Good digitizer not working with old main board. What could be going on with the MB?

[BluegrassElectronics]

Good digitizer not working with old main board.

Samsung Galaxy S3 (i535 Verizon)
I am having an issue with a replacement lcd/digitizer not working properly with a certain main board.
I have several extra parts and was able to get full functionality with spare MBs but not when customers MB was installed.
The phone was functioning fine initially (after repair) for the first 24 hours or so but then the Touch screen became unresponsive.
swapped out MBs and touch works fine.
Swapped MBs back and lost touch.
Repeated this several times same results.

Phone has not been rooted and no apps were installed recently.
Any ideas as to what could be going on with the MB?

 

[Rukbat]

Re: Good digitizer not working with old main board.

It was probably wet at one time, or some part of the digitizer circuitry just decided to go bad 24 hours after you replaced the screen. I'd look VERY carefully for any signs of corrosion, pitting, oxidation of what's supposed to be shiny metallic surfaces. If anything shows, advise the customer that getting the phone wet has caused a lot of damage (even condensation will cause water damage - without setting off the markers).

 

[BluegrassElectronics]

Re: Good digitizer not working with old main board.

No obvious signs of damage. Screen still functional with alternate MB. I could swap out chips if i could find the layout to point out correct one for digitizer control.