GameBoy DMG-01 isn't loading Games at all

Rufos86 · Oct 19, 2020

Hey all ,

bought a "Not working" DMG - 01 with multiple problems.

the first issue was the leaked batteries that was left in for more than 10 years , I disassembled the Gameboy completely , cleaned all the corrosion , cleaned the shell , put everything back and the Gameboy turn on.

now there was another issue that there was no sound and no picture , I disassemble it again , checked all the traces and found a damaged trace on the DC converter , I fixed it and then there was sound and picture .

so I figured out its about time to check the Gameboy with a game , so as you can guess . its not working , I'm getting the Nintendo logo , the coin sound and that's it , I tried with few different games and I'm getting more or less the same result .

with one game I get the logo on the screen and its there until I turn the Gameboy off .
with other game the logo disappear after loading , and with another game some times I'm getting "something" on screen that looks like its trying to load the game .

also I unsoldered the Game connector , cleaned all the pads , cleaned the connector and re soldered it.

I have 6 different games and I tried with all of them and the result is as above .

I checked all the components for shorts with multimeter , and again all seems to be fine .

can anyone advice ? what else should i check ?

thanks
D

chomel · Oct 19, 2020

I had exactly the same problem. And I did the same you did cleaning every pads... And put some tin on everyone of them. What a pain in the neck... But it worked for me. Maybe you should try to solder another cartirdge connector.
Did you check the continuity to the cartridge connector?

Rufos86 · Oct 19, 2020

chomel said:
I had exactly the same problem. And I did the same you did cleaning every pads... And put some tin on everyone of them. What a pain in the neck... But it worked for me. Maybe you should try to solder another cartirdge connector.
Did you check the continuity to the cartridge connector?

yes I checked almost every component on the board , there was some corrosion on the cartridge connector , so I unsoldered it and put it in white vinegar , then cleaned with IPS and soldered back , checked continuity and all seems good .

the only thing that looked strange to me is that thus 2 pins short , I was sure its faulty capacitor , I removed it , checked the 2 points for continuity and im getting continuity , the Cap is 100Nf and its OK.

is there any thing else that i might be missing ?

--------------------- MERGED ---------------------------

mrgone · Oct 19, 2020

the logo comes from the cart, so it can read lower adresses

Rufos86 · Oct 19, 2020

mrgone said:
the logo comes from the cart, so it can read lower adresses

any idea what should I check ?

also something that I noticed that some times , well almost all the times if turn on the Gameboy without a cartridge I get the black bar logo with holes in it instant of full black bar , i will add picture when i get back home from work

mrgone · Oct 19, 2020

sorry that i am not really helpful, but i suspect that the cart connector needs more cleaning and/or the receptacle

i myself have a game that i have yet to make run on one of my gameboys

Rufos86 · Oct 19, 2020

mrgone said:
sorry that i am not really helpful, but i suspect that the cart connector needs more cleaning and/or the receptacle

i myself have a game that i have yet to make run on one of my gameboys

Thank you, any help is welcome , i will try to clean at again .

Rufos86 · Oct 19, 2020

just a small update

that how it looks sometimes

that one with the cartridge inside

and that's one without cartridge

it looks like there is missing Pixels in the black bar ..... does it mean anything ?

thanks
D

chomel · Oct 19, 2020

mrgone said:
i suspect that the cart connector needs more cleaning and/or the receptacle

I think the same. Or changing wth a new one.

When I say I checek every metal part, I meant that

I tried vnegar but then it corroded again. So I scratched every one of them, then put solder on it, then put back into the connector. And everything worked again. But again it's not a good idea to do that. It's awfully long and painfull. I broke 2 of them, I had to sold the parts with wires. And when each one of them are back in the connector, it's a huge pain to put the connector back into th MB.

Rufos86 · Oct 19, 2020

chomel said:
I think the same. Or changing wth a new one.

When I say I checek every metal part, I meant that
View attachment 229920
I tried vnegar but then it corroded again. So I scratched every one of them, then put solder on it, then put back into the connector. And everything worked again. But again it's not a good idea to do that. It's awfully long and painfull. I broke 2 of them, I had to sold the parts with wires. And when each one of them are back in the connector, it's a huge pain to put the connector back into th MB.

WOW you actually disassembled it to the metal level , its crazy - i guess i'll have to do the same , any advice on how to get the pins out of the connector ? is there an "easy" way to do it ?

Rufos86 · Oct 20, 2020

got a new lead on what might be the problem , at the beginning there was a broken trace on the DC Convertor that i fixed .

i checked the board again and the voltage im getting is really strange , for the 5V im getting it but instant of the negative 19V that i am suppose to get , im getting negative 32 .

i checked the resistor for continuity and there is a short .

the colors are gold black brown that says its 1 ohm resistor , does it makes sense ? can anyone help me to verify the size of the resistor .
i got the schematics but i'm not sure exactly what size it suppose to be

http://www.devrs.com/gb/files/gameboy3.gif

thanks
D

CMDreamer · Oct 20, 2020

As for the resistor value: First band color: Brown = 1 + Second band color: Black = 0. Put them thogether as 10. Now for the third band color: Golden = 0.1 multiplier, so then you have a 1 ohm resistor. And I'm assuming by its (relative) size it is a 1/4th W resistor.

Please, correct me if I'm wrong.

Rufos86 · Oct 20, 2020

thanks, its seems like you are right , its 1 ohm , when i measure it i get 0.2 ohm.

ill have to get a new one replace it and check the negative voltage again.

do you see it in the schematics ? because i can't find 1 ohm resistor anywhere

asper · Oct 21, 2020

Rufos86 said:
just a small update

that how it looks sometimes

View attachment 229894

that one with the cartridge inside

View attachment 229895

and that's one without cartridge

View attachment 229897

it looks like there is missing Pixels in the black bar ..... does it mean anything ?

thanks
D

Probably data reading error; you should have ALL BLACK pixels without a cartridge so it is receiving something which is NOT 0xFF (black) somewhere from the cartridge slot.

In fact, at boot, the bootrom reads 48 bytes from the cartridge (from offset 0x104 to 0x143) which is the Nintendo logo:

and compare them with the bytes stored inside the bootrom itself; if they are not the same the console hangs; without a cartridge inserted those bytes are all 0xFF so you MUST get a black rectangle but you are not receiving it.

After that check the bootrom checks if the sum of bytes form 0x0134 to 0x014C + byte at 0x014D = 00.

If those checks fail the console hangs.

So you probably have a data reading error somewhere in the fist 0x014D bytes of a cartridge (and maybe event after that address).

If contacts are fine and you solve the voltage problem but the problem persists, it can be a fault with LH5264N RAM chip (i don't remember exactly which one of the 2 is the video RAM and which one is the working system RAM but the system RAM should be the one nearer to the cart connector, U3):

If you do not have spare RAM chips try to swap the above 2 and see what happens

Rufos86 · Oct 21, 2020

thanks for the help,
ill try first to change the resistor on the DC convertor and see if there is any change .

what I didn't mentioned is that sometimes I get the full black bar loading logo, although most of the times there is holes in it.

i will try to go over all the soldering points again and reflow them with flux and a bit of fresh solder .

and about swooping the chips , is it really possible ? are they the same ?

Sicklyboy · Oct 21, 2020

Not much to add here from a repair perspective but if needed there are aftermarket PSU/regulator options available if you're not able to resolve the apparent issues with your original one - https://retrosix.co.uk/CleanPower-V2-Game-Boy-Original-p141361110

Rufos86 · Oct 21, 2020

Sicklyboy said:
Not much to add here from a repair perspective but if needed there are aftermarket PSU/regulator options available if you're not able to resolve the apparent issues with your original one - https://retrosix.co.uk/CleanPower-V2-Game-Boy-Original-p141361110

thanks , ill get back home from work, change to shorten resistor with a new one and update.

Rufos86 · Oct 21, 2020

so i changed the Shortened resistor with a new one , now the negative voltage is correct (-19) .

but still it can't load games , reflowed the CPU and the Memory connections and nothing changed .

the black bar logo is missing pixels .

i don't really know what else should i check ......

Bu2d85 · Oct 21, 2020

Rufos86 said:
so i changed the Shortened resistor with a new one , now the negative voltage is correct (-19) .

but still it can't load games , reflowed the CPU and the Memory connections and nothing changed .

the black bar logo is missing pixels .

i don't really know what else should i check ......

It sounds like it’s failing the boot logo check. Maybe something corrupted in the system itself.

This might help you understand what’s happening on a basic level.

asper · Oct 21, 2020

asper said:
Probably data reading error; you should have ALL BLACK pixels without a cartridge so it is receiving something which is NOT 0xFF (black) somewhere from the cartridge slot.

In fact, at boot, the bootrom reads 48 bytes from the cartridge (from offset 0x104 to 0x143) which is the Nintendo logo:

and compare them with the bytes stored inside the bootrom itself; if they are not the same the console hangs; without a cartridge inserted those bytes are all 0xFF so you MUST get a black rectangle but you are not receiving it.

After that check the bootrom checks if the sum of bytes form 0x0134 to 0x014C + byte at 0x014D = 00.

If those checks fail the console hangs.

So you probably have a data reading error somewhere in the fist 0x014D bytes of a cartridge (and maybe event after that address).

If contacts are fine and you solve the voltage problem but the problem persists, it can be a fault with LH5264N RAM chip (i don't remember exactly which one of the 2 is the video RAM and which one is the working system RAM but the system RAM should be the one nearer to the cart connector, U3):

If you do not have spare RAM chips try to swap the above 2 and see what happens

Yes, chips are the same, i doubt both are broken. If this does not work the DMG-CPU internal RAM is probably gone and you need to replace the full chip.

GameBoy DMG-01 isn't loading Games at all

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