Sony ZN2 probz.

[ChicksOnLeashes]

Hi!
I came up on a couple dollars, so I acquired a Street Fighter EX2 Plus board from an ebay listing.
The board was sold as "100% functional".
The game seems to run fine, but if you preform a memory check, some roms appear as NG instead of OK. Does that mean "not good?" haha. the memory check freezes and I will have to restart the cabinet.
Using a line output converter, I built a 4 pin connector to give it that sexy Q-sound, but setting the switch to stereo AND in the test menu causes the sound to be garbled to an extent. It does let me play mono sound through the line output converter RCA connectors, though.
Froze once during a match. The game will lock up during the demo screen eventually, as well.
I inspected the board closely a couple times and it doesnt seem like there is any visible issues. I reseated the eproms too, still the same. Should I clean the pins?
Voltage is at 4.99.

The seller is offering some money back or ship it back to them, so here a question...
Would it be smart to choose money back and use that to purchase a eprom programmer to repair the board and use in the future? Or just get the replacement board?
Do you guys think it is only an eprom issue and reprogramming the chips will -probably- fix it?
Thanks.

 

[twistedsymphony]

You are correct that NG = Not Good

however just because a ROM is reporting as NG doesn't mean that the ROM itself is bad, the issue could be with any of the circuitry between the ROM and the main board.

Obviously dumping and verifying the ROM is a good first step, but I think out of the dozens of PCBs I've had where a ROM reported bad in test mode, I think only twice was it ACTUALLY a bad ROM.

given that multiple ROMs are reporting bad, and that there is a clear pattern between the good and bad ROMs, I'd say there is likely a bad 74 series logic, buffer, PAL, or trace damage, I would be surprised if you actually had half of the MASK ROMs on a ZN2 board go bad like that.

As for your sound issues...
for mono: set the stereo/mono switch near the heat sync to mono, set the game to mono in the test menu and use sound through the JAMMA edge
for stereo: set the stereo/mono switch near the heat sync to stereo, set the game to stereo in the test menu and use sound through the Stereo header; not the JAMMA edge.

 

[ChicksOnLeashes]

You are correct that NG = Not Good

however just because a ROM is reporting as NG doesn't mean that the ROM itself is bad, the issue could be with any of the circuitry between the ROM and the main board.

Obviously dumping and verifying the ROM is a good first step, but I think out of the dozens of PCBs I've had where a ROM reported bad in test mode, I think only twice was it ACTUALLY a bad ROM.

given that multiple ROMs are reporting bad, and that there is a clear pattern between the good and bad ROMs, I'd say there is likely a bad 74 series logic, buffer, PAL, or trace damage, I would be surprised if you actually had half of the MASK ROMs on a ZN2 board go bad like that.


As for your sound issues...
for mono: set the stereo/mono switch near the heat sync to mono, set the
game to mono in the test menu and use sound through the JAMMA edge
for stereo: set the stereo/mono switch near the heat sync to stereo, set
the game to stereo in the test menu and use sound through the Stereo
header; not the JAMMA edge.

So you're saying i should go for a full replacement, huh?! Hahaha.

Are the logic, buffer, and pal chips are all drop in replacements? As in, there isn't any game specific information burned on them? Would I also need an eprom programmer to check if they're still good?

I will also add this, one of the previous owners also soldered in a resistor on the jamma pins from ground to 5v.

As for the audio, setting both the stereo switch and the test menu to stereo result in garbled sound. Some of the music plays and it sounds great, but everything else is ruined.

 

[twistedsymphony]

Are you getting audio from the stereo header? Because it will be garbled on the jamma edge if you enable stereo .

 

[ChicksOnLeashes]

Are you getting audio from the stereo header? Because it will be garbled on the jamma edge if you enable stereo .

Yes. Its a Blast City cabinet. Disconnected jamma audio, connected RCAs with a line output converter to the 4 pin on board stereo connector, switch test menu and on board switch both to stereo.