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  • Joined: 02 Nov 2019
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Recapped Game Gear does not boot games, glitched TMSS
Post Posted: Sat Sep 12, 2020 12:48 pm
Hi all,

TL;DR;
I have re-capped Game Gear did not boots into games and now has a glitched license screen at start and I would really like to know what is the problem.

A few day ago I bought a faulty Game Gear hoping that I could fix it. There was battery leak in the left battery holder and the previous person did a terrible re-cap attempt (cold solder joints everywhere, some of the capacitors already fell off). It was a VA1 (Europe). Both pads of C55 were missing but everything else seemed to be in good shape on the motherboard. I connected the negative leg of C55 into R45 and the positive leg to the farthest leg of Q9. I also made a jumper wire from Q8 to the positive leg of C55. The rest of the re-cap was straightforward. Once I turned on the Game Gear with a game, it come up with a white screen and the contrast wheel was also working. I thought that my job (with the motherboard) was done but when I put in a game, it never passed the license screen ("Produced by or under license from Sega Enterprises LTD.") even after I cleaned the game with isopropyl alcohol and re-inserted it a bunch of times. (I have tested multiple games.) I have never seen this issue before.

I have checked the board for corrosion thinking that the battery leak might has caused some problem but the only thing I found was something that looked like flux residue between the legs of IC3. (MB8464A-10L) I have cleaned it and resoldered each leg anyway. I have also checked for broken traces in this area but found none.

My next idea was that there might be a cold solder joint for one of the legs of the cartridge connector. I have checked each leg and found nothing on the visual inspection. I have reflowed each leg just to be sure and this is where things went from bad to worse. The license screen was still showing up as before but now it was glitched. I have reflowed each leg again but nothing changed. Another wierd thing I noticed is sometimes when I turn the Game Gear on without any game in it, the license screen still appears but the text is much smaller. Like when you are playing Master System games though a Master Gear Converter on your Game Gear.

I was a little desparate at this point and used sandpaper to "clean" the cartridge connector but it did not help. I also looked for bent pins inside the cartridge connector but as far I can see, all of them are alright. (I only have a cheap chinese USB microscope and looking into the cartridge connector is not an easy task so I would not bet my live on it)

My final idea was that I might have screwed up the cartridge connector somehow (I feel stupid) so maybe I could just replace it with another one from one of the dead Game Gears I have. I only have VA0 (Europe) Game Gears for spares but the cartridge connector looked like it might fit however once I desoldered all of the legs I have realized that it is also fixed with rivets to the motherboard so removing it is not that easy.

I'm kind of clueless about what I should do next. I really appreciate any help you can provide.
20200912_111047.jpg (1.1 MB)
glitched license screen
20200912_111047.jpg
20200912_111324.jpg (846.82 KB)
glitched license screen small
20200912_111324.jpg
20200912_111740.jpg (1023.08 KB)
motherboard
20200912_111740.jpg

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Recapped Game Gear does not boot games, glitched TMSS
Post Posted: Sat Sep 12, 2020 7:40 pm
This is exactly the same issue I was having before screwing with the cartridge connector:
https://www.reddit.com/r/consolerepair/comments/9i5j51/sega_game_gear_no_games_l...

The Game Gear now shows a glitched license screen (or TMSS screen if you will) and starts in Master System mode even without any game inserted which is weird.

I don't own a working Game Gear with TMSS but I am assuming that it should come up with a white screen when turned on without a game.

I am wondering what could make it think that there is a game inserted that requires Master System mode. The pins in the cartridge slot don't look bent or anything.

It would be great to replace the cartridge connector so I can narrow down the issue...but those rivets seem risky to remove.
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Recapped Game Gear does not boot games, glitched TMSS
Post Posted: Mon Sep 14, 2020 4:53 pm
I could not solve the issue but I am amazed by how much useful information SMS Power has! :)

I have found the pinout and a nice discussion about how the Game Gear known whether it should run in SMS mode when started. The value that determines the mode is read from pin 42 and there is a pull-up resistor connected so as far as I can understand it defaults to 1 which means it starts up in SMS mode when no cartridge is inserted. Really interesting stuff but this one is a dead end :) I now know that in theory, the SMS mode is the default.

What is surprising however is that according to the same discussion, the Game Gear should not show the license screen (or bumper screen) unless there is a cartridge inserted because of a second check that is also done by the BIOS. (so you should never see that license screen in SMS mode without a cartridge) My Game Gear shows a glitched license screen in SMS mode with no cartridge inserted.

I have checked all legs of the cartridge connector for solder bridges but there is none. I went through all of them with the multimeter anyway with and without a cartridge inserted but everything seems to be okay there.

I am little confused now...could the BIOS go corrupt for some reason? :) Which chip houses the BIOS? Maybe I can check the traces there and reflow each leg of that chip.
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Post Posted: Mon Sep 14, 2020 5:25 pm
The BIOS itself is very resilient - literally etched in silicon. My guess is that you have a bad connection between the video chip and video memory.
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Recapped Game Gear does not boot games, glitched TMSS
Post Posted: Mon Sep 14, 2020 8:09 pm
Maxim wrote
The BIOS itself is very resilient - literally etched in silicon. My guess is that you have a bad connection between the video chip and video memory.


That sounds like a good idea :)

I have checked the service manual for the VA1 Game Gear and it seems to me that IC1 (the huge ASIC) contains the video chip and IC2 looks to be the video memory.

By looking at the block diagram it seems like there is only 3 connections between the two chips and I have never checked those before. I can verify them tomorrow hopefully. Thank you!
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Post Posted: Mon Sep 14, 2020 11:29 pm
I think there’s at least 17 connections...
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Recapped Game Gear does not boot games, glitched TMSS
Post Posted: Tue Sep 15, 2020 7:02 am
Well at least I got, the two ICs right :)

I will try to verify each connection and report back with my findings.
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Post Posted: Tue Sep 15, 2020 3:53 pm
I did a quick scan with the multimeter and all legs of IC2 seems to be directly or indirectly connected to IC1.

Could a connection be bad even when there is continuity?

I am thinking about reflowing all legs of both chips using my cheap microscope.
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Post Posted: Thu Sep 17, 2020 3:22 pm
Alright, now I am getting somewhere :)

I have reflowed all legs of both IC1 and IC2 but it didn't change a thing.

After that I got an idea that maybe the remains of cold solder joints are still around the motherboard and connecting something that should not be connected. (The Game Gear already had a recap attempt before it got to me and some capacitors fell off because of the cold solder joints)

I don't have any compressed air however I do have a trusty compressor in the garage so I used that one to get rid of debris that might be left in the motherboard.

To me surprise, the Game Gear no longer displayed the glitched license screen when turned on without a game, it showed a simple white screen.

I can now get a perfectly fine Game Gear license screen most of the time when I insert a game however it either goes to a white screen or a screen of solid red or blue. That is, it never boots the game. I guess I am back to problem one.

Maybe the cartridge slot is dirty after all or could this be a connection problem as well?
20200917_165029.jpg (3.28 MB)
Correct license screen
20200917_165029.jpg

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Post Posted: Fri Sep 18, 2020 9:59 am
I have cleaned the cartridge slot as best as I could but the problem still persists.

There is another thing that I have noticed that might worth mentioning. If I leave the Game Gear turned off for 30 second and turn it on again without a cartridge inserted, it will show a glitched TMSS screen in Master System mode. If I turn it off and turn on immediately, it will show a white screen just as it should. I could reproduce this problem every time when I wait 30 seconds before turning the Game Gear on.

Hmm..I am wondering what are the odds that either of the RAM chips (IC2, IC3) went bad? According to the service manual of VA1, it has the same RAM chips as the VA0 and I have plenty of faulty VA0 Game Gears at home. I could maybe replace them. Would it worth a try? :)
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Post Posted: Fri Sep 18, 2020 1:35 pm
Norrecito wrote
If I leave the Game Gear turned off for 30 second and turn it on again without a cartridge inserted, it will show a glitched TMSS screen in Master System mode.


maybe a short on the master system mode pin when some component is cold?
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Post Posted: Fri Sep 18, 2020 6:07 pm
sverx wrote
maybe a short on the master system mode pin when some component is cold?


I wish it would be that simple :(

I have checked the pins and the legs of the cartridge slot multiple times with a multimeter but haven't found any shorts. I have also cleaned up any flux nearby.

I have very limited knowledge when it comes to the Game Gear but according to the discussions I have found on SMS power, the Master System mode is the default so this one is not surprising but everything else is just weird:

Why does the Game Gear think there is a game inserted? (It should only show this screen when it has detected a game)
Why is the screen glitched?

I also did a proper recap of the sound board and now I hear some static when the TMSS screen fades. At least I know that the sound board is probably okay now :)
20200918_113853.jpg (669.59 KB)
glitched tmss
20200918_113853.jpg

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Post Posted: Sat Sep 19, 2020 3:50 am
FIXED!!! :)

It was a broken trace between the cartridge slot and IC1.

The Game Gear VA1 service guide has a diagram that shows how the data and address pins of the cartridge slot are connected to IC1. I have started checking each connection with the multimeter and found that the trace between pin 29 (address 11) and IC1 is broken. After soldering in a wire, the Game Gear works perfectly.

Very interesting, I hope my findings could help out someone else in the future :)
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Post Posted: Sat Mar 13, 2021 4:31 pm
Norrecito wrote
FIXED!!! :)

It was a broken trace between the cartridge slot and IC1.

The Game Gear VA1 service guide has a diagram that shows how the data and address pins of the cartridge slot are connected to IC1. I have started checking each connection with the multimeter and found that the trace between pin 29 (address 11) and IC1 is broken. After soldering in a wire, the Game Gear works perfectly.

Very interesting, I hope my findings could help out someone else in the future :)


hello, i'm having the same exact situation.
Stuck in a tmms boot screen,... First time ver happened This when fixxing a game gear..

So, the problem was a bad connection bettwen One of the pins of the cartridge and the IC1..
Fuck, they're really small traces...

Do you have the sheamatics?

Is there not a simplier way like to ground or not a pin on the cartridge slot to tell os a gamegear game or not?

Just to check ..
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Tmss game gear
Post Posted: Sat Mar 13, 2021 7:45 pm
Hmm

The 42 cartridge pin is GG mode (0) or SMS mode.(1).
It.conects to pin 38 of.ic1..and as a 4.7ohm resistor to 5v..

So. What i'm missing here? If the IC gets 5v is a.sms.game. if.is.a.gg game.gets.0v ..is that.it?

Any ideas how to check and fix This situation

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Tmss game gear
Post Posted: Sun Mar 14, 2021 12:33 pm
I dos só e reflowing in the cartridge conector..
Put a game in..

Went to teste pin 42 of the cartridge and its 0v. Its correct.

Pin42(0v) ---- r23(4.7ohm)--- 5v..
|
|
Pin 38 IC1


Everything checks out..


Tried to bypass BIOS, and put some solder on J1. The BIOS is bypassed, but the games just dont start....

Dont know what to do Next..
The game gear works, the games are wotking, the BIOS screen os shown but the games dont start
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Recapped Game Gear does not boot games, glitched TMSS
Post Posted: Sun Mar 14, 2021 1:45 pm
I would start by checking the continuity of each Address lines (A0 - A15) between the cart slot and CPU (IC1) using a multimeter and the schematic.

Also check that there are no shorts between the each of the Address and the other Address lines, e.g. No continuity between A0 and A1, or A0 and A2, and so on.
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Tmss game gear
Post Posted: Mon Mar 15, 2021 9:45 pm
I have checked all connections bettwen the cartridge connector and the IC1..

All gives signal but one. Numbers 4 A12. Trace it with the scheamatics and verified that it conects to ic3 pin 2.. so i install a Wire and now i have signal on ic1 pin 14..

I was felling really confident that This das going to solve This issue..

But no.. the damm problem continues..
Damm it..
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Tmss game gear
Post Posted: Wed Mar 17, 2021 12:19 am
Well...

Something diferent now.

It just males BIOS screens rest loops... What about that..
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Post Posted: Wed Mar 17, 2021 10:43 am
a short that resets the Game Gear as soon as the cartridge gets enabled?
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Post Posted: Sat Mar 20, 2021 12:42 am
sverx wrote
a short that resets the Game Gear as soon as the cartridge gets enabled?


Yes..power on. shows the bios screen..and instead of booting the game, just makes infinit restarts to bios screen...

TMSS screnn loop over and over again..
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