This 10" BUSH Spira B1 Android Tablet was sold on e-bay as "Not Working - for parts" so I decided to take the challenge and see if I could delve into it's innards and fix it.
It was a simple but interesting diagnosis with a satisfying end result.
The tablet appeared to be taking a charge, as seen when a charger was plugged it but the power on/off button had no affect, no power on, no change in the charge display when pressed.
So where to start? The previous owner(s) had obviously been inside the device as the casing was damaged around the edges, I following their lead, I inserted a plastic spudger and prised the casing apart. I was relieved to see that the main PCB did not appear to have been tampered with, no fresh solder on the chips or other components. I suspect they were looking to somehow retrieve the data stored in the EEPROM RAM that the device uses.
So this lead me to why the device would not power on but the display was obviously good. Looking at the power and volume buttons, I could see these were on a small strip and used the springy metal contacts, like those used on some car key fobs. I found this strip was connected by a ribbon cable which was - thankfully - plugged into the PCB via a small ZIF and clamp connector. Lifting the clamp I could pull out the ribbon. As there did not appear to be any electronics built into the ribbon, I suspected the buttons were a simple matrix of the switches. I forced the power switch closed with a mini bulldog clip and tested for continuity between the end of the ribbon. I had to use some needle test probes as the ribbon was very small and ordinary probes would have been too big to connect. I could find no continuity between any of the pins.
Next I pulled off the cover which held the springy buttons to reveal the contacts beneath and then traced continuity back to the ribbon. The centre of the power was traced to pin 2 but the outer failed to connect to any contacts on the ribbon. The final result of the checks are shown below:
Repairing the ribbon is practically impossible so I decided to bypass the ribbon with a fine wire, soldering one end to the outer side of the reset switch which is shared with the power switch and the other to a ground on the outside of the board connector which traced to pin 6 of the connector.
Having done that and partially reassembled, I was pleased to find the device now powered up and was totally usable.
As expected there was some original user data on the device, email addresses, photos and a video. I sent an email asking if they wanted me to send it to them but they never replied. I then did a full factory reset of the device, wiping all other user data and set it up for my own use. It's a 2016 model and runs Android 6 which is now very old and cannot be updated, but it works and will be a useful test device or spare for emergencies. I may even get another sent to me for repair so could salvage parts from this one to do other repairs.
So a simple fault, difficult to trace, the ribbon could not be repaired and trying to get spares for these from the original supplier ARGOS is impossible. But a satisfying repair nonetheless. Hope you enjoy the video which I've trimmed down to the shortest possible.