z80 error

[konrad]

The z80 error screen appears, could it be the chip or some cut track?

 

[ack]

It could be either, or the z80's ram. However the first thing you should do is clean your cart's edge connector and the cart slot.

 

[HeavyMachineGoob]

Z80 error is sadly very unspecific, it can be a lot of different things.

You may want to get a Diagnostic BIOS, plus the M1 ROM on a CHA board to diagnose this.

 

[konrad]

Where can I find the z80 ram memory?

 

[HeavyMachineGoob]

In your pictures, the Z80 ram is that thin chip BR6116 below the SM1 ROM, the board says 6116 in white text next to it.

Z80 ERROR - NeoGeo Development Wiki

wiki.neogeodev.org

See here in this article, the Z80 error means a connection or chip issue is present between the Z80, the SM1 ROM, the 2K 6116 SRAM and the YM2610.

Some of the needed traces for these chips are near the battery, it is very common for battery leakage to destroy those traces, a person would have to patch over these traces with wires. In severe battery damage cases, the YM2610 and the traces underneath it can get destroyed by corrosion.

 

[Jarryson]

hi, I have repaired some z80 error last month. First of all check conectivity between z80, ram 6116, sm1, y2610 and D0. If traces are OK then try to change z80 ic or 6116 ram. Last 2 mv1f I repaired, one had a bad z80 ic and the other a bad 6116 ram.

 

[HeavyMachineGoob]

Should also note the Neo Geo MVS requires a Z80A specifically, not a plain Z80. The difference is the Z80 is a 2MHz chip and the Z80A is rated for 4MHz.

SNK would sometimes cut costs and use the slower Z80, the problem is the MVS puts extra stress on this CPU which can cause premature failure years and decades down the road. Of course, it wasn't a big deal in the short term.