Z80 Communication Problem +more

So I pretty much finished putting my cab together.
www.killerkorp.com/stuff/ng9.jpg

plugged in the wiring, everything seems to work well during hardware tests. Controls, sound, all good.

Then I put in 4 carts.. and something's not jiffy.. My gf says. why isn't there any sound?. I reply that some of the carts won't have saound unless you put in a quarter.

So i put in a quarter, no sound..
Go back to hardware tests. No sound.
check the wiring... it's good.

The i boot again and i get a message.. Z80 Communication Error.
I know the Z80 manages the sound for the Neo Geo.. question is.. what do i do now? Change the chip?
There was no smell, no smoke, So im a little confused..

There is also this that happens with the video display.
www.killerkorp.com/stuff/crosshatch.jpg
you can see at the top how it is curved to the left.

Any help is appreciated

History- have you ever had sound on that board ?
First thing to do is clean slots and cart contacts.

The flag on the top should be fixed with a tweak of the monitors horizontal hold.

thanx for a quick reply.

Yes, the board did use to have sound some 6 months ago before i put it away.
The when i rebuilt the system today, the first few times i went to the sound test (with no carts in) there was sound.

I put in the carts, and there was no sound. So i went back to the sound test, and there was no sound. I removed all the carts, and there is no sound.

I got the z80 communication error, on a soft reset (i'm running Unibios).
I don't think the problem is the carts since even when there are no carts there is no sound in the sound test.. or the jukebox.

i know the speakers and wiring is good since as i move u the volume you hear that white noise.

as for the video, this is as good as i can get the monitor to look (it was worse before). I also do not get this flag on another board that i have.

Split the boards then put back together making sure they are well seated.

I did that already i checked the soldering on the z80 chip. Everything looked nice, no cracks or anything.. also took a look along the board. Everything semed nice and dandy. no leaking capacitors or anything else.

Nothing changed after i put it back together.

So i'm taking the time to clean all my games, and i'll be cleaning the port on the MVS aswell. I took the time to check the voltages on my machine. and +5 is good (5.01, wasn't able to make it any better).
+12v is actually more in the 12.40 and the -5v is actually -4.47

Does that difference matter? expecially on the 12v since it powers the sound?

Well, im glad to say it works now..

i think giving it a few days off really helped it get back on it's feet after i abused it when i first installed it (on/off every 5 minutes)

Well that's it then.. Thank you for the help

katarak said:

+12v is actually more in the 12.40 and the -5v is actually -4.47

Does that difference matter? expecially on the 12v since it powers the sound?

Click to expand...

The 5 volts is crucial, 12 volts supplies only the audio output stage so its not going to affect the digi sound (and on most psus its rarely spot on 12 volts anyway). The - 5 is not connected.

You should have more range on the 5 volts adjust, but if your set up is working- later.