G-boy rev 3 Screen flickers on then off

Jmoney

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Hello,
I'm at the end of step 13 in the guide (Testing the trim) and having an issue with the screen. When I boot the unit on, the screen lights up for half a second then shuts off. When I hook up the controller board to the screen and press the source button, I get another (even shorter) flicker of light and the screen shuts off again. I checked all the voltage lines are reading correctly and confirmed the screen is grounded common with the other boards.

I have no reason to believe U10 is bad and I followed this guide exactly: https://bitbuilt.net/images/guide_hub/console_modding/wii/ss_definitive_wii/u10_u5.png
Confirmed 3x over and all connections tested.

In another post I made (https://bitbuilt.net/forums/index.php?threads/g-boy-rev-3-board-trim-too-deep.4972/) I had trimmed a little too deep on one side of the board and cut through the NAND traces, I have since repaired those and confirmed continuity/no shorts. I'm not positive there isn't anything I missed there though so thought it was worth pointing out.

Any thoughts/ideas on what could be wrong would be appreciated.
 

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Stitches

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This one exposed NAND trace concerns me
1652764775152.png

It's possible that even though it registers continuity from leg to via, the trace doesn't have the integrity to transmit data correctly. I'd sever that trace and replace it with some magnet wire, just to be sure
 

Jmoney

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Thanks for the suggestion! So those NAND traces do play a part in screen function?

Definitely fair to be concerned about that one trace since it's right on the edge of the trim and exposed. I did verify continuity multiple times over but didn't compare actual resistance to an intact trace. I have my doubts that jumpering it will solve the issue, but I'll give it a go and report back since I'm out of ideas. Won't be until this evening though.

Another bit of info I forgot to provide is that everything else so far works fine (fan, USB, and charging).
 

Jmoney

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Okay I repaired that last suspect NAND trace and the result is the same. Screen still flickers a bright light on power on then shuts off.
Any other ideas?
Is it possible the screen is just bad?

I haven't tried using the composite cable yet, but is it just as simple as just hooking up the yellow video line to something else (like a working Wii for instance)? Will that override the video coming from the trimmed board or would I need to temporarily disconnect the G-boy video lines (which in my case would be the orange/purple wires, I think)?


That will be my next step unless I get any new suggestions. Thanks in advance for your support!
 

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Jmoney

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Looking at the screen board more, I'm noticing some differences between it and what's in the guide.
There is a diode missing on mine that is present in the guide, and a resistor is in a swapped adjacent position. See below for more context.
I might try reflowing some joints and probing around for issues. If anyone has any schematics or knowledge of what could cause power issues/how to troubleshoot please let me know!

1652825145372.png


1652825160191.png
 

dababy

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Thats screwed up af. I would def try to redo those errors on the board to look like the one in the guide cuz mine definitely did not look like that
 

Jmoney

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Best I can try now is reflowing solder joints and potentially relocating that one resistor. I do not have nor know the spec's for the diode so not sure what I can do there. I was under the assumption that they sent out different board/component configurations which would explain minor differences like this, however by no means am convinced there is not a factory error especially given the solder quality on the board. For now I will reflow some solder joints and check again. If anyone has a schematic for the screen board that would be invaluable--or any other info for that matter... Especially since product support from the creators is long gone.
 

Stitches

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Thanks for the suggestion! So those NAND traces do play a part in screen function?

Definitely fair to be concerned about that one trace since it's right on the edge of the trim and exposed. I did verify continuity multiple times over but didn't compare actual resistance to an intact trace. I have my doubts that jumpering it will solve the issue, but I'll give it a go and report back since I'm out of ideas. Won't be until this evening though.

Another bit of info I forgot to provide is that everything else so far works fine (fan, USB, and charging).
It's not so much screen function as it is any function. The Wii won't do anything with a scuffed NAND line.

I'm not sure what else to suggest. The issue you describe sounds just like a short, but you said you checked everything for shorts and found none. Have you checked the PMS outputs to ensure they're all outputting the correct voltage?
 

Jmoney

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Thanks for the info!
I haven't found any shorts but won't claim I couldn't have missed something.
I did check the PMS 1V, 1.15V, 1.8V, and 3.3V against ground and all are reading correctly.
I also followed that guide to check resistances between all voltage lines and ground on the Wii board back when I first trimmed it, and again now that I'm having issues. Both times everything read in the correct range.

Given this, I'm suspecting the screen itself is bad but not sure how to prove that. and again it's entirely possible I could be missing something obvious but am having a real struggle here nailing it down!

Ref to my last replies, I did reflow all the solder joints on the screen board to ensure a good sodler connection, but the same issue persists. I have not started switching components to match what I saw in the guide (yet--as stated earlier I don't have the diode shown in the guide).
 

Stitches

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I'd definitely test the screen with another video source if possible, just to rule it out as an issue. Any composite signal from another console would do. Also if you want to check the resistances again, you need to remove the battery from the PMS and disconnect the PMS from the Wii. Can't take accurate readings while it's connected and powered
 

Jmoney

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Do I need to disconnect the video lines going to the trimmed Wii board before plugging in the composite to another console?
Also am assuming the barrel jack is to give 5V to power the screen but I don't have an power supply for this, so would need to rely on the battery in the Gboy which I don't know is ending up powering the screen properly since it shuts off right away..

1652838527610.png
 

Jmoney

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Breakthrough:
Somehow removing the small ground wire to the screen solved my issue. The TP50 pad where that small wire originates on the Wii still has continuity with the common ground through the AWG22 wire from PMS to screen (blue wire in my case). I can't make sense of why this solved the problem nor why it was an issue in the first place. But am happy the screen is turning on now. Naturally I'm planning to proceed with the problematic wire removed, but have some concern since it is ostensibly required per the guide. What risks am I taking on by doing so (or rather, what problem may I have had in the first place)?

1652842171897.png


1652842193467.png
 

Stitches

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Don't question it. We take these victories
 

Jmoney

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Haha I see what you mean though am very slightly concerned it could cause a problem later. Or maybe it simply has to do with part variation between these kits. Beyond what I've shown in differences between the guide vs what I'm seeing on the screen, I also noticed this on other areas of the guide such as the PMS looking different and/or having wires present that weren't addressed.
That said, I'll keep moving forward with that orange wire removed and hopefully won't run into any other snags! Thanks for all the replies!

PS since my last screenshot shows the USB failing to load: I am successfully booting RVloader now. The drive was formatted exFAT but changing to FAT32 with 32kb allocation solved that.
 
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