Possible fix for defective 3.5" displays

[G4WIM]

As mentioned in another thread I had more than a bit of trouble trying to get my display to work correctly and reliably.

After much faffing around I discovered that 3 of the 26 connector pins on the back of the display were intermittent.

They had not been soldered and thus relied purely on friction and good luck to connect.

Fix was simple, I just made sure they were firmly pushed into their respective via holes as far as they'd go.

The via hole is effectively 'blind' due to the close proximity of the screen and so re-work soldering isn't possible.

Bottom line - if you have one of these displays and it's not working, it might worth checking the connector.

[g0mjw]

Thanks for the info - my first screen was faulty too. Trying to fix it I found you can prize the screen off its PCB, it is held on with double sided tape. A think piece of this tape is preventing short circuits. Not what I would consider a good design. I will check for poor contacts and maybe improve on the mounting.

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Post note - all contacts were OK and it didn't fix the no-touch response problem. Its just junk and I won't buy from that Amazon supplier again. However, the cheap screen from China, that also came with a case for half the price, works fine.

[G4KLB]

Touch screens that don't work, often have damage to this flexible PCB.
This one was damaged fitting it into the case it came with!
But often caused by pushing on the cable when plugging it in and out of the Pi.

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[G4KLB]

I managed to fix this one, but its not easy

Scrapped down to the copper with a scalpel.

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soldered a wire across.

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Will strengthen with epoxy next.

[G4KLB]

Job Done.

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Not pretty, but its not like anyone will see it