GBA SP won't read some Game Boy / Color games--help me fix it? (internal switch issue)

[Jesse_Dylan]

(Feel free to skip down to the "What I think is wrong" section! That is the only crucial info.)

Hi! Hope you guys can help! First, a story about me (you can skip this part if you want). I got a Game Boy right when it was released in 1989, and it became a huge part of my childhood, including the Game Boy Pocket, Game Boy Color, Game Boy Advance... Sadly, like so many, I lost, sold, traded, liquidated all my Game Boy systems and games. I have spent about a year now repurchasing them all, used--a Game Boy, a Game Boy Pocket, two (!) Game Boy Colors, a Game Boy Advance, a GBA SP with front light, a GBA SP with backlight, and a Game Boy Micro. Whoa! I've gotten a lot of the old games I loved, too. I will never recover my entire childhood collection, and don't want to, but in particular I've gotten back a lot of the RPGs I loved to play, and some I never got to play.
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(Feel free to skip the above!)

Here's the deal. My backlit Game Boy Advance SP does not reliably play Game Boy or Game Boy Color games anymore (which sucks, as that was the main thing I bought it for). It plays GBA games just fine, and many Game Boy and Game Boy Color games are fine, too. One that does not work in it is Dragon Warrior 3, kind of all Game Boy Color games. However, this same DW3 works just fine in both Game Boy Colors and all the other Game Boy Advance systems.

One thing I've tried is taking the board out of the DW3 case and putting it into the case from a different game that does work (Mario Golf). This should theoretically solve the problem, but it didn't. I could try another case, or maybe even a Game Boy case (rather than Game Boy Color) and see if that fits, although I don't know if there is risk involved there. I don't want to do anything to damage DW3 or my Game Boy!

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(What I think is wrong)

I think that all Game Boy Advance systems have a "toggle" switch inside them. When a Game Boy Advance cart is put in, or when there is no cart at all, this switch is left "neutral," which keeps it in GBA mode. However, when a Game Boy or Game Boy Color cart is inserted, the switch is meant to be pushed, putting it into Game Boy Color mode. I think that some carts are not properly keeping this switch pushed, so the switch gets unpushed within the first few seconds and sends it back into GBA mode, thereby locking up the system.

Really long story short, how can I fix this switch?? It could be the switch itself, a game (or several) with case dents in a crucial spot, or it could even be that the actual system casing has gotten loose and so it's not tight enough in there to hit the switch (uh, that's what she said). I have tried tightening the screws, but I have not taken my system apart. I have never taken any game system apart before. I can take the carts apart, but they are simple beasts.
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Any insight would be appreciated, and I'm sorry for all the jabber!

[Tanooki]

Between the 3 versions of gameboy (GB, GBC, and GBA) there were ways for that to work. Between the GB and the GBC what they did was for unique GBC games they didn't have that power switch notch taken out of the top right corner of the cart, that's how it would know to GBC complete mode, or GB/GBC hybrid mode.

On the GBA though it's another form of trigger, a soft switch of sorts on a spring down by the cart pin slot in the bottom. On the GBA there are those notches out of the back of the cart down by the pins on both sides, the GB/GBC stuff lack this. So when the GB/C stuff goes in, it shoves that switch down which is normally up so it disables GBA mode. I'd check and see how that switch looks outside. If it's recoiling and popping up fine, something is wrong inside and you'll need to see if some sensor pad(if that exists like for buttons) or a little wire or trace is blown and fix it.

[Jesse_Dylan]

I'll have to figure out what the switch looks like in there.

One thing I did was swap DW3 (GBC) and Final Fantasy Legend II (Game Boy). I just opened both carts and swapped the boards. It's working totally fine now, "disguised" physically as FFL2. I don't know if certain carts just don't push it down correctly or what! Tetris Plus, which is an original GB cart like FFL2, was giving problems as well.

I guess it is something wrong with that switch in the GBA SP, but it is not wrong enough that it affects every game, only certain games that have a certain cart "defect", if that's the right word...

[Tanooki]

Maybe some dust or junk got into the switch so it's not going all the way if that sneaky trick worked. Seriously though, I question why seeing that you triggered a GB mode on a GBC only game, that's odd.

It's not hard to see. Imagine looking down the slot with the back of the game that goes in there side being closer to you and label out. The little switch is on the right just off to the side (sticking out from the side, not top/bottom) from the pin connector.

[SparTonberry]

Between the 3 versions of gameboy (GB, GBC, and GBA) there were ways for that to work. Between the GB and the GBC what they did was for unique GBC games they didn't have that power switch notch taken out of the top right corner of the cart, that's how it would know to GBC complete mode, or GB/GBC hybrid mode.
All the notch/lack of does is control whether the power can be turned on on an original model (DMG-001) GB. It doesn't affect GB Pocket or Super Game Boy.
Games themselves would have to detect what system they are on through software. How it was done was that the boot ROM inside the GB (the one that displays the Nintendo logo and (attempts to) check if it's a licensed cart) writes a value to the hardware register that cloaks that boot ROM and enables the cart. While technically it just needed to be a non-zero value, Nintendo used different values to signal the hardware version, so once the cart ROM gets control it can read that immediately to know which console it's on.
So GBC-only games still needed to have an error warning screen for GBP/SGB since the game could still be booted on those.

[Tanooki]

I'm speculating a bit considering what he said about moving the game board from one shell to another and then it worked. If you got a better idea I'm curious what it would be.

[BlastProcessing402]

I'm speculating a bit considering what he said about moving the game board from one shell to another and then it worked. If you got a better idea I'm curious what it would be.

Your idea about the power notch is just wrong, though. The power switch notch does nothing at all on anything but the original Gameboy. There's literally nothing near that notch that could detect it. On an SP, the notch is like an inch away from the system.

Even on an original GB it's just a physical thing, mainly meant to keep you from pulling carts out while the system is on, similar to how the SNES was until they redesigned the cart casing. I think the original Japanese Megadrive had a similar lock, left off when they made the Genesis.

However, you are right in that there is a voltage switch in the slot of a GBA that is pressed by GB/C games, which is how that's detected. I doubt it's what's causing problems with his GB/C games, though. If it was stuck depressed, this would make GBA games not work. If it's stuck up, he wouldn't be able to get GB/C games in at all.

I wonder if there's some sort of damage to the cases of his non-working GB/C games, that have worn away the side so it fits similarly to a GBA game without triggering the switch.

[SparTonberry]

I think the original Japanese Megadrive had a similar lock, left off when they made the Genesis.
That also doubled as a region-lock, except unlike the SNES it was harder to remove without visible damage to the console case.
(well, that notch would stop a western game from fitting in a JP MD. However, it was the round edges of a Japanese cart that would stop it from fitting in a western console.)
Though it's less of an issue since you pretty much need an import adapter or a Game Genie (plus codes) for many of the later games which used software-based region lockout.

[Tanooki]

I ran out of ideas and I dn't have a torn open set of gameboys or specs here to figure it out so I was guessing as it's just too weird. The fact the wrong game worked in the wrong case, and the right game failed in the right case is too odd.

[Jesse_Dylan]

Hey guys!

Sorry for my slow reply.

OKay, here is my understanding, as best I can describe it. Regular Game Boy games are just that, Game Boy games, and they will run on any game boy into which they fit. However, games designed to have a special Game Boy Color mode (black carts) have two partitions basically. Only Game Boy Colors (and Advances) can access that special Color portion. So they'll run in any Game Boy, and a Color or Advance will detect that extra partition (or whatever).

However, even GBC-only games still have a Game Boy partition! I confirmed this.

Basically, I took an original Game Boy game and a GBC-only game. I took them apart and moved the GBC board into the GB shell and the GB board into the Color shell. This won't effect the original GB board, except that the cart itself will not fit physically into a non-Color or non-Advance Game Boy!

However, now the GBC-only board WILL FIT into any Game Boy, because it's physically in an original Game Boy shell. So, in a Game Boy Color or Advance, it is recognized, and the Color Only portion is used. Put it into an old, original Game Boy, or Game Boy Pocket, and it only accesses the portion that is for Game Boy only, which results in a greyscale 4-color screen that says "Dragon Warrior III is for Game Boy Color only".

I hope this makes sense. That's how the locking works in the software. On the hardware side, the different shells have different notches and stuff which can physically keep a GBC cart out of an old Game Boy, but if you could get it in anyway (I'm sure there are ways), it would just show the screen saying it won't work on an original Game Boy.

To complicate matters, the Game Boy Advance and GBA SP have special physical switches that toggle Game Boy Color mode. Anytime a Game Boy or Game Boy Color cart is in a GBA or GBA SP, it should flip a switch to turn on GBC mode. If the cart is slightly dented in the wrong spot, or if your physical switch inside your GBA or GBA SP is a little goofy, it might not toggle, and it might try to run in GBA mode instead, which will lock it up, or it might switch in mid-game, which also locks it up.

I guess my DWIII cart just had an issue, as perhaps does my GBA SP. Switching it to the regular GB shell maybe has less issues. It recognizes it as Game Boy (because it flips the switch), boots to Game Boy Color mode, and reads the Game Boy Color portion because the chip in the GBA and GBA SP is a Game Boy Color chip and always works like a Game Boy Color, regardless of whether it's a GB cart, GBC/GB hybrid, or GBC-only cart (which is also a hybrid, as I discussed above, but the GB content is limited to the "will not work" screen).

Hope all this makes sense.

[goldenband]

From what I remember you can get some fun messages when booting a GBC game in a monochrome GB. IIRC, a few games have special screens with animations. Some games simply don't work, others try to run.

[theclaw]

Hey guys!

Sorry for my slow reply.

OKay, here is my understanding, as best I can describe it. Regular Game Boy games are just that, Game Boy games, and they will run on any game boy into which they fit. However, games designed to have a special Game Boy Color mode (black carts) have two partitions basically. Only Game Boy Colors (and Advances) can access that special Color portion. So they'll run in any Game Boy, and a Color or Advance will detect that extra partition (or whatever).

However, even GBC-only games still have a Game Boy partition! I confirmed this.

Basically, I took an original Game Boy game and a GBC-only game. I took them apart and moved the GBC board into the GB shell and the GB board into the Color shell. This won't effect the original GB board, except that the cart itself will not fit physically into a non-Color or non-Advance Game Boy!

However, now the GBC-only board WILL FIT into any Game Boy, because it's physically in an original Game Boy shell. So, in a Game Boy Color or Advance, it is recognized, and the Color Only portion is used. Put it into an old, original Game Boy, or Game Boy Pocket, and it only accesses the portion that is for Game Boy only, which results in a greyscale 4-color screen that says "Dragon Warrior III is for Game Boy Color only".

I hope this makes sense. That's how the locking works in the software. On the hardware side, the different shells have different notches and stuff which can physically keep a GBC cart out of an old Game Boy, but if you could get it in anyway (I'm sure there are ways), it would just show the screen saying it won't work on an original Game Boy.

Just the original Game Boy. GBC-only games lack a physical means to block Game Boy Pocket, Super Game Boy, and Game Boy Light.

[SparTonberry]

And it's not really a partition, more like dual-compatible games GBC games have graphics-handling code that's like
if SYSTEM = GBC THEN DoColorGraphicsStuff
ELSE DoMonoGraphicsStuff
Possibly they'd also store separate graphics for GBC and GB modes

[Tanooki]

That's right, and the hybrid games don't do extra stuff if I recall right. They just store one set of data both systems use, but then there's colorization code put into the hybrid carts so when the game sees the GBC system it'll use that instead. It's much like the Super gameboy junk on that cartridge, same game, just stored color coding but the same tiles (though SGB games did store the added border and in a few cases digitized audio the SNES would play.)

It was the GBA where you'd have added data thrown on a GBC game so you'd get extra areas (color dungeon Zelda DX), added colors over the GBC which Dragon Warrioe 3 does.