[SOLVED] BW variant 7

[MrErickson]

I've been trying for three days now to get a screen wired up for my GBZ project and seem to have hit a wall not once but twice. I have 2 BW 3.5" screens from Amazon, both appear to be the variant 7 board. I followed the screen clip for the mod listed on the Wiki, running a wire from power to the #2/SW pin on the XL1509 chip. When the first board didn't work after three attempts I thought I somehow toastered the board or screen and broke out the other screen i ordered, redoubling my efforts to be absolutely careful with it. Same result as the first, i get a wire ran to the chip and the screen in both cases was pitch black, no flicker, not a thing as far as i could see.

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::Edit::

After a break I restripped and tinned my wires and re-soldered everything, still no dice.

20180926_222604[1].jpg (3.84 MiB) Viewed 4174 times

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I broke out my multi-meter this morning and as far as i can tell the solder points seem good. Would my next step be to try and remove the XL1509 chip completely and then solder to the #2/SW spot? If so any suggestions for how best to remove that chip with it being such a tightly confined area?

I took a quick picture with my phone, I can grab my wife's DSLR for a better picture if needed. Any advice or recommendations would be appreciated.

Thanks!

[VeteranGamer]

try powering the unit off a separate 5V power supply....
(also maybe make that jumper wire as short as possible)

also i don't think you need to wire both AV cables (white & Yellow) to the Pi Zero, just one is enough....
(pick one, it will either be AV1 or AV2)


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[MrErickson]

I'll give that a shot tonight. Does the screen have any noticable flicker or glow when it is receiving power but no video source or does it require a video signal as well?

Thanks VeteranGamer!

[VeteranGamer]

I'll give that a shot tonight. Does the screen have any noticable flicker or glow when it is receiving power but no video source or does it require a video signal as well?

Thanks VeteranGamer!

not really...
when its on (gets power you'll know)....

another thing i didn't mention earlier was to check the ribbon cables, it looks like you've been disconnecting the LCD from the board...
ensure that its been reconnected properly (double check)




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[MrErickson]

I'll give that a shot tonight. Does the screen have any noticable flicker or glow when it is receiving power but no video source or does it require a video signal as well?

Thanks VeteranGamer!

not really...
when its on (gets power you'll know)....

another thing i didn't mention earlier was to check the ribbon cables, it looks like you've been disconnecting the LCD from the board...
ensure that its been reconnected properly (double check)

So far no dice, I hooked the pi and screen up via the Powerboost 1000 like they would in the build, I then tried powering the Pi and board separately. To eliminate the pi as the issue i wired the composite up and hooked it up to the composite option on an old XBox 360, no luck there either.

I will keep working with it and see what comes of it. I can still shorten the wire going to the 1509 chip a bit more and if that doesn't work I may take a stab at desoldering the chip.


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[loungemem02]

Have you tested the pi to make sure it works still. You connected both audio channels to the pi. The white wire connected to the video ground on the pi is also an audio channel. I fried a pi by reversing the ground and video signals on those connections you used.

[MrErickson]

I'll give that a shot tonight. Does the screen have any noticable flicker or glow when it is receiving power but no video source or does it require a video signal as well?

Thanks VeteranGamer!

not really...
when its on (gets power you'll know)....

another thing i didn't mention earlier was to check the ribbon cables, it looks like you've been disconnecting the LCD from the board...
ensure that its been reconnected properly (double check)

No luck so far with the 2 variant 7 screens I ordered but on a whim i ordered 2 more from 2 different vendors on Amazon, different from each other and from the vendor that supplied my original order. One of the second batch is a Variant 8 which I was able to move the power wire as indicated in the Wiki and it works like a charm, the board on the other doesn't look like any of the listen BW variants in the Wiki but does look exactly like the 'InnoLux' Ebay screen which I haven't done anything with other than open up to get a look at the board. I'll proceed with the V8 and continue to tinker with the V7s. I tried a different Pi0 board with the V8 and am wondering if maybe the TV port on the other Pi0 I used for testing isn't bad as it didn't work when I wired it to the V8 screen.

I appreciate your help! Thanks again.

[MrErickson]

Have you tested the pi to make sure it works still. You connected both audio channels to the pi. The white wire connected to the video ground on the pi is also an audio channel. I fried a pi by reversing the ground and video signals on those connections you used.

I did just that tonight with a different Pi0 board and it worked so I wonder if that isn't the case. The HDMI on the original Pi0 I used works but I don't think i've gotten a video signal out of it yet.

[MrErickson]

I'll give that a shot tonight. Does the screen have any noticable flicker or glow when it is receiving power but no video source or does it require a video signal as well?

Thanks VeteranGamer!

not really...
when its on (gets power you'll know)....

another thing i didn't mention earlier was to check the ribbon cables, it looks like you've been disconnecting the LCD from the board...
ensure that its been reconnected properly (double check)

Good news, both of the second screens are working like a charm and after stepping away from the V7s for a bit I got one of them working this afternoon after taking another stab at it. The remaining V7 is likely dead beyond my ability to fix it, an unfortunate casualty of young kidos horsing around in my office while I was at work.

Regardless thank you much for the assistance!