sudomod

Hello friends,

I'm trying to figure out why I can't get my Gearbest "new" variant board going. Sometimes I can see the backlight light up very faintly, and see the ghost of the "welcome" screen from Retropie, but it's so faint I can hardly see it. I read here that it will run off 5v without any modifications, so I have not done any modifications. The board is like the one newly added to the wiki called "new gearbest screen".

From ebay: https://www.ebay.ca/itm/3-5-Inch-TFT-LC ... 2658368607

Here is my wiring:
The whole thing: On the pi: I have wired the red power wire to the powerstrip, the white (also tried yellow) AV wire to the square TV pin on the pi, and the black ground to the circle TV pin on the pi. The pi powers up and because I can faintly see the image on the screen sometimes I am pretty sure that part of is fine. My multimeter has crapped out so I am kind of going along blind here until I can get new leads. I have unsoldered and re-soldered to check my joints, but I may still be doing something messy, it's like -10 degrees C in my garage and my hands are freezing!

Can anyone shed some light on what I might be doing wrong? Thanks for any input you can give me!

Hmm. I always use the yellow wire, but if you've tried that with the same result, hmmm...

Also double check the ribbon cable is seated all the way. And the white connector is plugged in all the way. You're working in a cold garage? Maybe bring things inside and let it warm to room temp...-10c is a little cold. Might be causing issues?

I also see the white wire is taped, is it spliced together undeneat that tape? If so, make sure it's a good soldered connection, not just twisted wires.
That's all I can think of...

The board says the yellow wire is AV2 and the white is AV1, but yeah, same result either way!

The ribbon seems to be seated and the white connector is snug. I soldered in the garage but brought in for testing, everything is warm now but I can still only barely see the edges of the screen when it starts up.

The white wire had a bit of a dent in the rubber casing, so I had taped it to keep it from splitting open. It's possible it's damaged underneath, but I would think that the yellow wire would still work in that case. Maybe I might take off the white connector and solder directly to the pads with some sturdier wire.

Thanks for the suggestions!!

Yeah. You could try direct soldering. That's what I typically do. Worst case you have a bad screen...eBay seller will hopefully refund. I've never had an issue where you kinda see the screen....

Please check the ribbon cable closely. There might be a tiny tear on the ribbon cable.

I had same problem with one of my builds, turned out there is a tiny tear on the ribbon cable near to the screen. The screen just got power and due to the tear would not get the signal. Got the replacement screen from Gearbest and it worked.

If the screen works then when powered up you would see either "AV1" or "AV2" display before the pi start to read from SD card. If you see nothing then I am afraid you have a duff screen.

My advice - return the screen....

Wow, thanks for that insight vnman. Although I had inspected the ribbon closely before, I went back on your suggestion and this time examined it under a magnifying glass - and sure enough there is a tear right on the edge of the ribbon where it connects to the pins. The plastic coating makes it look like it is still pressed up snug to the pin strip but under the magnifying glass I can see that the outermost and maybe second outermost traces are severed. Geez! It is such a tiny rip in such a place so I'm not surprised I totally missed it before.

I'm not sure I can blame the seller for this one, since several days ago my dog came ripping into the garage and knocked over my table and all my pi stuff went flying to the floor. It could have been damaged then.

I'm going to order another and I'll update you guys how it goes! Thanks again, vnman and rodocop!

I just wanted to come back and update that my new screen works great. I got the slightly older board so I had to do the 5v modification, but it seems like the tiny bit of torn ribbon in my first screen was the issue. Hope this info from my misfortune helps out someone else figure out what's happening if they can only see a bit of ghost-screen when they power on!