Superquinn
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Ireland

I pro-sounded and backlit my DMG, and has been working fine(ish) until recently. There's been some wavering of lcd contrast/led brightness since the beginning (not a regulated power source. Looked that up, found it out.), but now LSDJ is crashing whenever anything processor intensive is going on. (e.g. editing tables during playback, editing chains during playback).
Not only this, but for some reason my backlit DMG can only load the LSDJ cart (EMS) and some of the 'older' games I have. Such as tetris, yoshi, and pac-man. Anything like Link's awakening or pokemon gold/silver just stays in a bootloop.
The carts definetely work, as I have a vanilla DMG which plays them just fine.

Long story short, does the LCD being wired to an unregulated power source have any correlation with game crashing? I need to know before I do any rewiring, as the cables will have to be lengthened and insulated and stuff.

It may be fixable if I just replace the batteries before they get low (as I'm suspecting atm), but that's not a REAL fix.

Anyone know anything about this?

Alley Beach
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clovis CA

LSDJ has been known to crash on labor intensive applications, and is probably best on a GBC or an SP. i cant really see the backlight being a cause for a DMG to crash. maybe change batterys?

herr_prof
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LSDJ should crash very rarely actually on a unmodded, clean slot. Have you an unmodded dmg to test it on to compare the behavior of your songs/cart?

Ive found that some of my store bought mods are very picky when in lower power situations, whats the MAH draw of some of the common backlights versus the stock LED that comes with a dmg?

bitjacker
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Alive and well in fucksville

Power fluctuations can power starve it. This has caused memory in a cart to screw up. without correct resistance, some mods may malfunction.

Superquinn
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Ireland

That's what I was thinking, but It still wouldn't explain why the dmg can only load certain carts and not others. My reasoning is if there's a problem there, then it most likely extends to all other carts but in different degrees. e.g. Tetris works fine, but that may be because it's such a simple game. LSDJ works (mostly) because the cart is made more robust than the original commercial ones (?). I'm thinking that the backlight draws power from the unregulated source and causes a large enough change in current to 'confuse' the processor and the program, throwing it out of sync and crashing it. (I'm going out on a limb there, I don't know much about how the internals work).

And as is the case for the LSDJ program, all that is needed (as you suggest) is just new batteries so the current remains steady. I just doubt that the other carts will have such an easy resolution.

EDIT: I guess my phrasing was a bit off in my first post; my 'vanilla' dmg is my unmodded dmg which i tested the carts on and they work fine. I also tested LSDJ on it and there were no more glitches, so I'm sure that it's a hardware issue rather than a software one. (also thoroughly scrubbed the connectors, so that's been explored too.)

Last edited by Superquinn (Feb 3, 2014 5:03 pm)

Jazzmarazz
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Michigan
Superquinn wrote:

That's what I was thinking, but It still wouldn't explain why the dmg can only load certain carts and not others. My reasoning is if there's a problem there, then it most likely extends to all other carts but in different degrees. e.g. Tetris works fine, but that may be because it's such a simple game. LSDJ works (mostly) because the cart is made more robust than the original commercial ones (?). I'm thinking that the backlight draws power from the unregulated source and causes a large enough change in current to 'confuse' the processor and the program, throwing it out of sync and crashing it. (I'm going out on a limb there, I don't know much about how the internals work).

That is basically correct. Certain opcodes do require more power, especially related to the sound. This can easily cause it to crash if you're starting out with less!

Which "unregulated power source" are you connecting it to? The battery terminals!? The best places are for you to connect it to the capacitor below the screen or to the power LED voltage, prior to the resistor of course. These are both regulated power sources. You should not have to lengthen the wire.

Superquinn
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Ireland

That's where they're connected. To the power source directly below the screen  (the leg of what I assume is the capacitor you're referencing), and the ground directly to the right of the screen. The two cables basically reaching for the nearest spots possible from under the cable that sends the vertical data to the lcd.

Hmn. I always assumed that the only regulated source was from that one point on the left of the main board. opposite side from the prosound connection points. Heh, shows how much I know!

Last edited by Superquinn (Feb 3, 2014 5:35 pm)

Jazzmarazz
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Michigan

The mainboard pin is the very closest point to said regulated source, but there are filter capacitors throughout, so it is all regulated as far as I am concerned. Is this a backlight with a built in resitor, or external? It may be a good idea to increase the resistance value. It may also be a good idea to replace some of the electrolytic caps as well. What CPU version is in there? I am not so much concerned with the CPU itself, but the revision of the power regulator in the bottom corner; the older ones are not as good as the newer ones which contained much larger caps.

Superquinn
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Ireland

It's from 1990, if I recall correctly. (it's what was printed on the back of the LCD board). I had been noticing that a corner of the gameboy was warmer than other parts, but it was subtle enough that I always assumed it was just the warmth from the palm of my hand. (the pointed bottom corner, opposite the speaker.) My other dmg is '91, so i could just unsolder the prosound cables from this one and move the whole front screen -cover and all- and stick it on the base of the 'newer' one. Switch halves, basically. Would a year's difference matter?

As for the backlight, I'm using nonfinite's v5 backlight. There's no tutorial at present for that model, but it seemed straightforward enough to install.
I'll try for a resistor as you suggest. I have 220, 1k, and 10k. The page for the v5 says the resistor is already installed though.

Last edited by Superquinn (Feb 3, 2014 6:20 pm)

sxe_weekend
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Litebritedeath Land

I had this Happen with a pocket.  Games worked fine in it but LSDJ caused dimming and crashing.  All I had to do was solder a resistor in and it's worked like a charm ever since.

Jazzmarazz
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Michigan
Superquinn wrote:

It's from 1990, if I recall correctly. (it's what was printed on the back of the LCD board). I had been noticing that a corner of the gameboy was warmer than other parts, but it was subtle enough that I always assumed it was just the warmth from the palm of my hand. (the pointed bottom corner, opposite the speaker.) My other dmg is '91, so i could just unsolder the prosound cables from this one and move the whole front screen -cover and all- and stick it on the base of the 'newer' one. Switch halves, basically. Would a year's difference matter?

As for the backlight, I'm using nonfinite's v5 backlight. There's no tutorial at present for that model, but it seemed straightforward enough to install.
I'll try for a resistor as you suggest. I have 220, 1k, and 10k. The page for the v5 says the resistor is already installed though.

Try adding the 220 to one of the wires. It will be a little more dim, but this is my suspicion as to the crashing.

sxe_weekend wrote:

I had this Happen with a pocket.  Games worked fine in it but LSDJ caused dimming and crashing.  All I had to do was solder a resistor in and it's worked like a charm ever since.

In this case, I doubt it was the software. It was most certainly the cartridge. What cart was LSDj playing from?

12ianma
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power draw etc should not really crash the software. I ran a thrash city save on a cart in a dmg and it didnt crash a fully modded dmg. It was however bogged down quite a bit. I was testing differences between performance of sgb vs dmg cpu

Superquinn
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Ireland

Heating up the iron as I type. Thanks!

Will update with outcome in a bit!

Last edited by Superquinn (Feb 3, 2014 7:03 pm)

Jazzmarazz
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Michigan
12ianma wrote:

power draw etc should not really crash the software.

Power draw can most certainly crash the software of any system. How can you begin to claim otherwise?

12ianma
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you can run a bunch before power draw issues arise even off of standard dmg reg board. You ever seen Nex's megatron?

Jazzmarazz
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Michigan
12ianma wrote:

you can run a bunch before power draw issues arise even off of standard dmg reg board. You ever seen Nex's megatron?

Run a bunch of what? You keep saying things like "bunch" and "fully-modded" but these phrases mean nothing at all. There is no threshold of LEDs or knobs that once achieved warrants something as "fully-" anything, pal.

Yeah, I have seen it. There are only two things drawing power that weren't in the original regulator calculations! The only thing the damn thing has that is special is the size. 6 LEDs, an LTC and a Atmel328. None of the other mods draw any power; not the dual pro sound, not the expanded cart slot and he never did share a video of the powering a keyboard while the LTC ran and the arduinoBoy was powered up.

Besides, he used a clear gameboy which indefinitely had the newest power regulator board with the largest capacitors and lowest bleeder voltage. Combined with proper resistance values on the LEDs and power connections to the LTC and Atmel which are designed to draw a static value of power, NeX has nothing to worry about.

Your basically saying that I can build a computer with quad SLI GPU's and pop in a 150W PSU and run with it.

If SuperQuinn has a gameboy with dried up caps, failing resistors and continues to add more load on the regulator, then yes the software will be affected.