Neo Geo MVS 4 cart system

I recently acquired a 4 cart MVS system that gets power and the control panel and marquee light up and I can hear the speakers kick in but I get no picture. I hear the tube humming but still no pic. Two things to not 1. the power supply doesnt seem to be kicking out enough juice and 2. there is a connection on the monitor that I cant seem to find where it plugs into. This connection seems to connect v-hol, h-hold etc. to another board but I cant see where on the MVS board and there are no other boards in there. Am I missing a board???

If you hear humming and the tube glows, you are getting high voltage to the monitor which is good. There should be 5 leads that go from the Jamma harness to the monitor. R,G,B, Video Sync and Video Ground. You should also have two wires going to the monitor off the isolation transformer for 120V power, and (maybe) a smallish ribbon cable that runs from the monitor chassis to a small board with pots on it to adjust h-hold, v-hold, limits, etc.

There should not be another board.

Why do you say the power supply does not seem to be outputting enough power? Some supplies have an adjustment screw to tweak the output. You really need a multi-meter to fine tune the power supply.

If your power supply is set too low, the PCB will not come up and you will get the symptoms you describe. You can try turning everything on and then turn up the power on the supply until it comes on, but this can be dangerous unless you have a meter on it. Don't go up too much or you could fry the board.

Hope that helps, let us know how it turns out.

I have already tried turning the power supply up and it still doesnt work. How would I check to see if the board is fried?

The sub pcb with the hor, vert hold, bright, contrast pots connects to the monitor pcb.

Back to basics. Do you have that small sub pcb, with the control pots on ? If not you need to get one

You should still get the NeoGeo intro sound with a cart inserted on boot up, if the sound is turned up.

I hooked up my 4 slot to another jamma set-up and I am now getting

VIDEO RAM ERROR

ADDRESS WRITE READ
000000000 0000 0400

Uh oh...that could have been from turning the power supply up, depending on how far you did it.

Can it be repaired?

That RAM error doesnt sound so much like a blown RAM as more like a loose or stuck pin line. Lemme see, 0400, hi ram, d2. Since its a flat pack RAM, this would correspond to pin 13, location 9L. Its the F9 line. It travels to the LSPC-A0 chip, pin 69.

ONLY RESOLDER IF YOU ARE ABLE TO WORK WITH FLATPACK CHIPS.

If you are around Los Angeles, I will do it on a freebie of you drive over. If not, then find a tech who is able to.

Where is a good place to find any of the above mentioned chips on the net?

After examining the board further I found a pin that isnt soldered down all the way. It says Inbound W242585-70LE. Two other things to note my ram chips are CXK5846, what can I use to replace them if I need to and there is a socket that looks like it is missing a chip the top says SC1 an the bottom says SC2.

Never heard of an Inbound ram. Most interesting, prolly a newer one put on improperly.

Tghe 5864s are the pallete color RAMS. They are not compatible with the video rams.

SC1 and SC2 indicates you have the older style MVS4 board, which isnt the MV4F. The older one was all TTLs for gating logic instead of a lot more flatpack customs. The two empty 40 pin sockets were going to be used for sprite graphics, such as the eye catch logo (the programming name of the neo geo logo). Since the standard set is to always include that graphic in the cartridge, it was deemed a chipset that wasnt needed.

I am getting a error as well ... first I had corrupt graphics, I cleaned everything and then I got this?

Address Write Read
00000000 55555 4555

Please help???

What do I need to do?

Since its a single stuck bit atthe beginnignt, I think a loose pin on a RAM isd top blame. Too tired to pull out the schematics right now, but its the higher of the two rams. 4 - 5 00000100 vsa. 00000101....the d0 line, pin 11 of the RAM is a loose pin.

Move it with a pin and if its loose, resolder it carefully. IF you have liquid flux, brush at arocc first (rosin flux, NOT acid flux!!!). Thaty will help give a smoother flow action.