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Maskman

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Hi,

I have a M72 Dragon Breed that doesn’t display sprites at all ! The sound is ok.
Could please help me on this ?

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I could also be interested to a M72 multi. Do you know how much it cost and where to buy it ?

Thanks
Regards
 
I am no tech expert but looks like you have bad sprite RAM try, Piggy backing rams at locations IC21 and IC22
 
I love how people try and play faulty boards.. LOL
Fault find or turn it off to save on damage!!

Anyways looks like you have 2 issues 1 on the tilemap and 1 on the sprites.
The tilemap fault will be the Roms/KNA's/Logic on the bottom board.
What does your ram/rom test say?
 
I love how people try and play faulty boards.. LOL
Fault find or turn it off to save on damage!!

Anyways looks like you have 2 issues 1 on the tilemap and 1 on the sprites.
The tilemap fault will be the Roms/KNA's/Logic on the bottom board.
What does your ram/rom test say?
RAM NG 10, ROM OK !
What about installing a M72 multi ? Don’t know if the kit includes custom IC.
 
You need to get the board fully working before installing any kits.

Ram NG 10 on the m84 is the top board ram (one of 4 2018 ram's)
not sure on location for M72 i'm sure someone will have the list.
 
The Multi kit doesn't include any custom ICs. I can confirm that you will need to get your board working 100% before proceeding with a Multi installation.

These are the four RAM chips on the top board - check them over for physical damage. You may also want to buy replacement chips of the same type and either replace the existing chips or "piggyback" the replacements by setting them on top of the existing chips in such a way that all of the pins line up and make contact.

The culprit may also be one of the 245 series TTL chips since they handle addressing for the MB8421s.

4eYWp.jpg
 
The fujitsu dual ram does MCU stuff, game won't boot if that's faulty so that's ok.
Are the other 2 rams you have circled the work ram? again i think will be ok.
 
The issue should be in the middle board !
Yes and the bottom board for the 'lines in backgound' problem.
Like i said 4 X 6116
Looking at the pics of RT1 it's IC 36,37,38,39
Might be a bad KNA also. :(
 
Hi,

I used the middle board of my "Air Duel", and the RAM OK, ROM OK !!! But stocked on it nothing happen :(

There something to do, like clear the Ram/Rom, something like that ?

Thanks

 
Last edited:
Indeed !!! The game is working now !
issue definitely on the middle board that need components to be checked ! Still these vertical lines.

 
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Do you know how much these RAM cost ?
A tester could detect which ones are defective ? I checked these RAM, but they seem clean (no burnt or bleeding)
 
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