6 replies to this topic

[5-11under]

Hi all,

I'm trying to repair a Neo Geo for a friend. I'm not too familiar with these...

I've got some Japanese fighting game plugged in (something "2"). The splash screen shows up, stating "MAX 330 MEGA" and "PRO-GEAR SPEC" in the middle of the screen, and "SNK" at the bottom of the screen. At the top, the "NEO GEO" graphic should show up, spinning and whatnot. It does... however, it's at the very right of the screen, with half of it cut off (beyond the right of the screen... .). During the demo of the game that follows, some items are also too far to the right, with some items displaying correctly in the middle (usually text). The fighters are usually displayed too far to the right, and sometimes they've got parts missing from them. With no cartridge plugged in, a yellow screen shows up. The sound is fine.

I've replace two pairs of RAM that are near the 176 pin "LSPC2" chip. One pair was a "5863" DIP, and one pair was a "43256" SOIC. The RAM swap at least didn't do any harm, because the symptoms I'm getting are exactly the same.

Have I selected the wrong RAM to swap out?

If it's a RAM problem, there's only a few choices left: a "6116" DIP by the Z80, a pair of "43256" SOICs by the 68000 and YM2810, and a pair of "4364" DIPs fairly close to the 160 pin "NEO-B1"

Other details: Model NEO-0, serial number (90A)180618, board NEO-AE@3-5.

Any help would be appreciated by both me and retroillucid.

Thanks,
5-11under

[5-11under]

Anyone?

[save2600]

Last Neo*Geo I repaired just had bad solder joints and needed a real good cleaning in its cartridge port(s). Symptoms were blocky/garbage randomly on the screen and image off center IIRC.

Check for cold (broken) solder throughout, but especially near the cartridge port. Gotta love those kinds of fixes when applicable

[5-11under]

save2600, on Wed Aug 3, 2011 4:51 PM, said:

Last Neo*Geo I repaired just had bad solder joints and needed a real good cleaning in its cartridge port(s). Symptoms were blocky/garbage randomly on the screen and image off center IIRC.

Check for cold (broken) solder throughout, but especially near the cartridge port. Gotta love those kinds of fixes when applicable

Thanks. I'll give that a try... there's a lot of connections on the cartridge port.

Edited by 5-11under, Wed Aug 3, 2011 5:12 PM.

[the.golden.ax]

Wow, that is a new one on me. Is this a system that worked previously? I'd love to see what it looks like, and on what kind of TV/monitor this is being used on. (doubting this is the issue, but it isn't a PAL/NTSC issue?) I know you change the crystal. Usually though that comes up black and white and the bottom of the screen is cut off and at the top.

AX

[5-11under]

the.golden.ax, on Wed Aug 3, 2011 5:30 PM, said:

Wow, that is a new one on me. Is this a system that worked previously? I'd love to see what it looks like, and on what kind of TV/monitor this is being used on. (doubting this is the issue, but it isn't a PAL/NTSC issue?) I know you change the crystal. Usually though that comes up black and white and the bottom of the screen is cut off and at the top.

AX

No, it's not a PAL/NTSC issue - everything would be more consistently bad... I just checked the crystal near the CXA1145 chip, and it's 3.579545 MHz, so it's NTSC.

I'm running the composite output to a 1702 monitor. All of the text is centred properly, but lots of the graphics are shifted 1/2 screen to the right. I'll take some pictures before I continue any repair attempts.

[Official Ninja]

You should post over in the tech support section at neo-geo.com

Lots of fantastic, smart people over there that know all about the Neo-Geo.