New MVS, new problems

So I got a new MVS to replace my old Z80'd board.
Arrived yesterday, traveling all the way from sunny South Korea. The board is a MV-1FZ and my old 1 was a MV-1FZS, so I thought I would literally be able to plug and play just by swapping over the JAMMA connector. Sadly this has NOT been the case!

Again I have no sound, so I did some checking on my wiring and found that the sound lead to the RGB port had snapped, so I soldered that back onto pin 11, part side. But still no sound, tried a few different carts, threw in my universal BIOS, but no change.

So in a act of dismay I put in my diagnostic BIOS along with my test cart and hello Z80 problems!
This is the error message I get.

Z80 REPORT ERROR CODE: 14
M1 BANK ERROR (16K)

Can I be this unlucky? Is there something simple I'm missing?

Please can anyone help? Before I learn to start swearing in Korean.

There's a chance your diag m1 (rom or cart) is incorrect, or maybe a fault on that board where your diag m1 resides? If something is very wrong with that m1 diag cart it could be killing the z80 side or maybe giving a false positive. Does unibios report z80 error with another game connected instead? It's a long shot but have you tested PSU voltage level, cleaned cart slot and carts up?

What size chip did you use for the M1? And is that the same size as what was on the cart originally? If you used a 27C010 for example (128Kb) and it had a 64Kb chip originally (which I have seen), then the upper address pin might be floating, which could give z80 errors.

I burned the Diag Rom and used a 27c1001, so it is a 128k eprom. Not sure what cart was used or the size of the M1 rom originally, possibly Puzzle Bobble or Super Sidekicks if I remember rightly.

If memory serves Puzzle Bobble had a 64Kb M1 I think. Maybe if the board is a boot there's an issue with the upper address pin. If you stick a game in and use unibios, do you get a z80 error again with the 'new' board?

Hi, thanks for replying.

I'll break down what I've done so far.

Original MVS MV1-FZS
Was playing on this for about 6 months, was playing Pulstar when I got a wierd sound error, was still playing game music on the Neo Geo splash screen.
This now gives a Z80 error on a black screen if you use the original BIOS. If I use a universal BIOS, it works but no sound, even if I try to use the jukebox, I can't remember the error message.

Pulstar, the user, not the game , burnt me some diagnostic ROM's, I put the M1 ROM on a Super Sidekicks board.
Running just with the diag BIOS everything passes.
Throwing in the diag board, I got this message.

Z80 SLOT SWITCH IGNORED (SM1)
SM1 OTHERWISE LOOKS UNRESPONSIVE
*I hit start*
Z80 DEAD / ERRORED / COMM. ISSUE
EXPECTED : C3
ACTUAL : 13

Click to expand...

New MVS MV1-FZ
I had to cut off the edge of the JAMMA connector since I wouldn't fit in, after that I plugged it in, I had sound but colours were off. Took off the JAMMA and reseated, ever since then I've had a normal picture but no sound.
I found that the sound wire had snapped off the JAMMA, so I soldered that back on, but there's been no change.
Unlike my other board, there is no Z80 error message, everything seems to work with the original BIOS in, just no sound. If I plug in my universal in and go to the jukebox, it works, no error messages, but again no sound.

I checked the voltages on the PSU, which is a JAMMA PSU with variable 5V, measured it and I get 5.03V and 11.93V.
I checked out the RGB scart lead today, JAMMA pin11 comes out at 2 pins on the scart lead.

With the diag BIOS in, everything passes, but I've noticed it seems to take awhile for the screen to sync. With the Z80 testing, unlike my other board, I don't need to hit start, it goes straight to the test, which gives me this.

Z80 REPORT ERROR CODE: 14
M1 BANK ERROR (16K)

Click to expand...

I do find it hard to believe I could be this lucky, so I'm REALLY hoping you can point out where I've gone wrong here.

From reading this (and scrolling down to M1 Bank Error) on the Diagnostics Rom homepage a few things maybe to check. Have you checked the continuity of the M1 rom on your CHA board to make sure there are no broken traces or lifted tracks.

If that's good, maybe check the CHA board is showing continuity from these two points:

NEO-D0 SDRD0 (45) → CHA SDRD0 (MVS: B47)
Z80 A15 (5) → CHA SDA15 (MVS: A58)


Also, maybe check the cartridge connectors are clean and the cart edge is clean. Does the same thing happen if you swap cartridge port risers from one board to the other (I'm sure they are swappable on the 1FZ and 1FZS).

Well, the M1 bank error is hopefully a broken trace or a dirty cart / MVS socket. Start by cleaning those up and examine the cart and MVS to see if you can see a damaged trace. Was this 'new' MVS described as working?

Have you adjusted the sound pot on the MVS - ie. It's not turned all the way down is it? You need to be careful feeding that into a scart lead as well btw - It's probably amplified and will fry the audio input on a TV if you're feeding it straight into the TV from the audio amp output.

Thanks for the replies.

I'll have another look at the board on the weekend, but tonight I did quickly wire my AES up to the TV using the same RGB scart lead and it worked fine, so don't think I've damaged my TV.

Eh, I didn't get round to looking at the board in the end on the weekend.
1st thing I was going to do was clean cart connector, can I just go crazy with my DeoxIT D5? How long should I leave it to dry?

Sorry for taking to long to reply

pulstar said:

NEO-D0 SDRD0 (45) → CHA SDRD0 (MVS: B47)
Z80 A15 (5) → CHA SDA15 (MVS: A58)

Click to expand...

I tried that, it all checked out. I've gone over the board and the game cart with IPA and given them a good scrub, still can't see any kind of broken track and getting M1 Bank error.

I am thinking it's possibly a failed M1 line on the Z80. Try swapping the Z80.

Gadget your a genius mate really enjoy the YouTube lessons.Did the z80 swap fix it Del?

1st of all, fuck my luck.

giggsy07 said:

Gadget your a genius mate really enjoy the YouTube lessons.Did the z80 swap fix it Del?

Click to expand...

Not got that far yet.
Thanks again for all the help, but a few last questions.

1. Where can I pick up a Z80 chip?
2. How do I go about replacing a chip like this easily?
3. Could there be something in my wiring/setup that has caused this problem. While I realise I could have been sold a dodgy unit, I now have 2 units with sound problems.

While I'd love to repair this, I am thinking of going to the members market to ask for a new slot 1, hopefully with less chance of getting screwed over.

It's a bit ironic that both have sound problems mate but gadget is the man to advise.Did you pick it up on ebay?If so get the seller to replace it or PayPal claim.Iv done it myself with a guy and he had no problem replacing it.Ivandjcarletti was ebay username.Sound guy loads of boards for sale cheap also.Try and confirm its nothing to do with your setup as you mentioned first.Test all harness connections.Sorry I can't be more help but I have a half dead board myself with backup ram error.Replaced those and got a new error so I understand the frustration man.Drive ya mad probing..