MVS 1-slot won't leave test mode (acts like no cartridge installed)?

So, this is the same MV-1F 1-slot board that was having trouble with the video sync last week. I repaired the video sync, so with no cartridge installed, I get the test screen now (test grid) and I can cycle through the input test, sound test, memory card test, etc by pressing the player one button. *All* of the dipswitches are off (I've verified this by looking at the input test, and it shows all of the dip switch settings as 0).

When I plug in my new Puzzle Bobble cartridge and power up the board, it still just shows me the same test screens I got *without* the cart installed. I've checked all of the obvious stuff (the cart is plugged in correctly, I've wiggled the cart to make sure it's securely plugged in, I double checked to make sure all of the dip switches are turned off, I've made sure the test switch on my cabinet is off, heck I've tried it with the test switch on too), but I still just get the test screens. As far as I can tell, the board acts the same whether the cartridge is plugged in or not.

Any tips for me? I may just have a bad cartridge, but I'd expect that the PCB would give me some sort of error screen, instead of just acting like there's no cartridge installed at all. I have a friend with a working 1-slot board which I'll use to test the cartridge when I get a chance, but I'm hoping someone might be able to point me in the right direction.

Am I just missing some simple step? Am I being stupid somehow? Or is it possible that my PCB has another problem that needs to be repaired? If so, where's a good place to start? Nightmare Tony?

Thanks for any help!

-druid

I think I mentioned this before ? but have you checked your voltage off of the power supply ?

My voltages are all very close on 12V and 5V (slightly under, but like 0.1 or 0.2V only).

One other question - I know that another thing that can cause this is having the cartridge installed upside down. I have the cartridge installed with the arrow facing *down*, which I presume is correct. I can try turning the cartridge over and installing it the other way, but I'm afraid to try that for fear it might damage my system. Can it?

-druid

[ August 08, 2002: Message edited by: bigdruid ]</p>

Check the area around the cartridge input socket, and look for any loose soldering/broken connector legs/Burn markings, and exploring the rest of the PCB for any of those isn't a bad idea either. Make sure to use caution when exploring the PCB, static is not your friend.

There's no obvious signs of repair on the PCB itself (nothing resoldered or anything). I've checked a bunch of the pins on the edge connector where the cart plugs in with my logic probe, and there's signals on a bunch of them (doesn't mean much, but at least *some* signals are getting to the cart).

I opened the cart itself, and there are some signs of repair work on the top board in the cart (some wiring has been done) - I can't tell if it came that way from the factory or if some previous owner was hacking it, though. The guy who sold it to me over ebay claims it was working just fine before he sold it, but you have to take that with a grain of salt, I guess.

-druid

Hmmm....check if any of the soldering looks like it might have accidentally spilled over to another connector.
An see if any of the wires are damaged.

Hi
Try turning the cartridge round so that the arrow is on the top and the name of the cartridge is upside down,i think you have got it round the wrong way.It threw me when i first got my cab aswell.
Hope this helps.

So, I inspected the cartridge again. The repair or modification done to the cartridge is pretty clumsy, but as far as I can tell there's no solder accidentally bridging connections, and the wires themselves are sound (I checked them with a multimeter).

I tried flipping the cartridge over - however, it was not physically possible to plug the cartridge in upside down, because one edge of the cartridge is thicker than the other, so the 1-slot PCB I have only lets the cartridge plug in one way (with the arrow *down*).

Other things I've tried so far:

1) Plugging the cartridge in really hard
2) Plugging the cartridge in half-way
3) Cleaning the contacts on the cartridge

When I get home from work tonight, I'll try running the cartridge with the top cover off so I can take some readings with my logic probe, and see if the signals are getting to the board or not.

One other thought that occurs to me - there are 2 boards in the cartridge, and maybe a previous owner swapped them around or turned them upside down *inside the cartridge*? It's currently plugged in with the component side of the boards *up*, which seems correct, but you never know...

-druid

Actually it wasnt a joke!!
Thats the way my cartridges work on my board so just goes to show what you know!
Just trying to help the guy,thats what these forums are for,which is more than i can say for you.

well its an mvs 1-f. so the carts go in horizontally, right?

the actual cartridge slot pcb is detachable. maybe its loose or there could be some dirt/debris in there. check that out.

it obvoulsy sounds like the board isnt reading the games.

you should try some of your friends games in your board aswell, maybe it is the puzzle bobble.

From the sounds of it, do all the ceramic EProm chips in the cartridge have glass windows and as you said, lousy looking wiring? That might be a bootleg cartridge. You will wanyt to return it and demand a refund. If all the rom chips are plack plastic with Toshiba on them and a number like "068-P1" or 068-C8" then its a real cartridge. Also, is the label a photocopy stuck on or does it look like the real thing?

I DO recommend you try it at your friend's place. If it doesnt come up, chances are that its the cartridge.

The most common cause is dirty edge contacts. Bootlegs are usually made from modified older cartridges, so their edges would be dirty as heck; the pirates dont care.

In the way the game is programmed, the first part of the cartridge programming is a header set with 6 characters of NEOGEO. The game board MUST recognize this code to assume that there is a cartridge installed. A snapped or open address or data line will cause it to not recognize the cartridge at all.

Back to it being a boot, it may never have worked to begin with.

good luck and hope you got the real thing.

Thanks all, and thanks Tony.

Yes, I have a strong suspicion this was a bootleg cart - the chips are all eproms (not ROMs or PROMs - they all have erase windows). Also, the eproms on the bottom board just have some weird arcade marquee sticker covering all of them, which seems odd for an authentic cartridge. And the label does look a little funky. Basically, it looks like someone modified an old cartridge and plugged in new eproms.

In any case, this weekend I received a different cart (Pulstar) and it works just fine in my board, so I'm positive this is just a bad PCB. I'm returning it to the seller.

Thanks again for all of your help!

-druid