SNK Games (Neo Geo MVS/AES)

[channelmaniac]

Model: MV4 4-slot
Symptom: Garbage on screen. Will not play.

Removed 6 solid bell wire patches from the bottom of the board. Tested the board and found only 2 of those patches were needed and installed 30ga kynar patch wires. Removed 3rd-party installed NiCd battery and installed a coin cell kit. Tested.

[channelmaniac]

Model: MV2 2-slot
Symptom: Graphic corruption

PCB had battery damage to the NEO-ZMC2 chip and the chip suffered a short circuit and burned a hole in the PCB.

Removed the old chip and battery. Cleaned that area of the PCB. Cleaned and resurfaced the battery damaged pads and removed charred materials from the PCB. Installed a replacement NEO-ZMC2 chip from a donor PCB. Jumpered multiple pins that were missing pads and supposed to be grounded. Installed a Kynar jumper to connect the Vcc pin to +5v. Jumpered 2 battery damaged traces from the ZMC2 to the video subsystem and tested. Installed coin cell kit and retested.

[channelmaniac]

Model: MV1C
Symptom: Dead

Patched 2 dead data traces between the CPU and the memory chips. Tested.

[channelmaniac]

Model: MV1C
Symptom: Missing controls

Board had attempted repair damage on the resistor packs used to hold inputs high.

Removed 18ga wires and patched the damaged traces. Tested.

[channelmaniac]

Model: MV1F
Symptom: Stuck on crosshatch

Cleaned slot PCB and replaced both corroded slot connectors. Installed a coin cell kit and tested.

[channelmaniac]

Model: MV1F
Symptom: Video RAM Error at 00000000

Patched dead trace going to the R/W pin of the 62256 SMT Video RAM. Tested. No audio. Cleaned Stereo/Mono switch and retested. Installed coin cell kit and retested.

[channelmaniac]

Model: MV1B1
Symptom: Random reboots

Board reboots if you even bump it. Cleaned the dirty board interconnects with 100% IPA and a toothbrush. Reassembled and tested roughly.

[channelmaniac]

Model: MV1C
Symptom: Dead

Replaced blown 5A fuse and tested.

[channelmaniac]

Model: MV1C
Symptom: Backup RAM 0D00000 - Read B255

Removed corroded backup RAMs. Cleaned and prepped pads. Installed new SRAM and jumpered dead trace on upper RAM pin 18 to fix error. Tested.

[channelmaniac]

Model: MV1C
Symptom: Stuck on crosshatch

Cartridge slots and top of PCB were dirty and very oily. Removed battery, cleaned PCB and slots, and tested. No audio. Repaired gouged trace next to the cartridge slot and tested. Reinstalled the battery and retested.