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View topic - Sega Game Gear with flickering screen even after capacitor replacement

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  • Joined: 02 Nov 2019
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Sega Game Gear with flickering screen even after capacitor replacement
Post Posted: Sat Nov 02, 2019 3:58 pm
Hi all,

I would like to ask for your help :)

I have recently bought a few Game Gears and started repairing them, mostly for fun and to learn some things about electronics. On one of them someone else has already made a recap attempt. There were alot of cold joints, 2 missing pads (C49 minus, C39 minus) and another pad that started to lift up (C1 minus). Attempting to turn on the Game Gear did nothing (no power).

As the first step, I have replaced all (electrolyte) capacitors on both the Main and the Sound board. I did my best to workaround the missing pads by running a wire and I have gently pushed back the lifted up pad because I have realized that the trace wasn't broken. After that the Game gear turned on just fine and it could play a game. Even the sound was working. Then I have noticed that the screen is flickering on every brightness level. Not a huge problem but it definitely hurts my eye after a while. Another thing I have noticed that sometimes the screen changes to a lower brightness level for seemingly no reason and returns back to normal after a few seconds.

At first I thought that this issue has something to do with the Power board so I went ahead and replaced all (electrolyte) capacitors there as well. The issue was still present. Then I have swapped out the Power board with a known working one but it made no difference.

I went back to the start and checked whether I have missed something when attempting to workaround the missing pads. By checking things with a multimeter on a working Game Gear, I have noticed that the negative leg of C49 should go to ground however it did not even though I have ran a wire directly to C41. It's still a mystery to me how this could happened but I knew that the negative leg of C35 also goes to ground so I have joined them together with a wire. To my surprise it hasn't fix the issue.

I have also cleared the brightness wheel and resoldered all of its legs.

As a last resort I have replaced the inverter of the backlight and even the fluorescent tube but the issue is still present.

I was thinking about replacing the choke coil and the ceramic capacitor near the inverter but I am starting to have a feeling that blindly replacing components won't get me anywhere and sooner or later I will damage something that I could not replace.

Unfortunately I am not an expert in electronics and I also lack the fault-finding skills so I don't know what should I check next. Any help is much appreciated!
C1.jpg (4.19 MB)
C1
C1.jpg
C39.jpg (2.07 MB)
C39
C39.jpg
C49.jpg (1.59 MB)
C49
C49.jpg
main_board_now.jpg (4.71 MB)
Main board right now
main_board_now.jpg

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  • Joined: 02 Nov 2019
  • Posts: 4
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Post Posted: Sun Nov 03, 2019 3:57 pm
I still couldn't fix the issue however I have a small update on this.

I have opened up the Game Gear and checked the fluorescent tube while it was powered up. It's not flashing so I suppose the problem is somehow connected to the screen itself.

I was surprised by the fact that the brightness wheel doesn't control how bright the fluorescent tube is but rather the "transparency" of the screen.

Maybe something is causing an interference?

By reading the other forums this looks to be a problem with one of the capacitors. If I have to guess then this has something to do with one of the capacitors that had a missing pad. (C49, C39) Maybe connecting the negative leg of C49 to (the negative leg of) C35 wasn't such a good idea or maybe there is a broken trace that I couldn't find.
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  • Joined: 10 Nov 2019
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Same issue
Post Posted: Sun Nov 10, 2019 8:56 pm
Norrecito wrote
I still couldn't fix the issue however I have a small update on this.

I have opened up the Game Gear and checked the fluorescent tube while it was powered up. It's not flashing so I suppose the problem is somehow connected to the screen itself.

I was surprised by the fact that the brightness wheel doesn't control how bright the fluorescent tube is but rather the "transparency" of the screen.

Maybe something is causing an interference?

By reading the other forums this looks to be a problem with one of the capacitors. If I have to guess then this has something to do with one of the capacitors that had a missing pad. (C49, C39) Maybe connecting the negative leg of C49 to (the negative leg of) C35 wasn't such a good idea or maybe there is a broken trace that I couldn't find.


I have same issue,I have recapped 20 or so to date and this is first I have this issue with.

Have swapped out power board with a working recapped one in case of interference,no difference.

Thinking of removing all capacitors I have replaced and swapping with known good caps from another working board In case of a faulty one.

Also clean of brightness pot (will do this first).

Are you making any progress with yours?
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  • Joined: 31 Oct 2007
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  • Location: Estonia, Rapla city
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Post Posted: Mon Nov 11, 2019 7:47 am
There's a non-conducting via somewhere most likely, they will rust out if the recapping and cleanup of the board waits too long, leading to a fairly PITA repair process once it has happened.
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  • Joined: 02 Nov 2019
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Post Posted: Mon Nov 11, 2019 7:53 am
Hello,

Well at least we are having the same problem :)

Unfortunately I haven't made any progress. My father is working as an electric engineer but he rarely got enough time to help me. He however said something like that you can't rule out an interference between the fluorescent tube and the LCD just by swapping out the power board. He suggested to desolder the tube and light the LCD from behind with another light source.

Changing the capacitors again might not be a bad idea though. I haven't tested before soldering them so there might be a small chance that one of them is faulty.

I also recommend that we look for similarities between the two systems:
-What kind of Main board revision do you have?
-Do you also have missing (capacitor) pads on yours?
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Post Posted: Mon Nov 11, 2019 5:32 pm
TmEE wrote
There's a non-conducting via somewhere most likely, they will rust out if the recapping and cleanup of the board waits too long, leading to a fairly PITA repair process once it has happened.


Sounds promising to me! I will make an attempt to check for such VIAs with my multimeter and see whether I can find some issue with one or two.
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