NeoBiosMasta MV1C Problem

Jonap

Mega Shock!!
Joined
Oct 10, 2006
Posts
100
Hi people, i installed correctly the Neobiosmasta mod on my MV1C with Unibios 4.0 ( bios ok ).

But the problem is when i try to start the system dont boot, i see the screen with artifacts and errors, if i remove the mod MV1C works fine again.

What is the problem? maybe the bypass with pin 10 and 21 or bypass with the original bios? im really stuck with this at this point.

MY MOD:
oX3YWT6.jpg


THE ERROR:
KG9s9xB.jpg


Its same like this ( Example MOD working ):
Pasted-into-NeoGeo-Bios-upgrade-1.png
 

avramce

Kabuki Klasher
Joined
Sep 24, 2019
Posts
125
Did you DIY the NBM assembly? When soldering in the PLCC68 socket, there is a tendency for pins to bridge under the plastic of the socket. Flood the contact area with flux and reflow each pad to try to avoid any bridging and try the install again. The fact it is not booting means that the on board BIOS is disabled properly, so the fault lies in your NBM or your Unibios rom.
 

Jonap

Mega Shock!!
Joined
Oct 10, 2006
Posts
100
Did you DIY the NBM assembly? When soldering in the PLCC68 socket, there is a tendency for pins to bridge under the plastic of the socket. Flood the contact area with flux and reflow each pad to try to avoid any bridging and try the install again. The fact it is not booting means that the on board BIOS is disabled properly, so the fault lies in your NBM or your Unibios rom.

its biomasta DIY then, the unibios are OK and the original bios dissable too.

Dont know where i miss, i try 2 biomasta diferents and i flux it all pad when i solder... at first sight seems all pad are fine and not birdged but dont know... maybe i need to buy one of a trusted seller.
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,750
Clean the pins on the CPU. Use a nylon or fiberglass scratch pen.
 

Jonap

Mega Shock!!
Joined
Oct 10, 2006
Posts
100
Clean the pins on the CPU. Use a nylon or fiberglass scratch pen.

Its a good idea, i buy a special pen fiberglass for try this, could be a problem with type of eprom? is 27c1024 with unibios 4.0 free, but i see on old posts MV1C have a diferent pinout for bios and need a 27c400 memory? pin to pin bios for 27c1024 is MV1B only or something like this?
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,750
Its a good idea, i buy a special pen fiberglass for try this, could be a problem with type of eprom? is 27c1024 with unibios 4.0 free, but i see on old posts MV1C have a diferent pinout for bios and need a 27c400 memory? pin to pin bios for 27c1024 is MV1B only or something like this?

With the bios adapter you can only use 1024 or 4002/4096(needs 4x image to fill space).
 

Jonap

Mega Shock!!
Joined
Oct 10, 2006
Posts
100
With the bios adapter you can only use 1024 or 4002/4096(needs 4x image to fill space).

Yes, sorry my fault i want to say 4002, can be this the problem in mi MV1C? because i use 1024 eprom? or with neobiosmasta has no problem of pinout.
 
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