Hardware Problem with GBA SP motherboards

[Deleted User]

Hello,

I've got a really hard day today, because of my two MBs from GBAs SPs. I bought a broken AGS101 for a screen swapping into classic GBA. The MB was in a great condition and fully working. Because I was needing a new LCD I've bought second frontlight SP. The screen was working with both of my MBs.
There was a problem with R button in my new MB. I thought that R button is dirty or damaged. So, I removed it clean it and solder it back, but it does not work.
So, I desolder the chip from my first MB (it is a chip for ags 001 to ags 101 I think??), but the LCD is not working after it as you can see in the picture. I realized that I did a big mistake. After resoldering the chip back the LCD is not working anymore. Anyway, I removed an R button from my first MB and solder it into second one. The problem is the same - it is not working.
I tried to meassure the contacts and I realized what I post in the pictures. In the second MB there is not connection with one pin-hole of the R button. There is a connection on both in a first MB and working.

So, in a conclusion:
First MB
-everything works great, LCD connector is maybe damaged, but why? Conversion chip should not do that.
Second MB
-LCD is working, everything works except R button, because of rust maybe

What to do with that? Thank you.

1. pic working LCD with second MB
2. pic second MB - close up with desc
3. pic second MB - close up
4. pic not working LCD with first MB
5. pic the point I desolder from first MB, it was in the first pin of the connector
6. the conversion chip on a first MB

BTW: sorry for my english

 

[FAST6191]

Why the bubble wrap?

Anyway 4.jpg seems to show vertical lines on the screen randomly so the immediate thought there is bad connection. I don't know if it is just the angle but the backlight also seems to be out compared to the other shot. What happens if you wiggle the ribbon or put a bit of pressure on top of the connector?

5.jpg
One of the pads there appears to be ripped off for the R button. Though looking at https://gbhwdb.gekkio.fi/consoles/ags/ then that was just a shield anchor point. Also is it the first one which it works on?

Anyway can we get some photos of the underside of the second board with a bad R button? The broken bit on top is not idea, and if something got under the mask then it can creep along and break things further down the line but nothing on the bit we can see should interfere.

 

[Deleted User]

Hey FAST, thank you for your reply

I usually use bubble wrap for shell replacement to avoid scratching while moving on a table.

MB1:
While moving the connector it makes randomly lines. Sometimes only half of the screen appears. Sometimes it is just a blank screen without Gameboy Advance words. Sometimes red lines, etc... I can not find the right position for it, but as you can see LCD is working. Yes, after I disoldered (if this is the right word for opposite of soldering) the conversion chip from a LCD female connector (5.jpg) the light is not working anymore. If I solder it back it is a normal. Maybe - Should I disolder every cable of that chip from another points of MB? Not just that from LCD connector. I think it is just a normal frontlight MB with the conversion chip.

Also MB1:
Yes, that's true, there is a missing one pads (position - top, right), but it was just for holding a microswitch on the board. Signal line is in a good condition. In the fifth photo - 5.jpg (that MB with a missing pad), there is a first and fully working MB without R button which I removed for the second one.

MB2:
I posted the pictures of both MBs. You can clearly see what image corresponds to description.

I copy it again:
1.jpg - working LCD with second MB (not working R button)
2.jpg - second MB - close up with description of what I found out
3.jpg - second MB
4.jpg - not working LCD with first MB (R button working, there is a missing pad, but it works - it only holds a switch)
5.jpg - the point I desolder from first MB, it was in the first pin of the female LCD connector (only one point desoldered)
6.jpg - the conversion chip on a first MB (should I remove it permanently?)

I wanted to posted a video of a LCD screen with first MB, but it is not possible in this forum.

 

[Deleted User]

Hello, if anyone is wondering. I've repaired both motherboards successfully
There was a problem with the first one with that chip used to change 001 MB to 101 MB. Some of you know it is necessary to break a electric line going from first pin of screen socket. I've removed the chip from MB and then repaired that track. It is tricky, but with the right tools it's easy to repair. You have to scratch both ends of broken electric line and then solder one wire of a copper cable. Easy - the frontlight is now working.
There was also problem with screen socket. Removing it was easy and everyone could do that with basic soldering skills. But on the other hand it is really hard to solder a new socket into MB. You need a eagle eye and very thin tip on soldering station. I did not use a microscope and it took me few hours to finished it.
All done - the first MB is in a great condition.

On the second MB there was a damaged condensator from the other side of MB, the repair was simply - solder it to the board even if it has only 2mm. Anyway, I think it was not the reason why R button was not working. I used my first repaired MB as a comparison and try to figure out what's going on in it. Unfortunately there is not a schematic of the GBA SP motherboard, so I start to find the issue with a multimeter. The problem was that from test point of R button it was not connection in a CPU. It wasn't because the hole which is istuated left from A button (there is number "1" next to the hole) was dirty and there was no connection with the hole which goes to other side of MB. I use a thin copper wire and solder it - again, it is working now.

Without the right images it is hard to describe it, but I am too lazy Anyway, if some of you would have the same problem, then I try to explain it more with pictures, of course.