MVS noob calls for aid - making a Neo Diagnostics Bios Z80 test cart (m1.bin)

[hatmoose]

Hi Team

I've just started on my MVS adventure with the cheapest MVS on the market (aliexpress MV1-FZ) and a bunch of bootleg carts.They have very diligently carved "china warning sale" into the MVS shroud, it's not just painted on, it's actualy gouged into the plastic. All of the carts that I will be using for this are horribly-executed non-functional bootlegs. No hardware of any interest to collectors will be damaged in any way.


The universe bios seems straightforward enough, I can manage a 27c1024

I'd also like to use the test bios and the z80 test software from here
http://smkdan.eludevisibility.org/neo/diag/

The test bios (sp1.bin) is also OK, another 27c1204 - but i'm absolutely stumped by the z80 test (m1.bin)
The CHAR boards I have are 42G-1 which use a NEO-ZMC so in theory they should work finw with the z80 test code


What I need to know please is; what kind of chip do I burn the m1.bin code onto so I can install it in the 42G-1?
I'm such an MVS moron that I dont even know what chips go onto a CHAR board...

Has anyone done this? Any thoughts, or suggestions would be hugely appreciated

 

[stj]

the sound rom replaces the M1 chip on the left - with "MX" on it.
what part number is that? it looks like a flash chip - which would be handy for you.

btw, how cheap are the games on aliexpress?
i was going to make a test cart but didnt want to wreck what i have.

 

[hatmoose]

OK so m1.bin goes in the hole marked "M1" on the board - yup, that was a noob question alright, thankyou for your patience

I actually bought three of these from a local auction sight for approx $US30 - I was drunk when I was biding, $30 was meant to be my maximum bid, but I accidenty made it my first bid Anyhoo, ten bucks each...

Two of them are pretty terrible, in addition to being non functional, and bootlegs anyway, so I feel no guilt about converting them to test carts
PROG42G1 + CHA42G1
PROG4096B +CHA42G1
But one of them shows some promise of being a decent conversion at some time in the future
PROGBK1 + CHA521Y

The CHA42G1 boards look like this


And the M1 chips look like this (27C010A and 28F1000PC)


So at this stage I'm hoping I could buy these for a couple of bucks each, http://www.buyicnow.com/it.php?i=379 get them to burn the m1.bin for me, and that would be a good intro into my first MVS "conversion" - am I oversimplifing this?

 

[stj]

what are the 27c1001's for?
most of the chips you have are either bigger than that or eraseable.
just desolder the old chips and blank them.

 

[hatmoose]

what are the 27c1001's for?
most of the chips you have are either bigger than that or eraseable.
just desolder the old chips and blank them.

Thanks! My logic behind buying new(ish) 27c1001's for this is that I dont know if the existing ones are already damaged and I'm not yet confident in my skills and equipment burning new ones.
This will be the first time I've messed with neo-geo and I want to start with at least chips that I know are good so I dont have a troubleshooting nightmare if things go wrong

 

[hatmoose]

Finished this today, and managed to salvage one of the Puzzle Bobble carts into a playable state too.

I used the worst of the bootleg boards as the donor for the z80 test cart. Both the prog and char boards had been basically destroyed during the failed boot attempt, whoever did the initial boot obviously didn’t have desoldering gear, there were at least 20 missing/burnt pads. Luckily the m1 and s1 pads were immaculate. So I feel no guilt about taking a un-salvageable and non-functioning bootleg and recycling it into something useful.

The UX on the test bios is functional and extremely basic. if you just put the test bios in it will run the basic tests then output a screen like this, noting that the z80 tests were skipped.


if the z80 test cart is inserted it looks like this.


The test menu is a vastly more complete than the one in the stock or unibios, and it’s designed to test boards in unknown fail states. No graphics? It plays tones! No sound? It displays images!


i also managed to get some life out of one of the failed bootleg puzzle bobble carts. It’s now only a partially failed bootleg. It boots
the game, sound good, backgrounds good, sprites still glitchy. I’ve got bodge wires on top of bodge wires, one will still be wrong I think… It’s not pretty, but it’s what’s inside that counts. In this case what’s inside is REALLY not pretty.


so if anyone was looking at this and wondering if it’s worth the effort I would say yes. In my case I wanted to test my crappy Aliexpress MVS but with a tool like this I’d be confident that my poor skills would be enough to trace most MVS faults.