrading digitizer or something, in fact it is probably the connection between the and the mainboard. The screen has two digitizers: One for the touchscreen and one for the home/settings/back/search buttons. For some reason this last one did not cause any trouble. The first one has a flex cable from the upper part of the screen leading toward a small hole and heading to the mainboard. The problem will probably reside in the part between the digitizer and the small hole. Here, just above the screen, the flex cable is folded 180 degrees. This fold will cause the problem as it is very sensitive. Mine has a very small damaged part, the copper parts are visible. The cause of this is due to the rubbing of the bezel just under the speaker.
How to fix it?
Buy a new screen including digitizer (often HTC & Sprint branded) and make sure you protect this part as much as you can.
EDIT:
I re-inserted my old LCD display with a bit of tape around the damaged part. Since then I haven't had any ghost touches.
Mine was ghost touching so bad it was completely unusable for a few days. I was thiiiiiiis close to buying a new phone, then one day it just stopped and hasn't done it again since. Very strange. Anyhow, I will be replacing it with an s4 when the price comes down to $100 for us SERO users.
Ghost touch
Nice explanation, and nice 3 lvl sorting but, tell me one thing... I have experience with lvl 1 and 2 (two different phones) and for both of them simple ROM change / reinstall helped to solve this problem.
For ex. I had JB [ROOTBOX] ROM since the last week.. ghost touch problems were getting worse and worse with each new day yet lock/unlock still worked quite well.
I decided to test new JB MIUI ROM and like a magic touch my ghost friend is gone since than, but I am afraid he will return more powerfull than ever... oops that is a different story. However my phone is now working fine ... no ghosts detected.
So please don't tell me that this problem is only mechanical problem ( due to ROM change / reinstall worked multiple times). Actually I am pretty sure that is software problem which is supported by hardware hitches.
My friends "ghost story" is pretty similar.. but he reinstalled back original ICS ROM.
PS: I don't want to start flame war with this reply. It is just mix of my experience and opinions.

[Q] HELP! Problem with my Samsung Galaxy A5!

Hi,
As mentioned above, there is a problem with my A5. When my tempered glass screen protector is fixed and when my phone is charging, my touch screen seemed to go haywire. I am holding my finger in one place but the phone detected that my finger is shaking, wildly. Besides shaking, my phone will stop sensing my finger even though it is held there.
I doubt it is the problem with my hardware because I have already changed the touch screen, charging port and the motherboard by sending it to the Samsung Service Centre. I believe the problem is due to the tempered glass (my previous tempered glass) because it was put onto another A5 and the same problem occured. Now, I have purchased another tempered glass from REMAX (picture below), and it seemed to cause the same problem again.
So now my questions are
1. Can I seek for another alternative such as Spigen's tempered glass screen protector or should I just use the normal screen protector?
2. Am I the only one facing this problem?
3. Is the problem really due to the tempered glass?
Oh by the way, my phone is running on official rom version 4.4.4.
http://76.my/Malaysia/[email protected]
JssCheonGz said:
Hi,
As mentioned above, there is a problem with my A5. When my tempered glass screen protector is fixed and when my phone is charging, my touch screen seemed to go haywire. I am holding my finger in one place but the phone detected that my finger is shaking, wildly. Besides shaking, my phone will stop sensing my finger even though it is held there.
I doubt it is the problem with my hardware because I have already changed the touch screen, charging port and the motherboard by sending it to the Samsung Service Centre. I believe the problem is due to the tempered glass (my previous tempered glass) because it was put onto another A5 and the same problem occured. Now, I have purchased another tempered glass from REMAX (picture below), and it seemed to cause the same problem again.
So now my questions are
1. Can I seek for another alternative such as Spigen's tempered glass screen protector or should I just use the normal screen protector?
2. Am I the only one facing this problem?
3. Is the problem really due to the tempered glass?
Oh by the way, my phone is running on official rom version 4.4.4.
http://76.my/Malaysia/[email protected]
Click to expand...
Click to collapse
Without getting into too much tech details i have a list of possible cause's
1. with having a additional screen cover in place and power connected your body+screenprotector create a capacitor, this is exactly how the screen registers touch , so without the screen protector in place this wont happen. I've seen this on a few Screen protectors that use certain types of conductive glue/bonding agent.
2. faulty charger or fake chargers often cause this behavior, try another charger or use USB on a laptop not plugged into mains power, if the problem is gone then plug in laptop's main power, if problem still gone then your issue is charger, if problem starts when pluging in the laptop's power then it's either ground loop or your screen protector acting as above.
3. faulty assembly when fitting screen, they didnty apply the copper back shield or the protective cloth that act's as a shield around the ribbon cables
before anyone shouts that samsung fixed it, I know and i can quote many a occasion a cell phone was not fixed right first time by the OEM
if you activate developers options and switch on show touches then repeat the test , does the display always show certain areas that register touch , if so it can also show where the bonding agent has a airgap, this adds to the capacitor effect.
finally try wearing shoes when touching the screen, if wearing shoes stops the problem get your house wiring checked.
darkspr1te
gua rasa pasal charger lu tu bro. try tukar charger atau cable lain.
saxmydix said:
gua rasa pasal charger lu tu bro. try tukar charger atau cable lain.
Click to expand...
Click to collapse
thanks saxmydix, i used multiple chargers and it is still the same, i tried charging in another house in another area, still the same problem occured, so i doubt it is the problem with my charger.
thank you for your time and i appreaciate it a lot
darkspr1te said:
Without getting into too much tech details i have a list of possible cause's
1. with having a additional screen cover in place and power connected your body+screenprotector create a capacitor, this is exactly how the screen registers touch , so without the screen protector in place this wont happen. I've seen this on a few Screen protectors that use certain types of conductive glue/bonding agent.
2. faulty charger or fake chargers often cause this behavior, try another charger or use USB on a laptop not plugged into mains power, if the problem is gone then plug in laptop's main power, if problem still gone then your issue is charger, if problem starts when pluging in the laptop's power then it's either ground loop or your screen protector acting as above.
3. faulty assembly when fitting screen, they didnty apply the copper back shield or the protective cloth that act's as a shield around the ribbon cables
before anyone shouts that samsung fixed it, I know and i can quote many a occasion a cell phone was not fixed right first time by the OEM
if you activate developers options and switch on show touches then repeat the test , does the display always show certain areas that register touch , if so it can also show where the bonding agent has a airgap, this adds to the capacitor effect.
finally try wearing shoes when touching the screen, if wearing shoes stops the problem get your house wiring checked.
darkspr1te
Click to expand...
Click to collapse
hi darkspr1te,
thanks for ur response.
1. so it is entirely dependent on how the screen priotector/tempered glass is sticked to the screen?
2. sorry for not including the details on my charger in my post. i am currently using an official charger that i got when i purchased my previous samsung phone(S2 gt-i9100g). i tried using the A5 charger and the problem persists. will using a powerbank recreate the scenario of the unplugged laptop charging? if it is the same, the problem is still there even when my powerbank is unplugged. i do not have a laptop at home and it wouldnt be possible for me to get my hands on a laptop that i can use these few days. i tried charging my phone in another house (in another region which is like 20 kilometers away) and it is still the same. and my brother's samsung galaxy alpha do not have this problem while charging.
3. so u are saying that the problem might be due to oem? once again i apologize for not including this in the post. while i am at the samsung shop, the person in charge tried putting the tempered glass (which was fixed to my phone) onto another A5 which was there due to a boot loop problem, and it started to have the same problem. is it possible that all Samsung A5's assembly do not have the copper back shield or the protective cloth?
apparently nobody in the samsung shop knows how to deal with my problem because they have never seen it before. it took me quite some time to explain to each person who attempted to serve me and i only managed to show the problem to one of the personnel (which was the one who helped me fix my phone). i went back to the samsung shop 3 times in 2 days. in the 1st time, he changed the touch screen, in the second time, he changed the charging port and in the third time, he changed the motherboard.
as for the test, i turned on the pointer location and i keyed in *#7353#, and i selected TSP grid mode. that is how i checked the problem. and while i was there, the shaking only occurs at where my fingers are. i tried enabling the show touches option and the display do not register touches until i touched them.
i doubt it the the problem with my house wiring since it is the same with my other house but thanks for the suggestion. i will definitely try wearing shoes when i am at a different house. maybe both my house got wiring problem.
i learnt a lot from your post. thanks for your time and i hope to hear from u soon
JssCheonGz said:
hi darkspr1te,
thanks for ur response.
1. so it is entirely dependent on how the screen priotector/tempered glass is sticked to the screen?
Click to expand...
Click to collapse
It wont be 100% of the cause but will affect performance of the screen.
2. sorry for not including the details on my charger in my post. i am currently using an official charger that i got when i purchased my previous samsung phone(S2 gt-i9100g). i tried using the A5 charger and the problem persists. will using a powerbank recreate the scenario of the unplugged laptop charging? if it is the same, the problem is still there even when my powerbank is unplugged. i do not have a laptop at home and it wouldnt be possible for me to get my hands on a laptop that i can use these few days. i tried charging my phone in another house (in another region which is like 20 kilometers away) and it is still the same. and my brother's samsung galaxy alpha do not have this problem while charging.
Click to expand...
Click to collapse
Yes, using a non-mains connected charger will be sufficient for the test, like your power bank for example
3. so u are saying that the problem might be due to oem? once again i apologize for not including this in the post. while i am at the samsung shop, the person in charge tried putting the tempered glass (which was fixed to my phone) onto another A5 which was there due to a boot loop problem, and it started to have the same problem. is it possible that all Samsung A5's assembly do not have the copper back shield or the protective cloth?
apparently nobody in the samsung shop knows how to deal with my problem because they have never seen it before. it took me quite some time to explain to each person who attempted to serve me and i only managed to show the problem to one of the personnel (which was the one who helped me fix my phone). i went back to the samsung shop 3 times in 2 days. in the 1st time, he changed the touch screen, in the second time, he changed the charging port and in the third time, he changed the motherboard.
as for the test, i turned on the pointer location and i keyed in *#7353#, and i selected TSP grid mode. that is how i checked the problem. and while i was there, the shaking only occurs at where my fingers are. i tried enabling the show touches option and the display do not register touches until i touched them.
Click to expand...
Click to collapse
Yes,
Galaxy Alpha Images
Note on images 4 and 5 you will see the copper shield, this model does not have the conductive cloth I mentioned but the copper ground plane can clearly be seen on both the body and screen. Fake and non oem parts tend not to have this, in the body there is also a copper area which can be removed by mistake on replacement of the screen.
this is not often found in the replacement screen kit.
i doubt it the the problem with my house wiring since it is the same with my other house but thanks for the suggestion. i will definitely try wearing shoes when i am at a different house. maybe both my house got wiring problem.
i learnt a lot from your post. thanks for your time and i hope to hear from u soon
Click to expand...
Click to collapse
if it's happening at another location then you can discount this theory.
I am still leaning towards incorrect parts or assembly as this is the cause I personally see most often and i've repaired a LOT of damaged phones. As you have stated you have more or less a complete new phone if they replaced screen+motherboard.
I once repaired a phone that had been back to the OEM service center, cause of fault was copper strip from old screen touching the board, the copper slip was so small i only noticed it when it sparkled under the right light, it's mistakes like that is what I am talking about, easily missed by many.
darkspr1te
how do i check if my phone has the copper strip or not?
i am going to bring my phone to the samsung store tomorrow and hope for some answers regarding the copper strip. thanks darkspr1te
how do i check if my phone has the copper strip or not?
i am going to bring my phone to the samsung store tomorrow and hope for some answers regarding the copper strip. thanks darkspr1te
darkspr1te said:
It wont be 100% of the cause but will affect performance of the screen.
Yes, using a non-mains connected charger will be sufficient for the test, like your power bank for example
Yes,
Galaxy Alpha Images
Note on images 4 and 5 you will see the copper shield, this model does not have the conductive cloth I mentioned but the copper ground plane can clearly be seen on both the body and screen. Fake and non oem parts tend not to have this, in the body there is also a copper area which can be removed by mistake on replacement of the screen.
this is not often found in the replacement screen kit.
if it's happening at another location then you can discount this theory.
I am still leaning towards incorrect parts or assembly as this is the cause I personally see most often and i've repaired a LOT of damaged phones. As you have stated you have more or less a complete new phone if they replaced screen+motherboard.
I once repaired a phone that had been back to the OEM service center, cause of fault was copper strip from old screen touching the board, the copper slip was so small i only noticed it when it sparkled under the right light, it's mistakes like that is what I am talking about, easily missed by many.
darkspr1te
Click to expand...
Click to collapse
how do i check if my phone has the copper strip or not?
i am going to bring my phone to the samsung store tomorrow and hope for some answers regarding the copper strip. thanks darkspr1te
JssCheonGz said:
how do i check if my phone has the copper strip or not?
i am going to bring my phone to the samsung store tomorrow and hope for some answers regarding the copper strip. thanks darkspr1te
Click to expand...
Click to collapse
Sadly that can only be done by removing the screen. I dont suggest you try, ive seen the disassembly video, it's tough, one time job and if it goes wrong it's bye bye screen.
darkspr1te
darkspr1te said:
Sadly that can only be done by removing the screen. I dont suggest you try, ive seen the disassembly video, it's tough, one time job and if it goes wrong it's bye bye screen.
darkspr1te
Click to expand...
Click to collapse
I sent in my phone to the samsung store to check the charging port (which is also making some problems), and i requested them to check the copper shield.
while i was there, i realised there is another phone which has the same problem as me. could it be that all the A5 model has the same problem ? :/
JssCheonGz said:
I sent in my phone to the samsung store to check the charging port (which is also making some problems), and i requested them to check the copper shield.
while i was there, i realised there is another phone which has the same problem as me. could it be that all the A5 model has the same problem ? :/
Click to expand...
Click to collapse
I don't think it's the phone model, we would see more reports if it was, I would enquire if the other unit also had screen changed. If it has then one might assume pirate parts, no way to prove that without checking back of lcd for the oem barcode sticker. The is on possibility I only just thought of, a while back I had a client bring me a i9505 that the oem changed screen on, I just reread the emails between us and the fix was replacing the screen with a i9505 screen, the oem locally only supplies i9500 devices so they only fitted a i9500 screen, turns out there is a difference in the touch chip, I was able to prove this by attaching the touch only circuit from his old screen. No more random touches.
From this I can assume the various SM-A500 models use different touch chips. Or slightly different firmware in the chip, I have seen that before on the rock chip based tablets I support here.
Darkspr1te
darkspr1te said:
I don't think it's the phone model, we would see more reports if it was, I would enquire if the other unit also had screen changed. If it has then one might assume pirate parts, no way to prove that without checking back of lcd for the oem barcode sticker. The is on possibility I only just thought of, a while back I had a client bring me a i9505 that the oem changed screen on, I just reread the emails between us and the fix was replacing the screen with a i9505 screen, the oem locally only supplies i9500 devices so they only fitted a i9500 screen, turns out there is a difference in the touch chip, I was able to prove this by attaching the touch only circuit from his old screen. No more random touches.
From this I can assume the various SM-A500 models use different touch chips. Or slightly different firmware in the chip, I have seen that before on the rock chip based tablets I support here.
Darkspr1te
Click to expand...
Click to collapse
this is getting a little too complex for me to understand, let alone explaining it to the samsung guy. are u trying to say touchscreens from different variants of A5, such as SM-A500G is being fitted into my SM-A500F?
JssCheonGz said:
this is getting a little too complex for me to understand, let alone explaining it to the samsung guy. are u trying to say touchscreens from different variants of A5, such as SM-A500G is being fitted into my SM-A500F?
Click to expand...
Click to collapse
Yes, that's exactly what I am saying. Although it's only a theory based on prior solutions, I dont have any proof to hand other than my experience.
darkspr1te
Battery issue
My galaxy A5 have some battery issue. It won't charge after 88%,and didn't turn off after 2%. The phone is turn on over night at 2%..please help me regarding this issue.

No display

Hi,
I come to you concerning a problem of display following a change of screen.
I explain: After the breakage of the screen, I ordered one and I installed it in the defective place. Before the final editing, I wanted to test it. The phone vibrates well at startup and it is well recognized by the PC but there is no display. I first thought of a problem with the connectivity of the ribbon cable. So I reverified everything and reconnected everything but the result remained the same. So I contacted the supplier who sent me another screen but I still do not have a display.
An idea about the problem?
Thank you in advance for your answers.
Sincerely,
Might be the phone.
Hello there,
I've had this same exact problem with my M4 Aqua (E2353) and I did order a few different screens from many different sellers, but still no luck. I later found out that it was the Pin Connecter in the Phone , not the Ribbon or the Replacement screen. I took it into the Dealers, since I still have my Warranty, and they gave me a replacement for my Phone, since I cannot wait for my damaged phone to be repaired. You might wanna look into the phone area.
Cheers!
Hi,
Thank you for your answer.
Indeed, I just looked more closely and I realized that there are two or three CMS components missing at the LCD connector (see picture attached).
Link to the image : hpics.li/0c2a510
Do you think it is repairable?
Regards,
Doesn't look like it's repairable by you, since it's a very sensitive part. I suggest you take it into the dealers to repair, before any accidental damage is done.
Hope I helped!

S7+ screen way too sensitive

Just got a new Tab S7+, and I found that I was getting a heck of lot of repeating keys from the Samsung keyboard and the Gboard keyboard. Hadn't noticed any problems elsewhere.
I finally got fed up with it and get Touch Screen Test, and I can see clearly there that the screen is registering a touch with my finger maybe 0.5mm away from it. That fits with what I see on the keyboard, where I can get keys to fire with tiny finger movements just away from the screen.
I can't find any settings in Android 10 to adjust this. It's surprising for a table that's been out of the box a couple of weeks, and possibly it's worsening.
I had an idea after I'd posted this - I often use the tablet connected to the 25W charger that came with it. If I use it on battery, the problem is much diminished , and possibly gone. Electrical interference, then???
Is it a return-as-faulty, would you say? Any test options I can use to help with this?
Thanks
Alan
Latest update fix that issues
bicubic said:
Latest update fix that issues
Click to expand...
Click to collapse
Many thanks for that. My tablet has T970XXU1AT12 / T9700XM1AT12, no update showing as of a moment ago. I expect it will reach the UK soon and I will be able type!!
I think the touchscreen of this tablet does have some interesting behaviors, as I've also observed some touches being registered when my finger was a still a short distance away. I suspect this might have something to do with palm-related gestures (like palm swipe from right to left for screenshooting).
I play rhythm games on this tablet mostly, and I'm seeing some cases of taps not being registered properly (unexpected misses), which happened less often, when I was playing those same games on my phone (before migrating them to the tablet).
I don't constantly put the tablet on the charger, as I've lessons learned from my previous tablet, Pixel C, whose battery went swollen after having placed it constantly on the charger for quite a long while that I ended up replacing the swollen battery with a new one by myself. While it was a lot of effort in overall, but the swollen battery had made the glues between the screen and the chassis mostly visible, that removing the screen became much easier.
I couldn't confirm this issue.
I've installed a safety glas on top of the screen. Fingerprint and S Pen is working but I've no issue's with a to sensitive Display
Update came yesterday. Still not fixed
I'm also using a tempered glass screen protector and my personal experience with such protectors on different devices has always been positive, with few issues directly related to such protectors as long as the quality appears to be good enough. I don't connect the charger while gaming, but I do attach a Type-c audio cable for connecting the tablet to desktop speakers.
On the other hand, some lower quality charging cables would certainly cause issues with touchscreens regardless of device. Usually with stock chargers and cables (or those from very reputable vendors) you can mostly rule out this possibility.
EDIT 6: Moved the rest of the issues I'm having to a separate thread.

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