Red lines on Neo Geo

[tristan]

I just purchased a Neo-Geo 1 slot board and a Samurai Shodown (from different people on eBay), and when I plug them into my SF3 Alpha cab, all of the screens are filled with red lines, and there are red boxes around all of the text. I have 2 other cartridges, but they were sold as-is, and I get only a grid when they are plugged in (no red lines, but the neo-geo splash screen looks normal as well).

My question here is, would this type of issue generally be a cartridge that is bad, or the mainboard? Also, is there anyone near downtown Dallas that might loan me a known good cart to test? Maybe the monitor needs adjustment? If the cartidge was bad, that would suck, but I got it cheap. If it's the mainboard, I'll need to get upset with someone...



Note the blue area next to Insert Coin and the green blocks on either side of the title. They look red in real life. I'm having trouble getting a good picture.

Thanks

[vietofmars]

My brother has a neo geo one slot and he gets weird graphics when the cart isn't in all the way.  Try reseating the cart.

I'll ask him if it's the same as what you're seeing.

[Goz]

My brother has a neo geo one slot and he gets weird graphics when the cart isn't in all the way.  Try reseating the cart.

I'll ask him if it's the same as what you're seeing.

NEO MVS carts are also very prone to oxydation of the contacts. Take the cart out with power off of course. Take an eraser from a pencil and go over the contacts of the CART with the eraser. Blow out the contacts with air before inserting in the NEO board. This will resolve this sort of problem 9 times out of 10 with the 10th time being a bad cart or imporperly seated.

Hope this helps,

-Goz

[Stingray]

Goz is right on the money. That looks & sounds like dirty contacts to me. I have several carts that gave me similar problems before I cleaned them.

-S

[tristan]

Amusingly enough, I suggested someone use an eraser to clean some contacts about a week ago.... 


I'll try it again tonight. Thanks guys.

[ClubNinja]

It's also worth nothing that MVS carts tend to act up if they're inserted all the way into the slot.  I find that the best results happen by pushing the cart all the way in, then backing it out very slightly.  Every sound or image problem I've ever encountered with MVS was solved this way (and a good cleaning helps, too!)

[Stingray]

Thanks for the tip clubninja. My Captain Tomaday cart has no sound. I'll try backing it out a bit to see if that makes a difference.

-S

[ChadTower]

I'm always thinking about ways in which these simple (e.g. a cart) boards can fail.  Has anyone here ever seen a malfunctioning cart repaired by replacing caps?  Logically, if one or more caps in the sound circuit of the cart were crapping out, that could cause sound voltage levels to drop below proper threshhold on the motherboard, yes?

Or am I overthinking it?  ClubNinja, throw down some EE knowledge here.   

[Stingray]

I'm always thinking about ways in which these simple (e.g. a cart) boards can fail.  Has anyone here ever seen a malfunctioning cart repaired by replacing caps?  Logically, if one or more caps in the sound circuit of the cart were crapping out, that could cause sound voltage levels to drop below proper threshhold on the motherboard, yes?

Or am I overthinking it?  ClubNinja, throw down some EE knowledge here.   

It certainly seems possible, but I'm afraid my skill level is not anywhere near high enough to be able to locate said failed cap if that did in fact turn out to be the culprit. I did take the cart apart once and looked both boards inside over very closely. I didn't see anything that looked obviously cooked or damaged in any way so I put it back together.

-S

[ChadTower]

Yeah, caps aren't going to look any different when they die from age, and that is a very common cause of cap failure.  They just stop working, the electrolytes in them dry up.

[2600]

Do carts have electrolytic caps?

For some reason I want to say the only caps I've seen on carts are ceramic.

Got any pics of a cart?

[ChadTower]

I've seen some.  I would imagine not all do, but I'm pretty sure I've seen NES carts with one or two on the board, with the pins bent so the cap is horizontal.

[Stingray]

Do carts have electrolytic caps?

For some reason I want to say the only caps I've seen on carts are ceramic.

Got any pics of a cart?

If I think about it over the weekend, I'll take it back apart and scan the boards. I'd be suprised if anyone can diagnose anything from that, but I suppose it's worth a go.

-S

[ChadTower]

Don't press the scanner cover down on it, you're risking broken solder joints if you do that.

[2600]

One more question, do these carts have an audio board?

I thought they were more or less glorified memory devices.  Can't see anything positive about adding a seperate audio anything inside of a cart.

[Stingray]

There are two boards inside, as far as which one does what, I have no idea.

-S

[Stingray]

Not much in there I'm afraid. Don't appear to be any caps of either kind, but it was a good thought. I presume that the actual audio hardware must reside on the main board.

Edit: I forgot that this board shrinks down big pics. Full sized versions here:

http://www.stingraysmadness.com/misc/tomaday1.jpg

http://www.stingraysmadness.com/misc/tomaday2.jpg

-S

[ChadTower]

Is it me, or does that look like it may be missing chips?

ClubNinja, do you have this game to compare against?  I don't have it.

[2600]

I imagine it is common to use the same PCB for a lot of carts.  Ones that have bigger size ROMs, populate more of the board with the required ROMs.  Ones that don't like the above save money by not populating them.


Stingray, for your problem is there a self test that verify's your the ROMs on your cart are ok?  Also, I assume you have another cart to verify that your system acutally makes sound?

[Stingray]

If there's a self test for the roms, I don't know how to access it it. When my MVS is in test mode, I don't see that as an option. And yes, I have about a dozen or so MVS carts, this is the only one that has no sound.

-S

[Goz]

Just curious if any of our info has heled the original poster.

[ClubNinja]

Is it me, or does that look like it may be missing chips?

ClubNinja, do you have this game to compare against?

[Stingray]

It is a neat game. I'll probably end up buying another copy so I can have one that has sound.

-S

[ChadTower]

Does it have bacon?

[Q*Bert_OP]

Does it have bacon?

Nope

[Stingray]

Are you sure? There's lots of food in it. There might be bacon in a level I haven't played.

-S

[tristan]

Yes. I cleaned the contacts with an eraser, then cleaned again with alcohol. I re-inserted the cartidge, and pulled it out slightly. Everything is perfect now. Thanks! 

Just curious if any of our info has heled the original poster.