SNK Games (Neo Geo MVS / AES)

[channelmaniac]

Model: MV4
Symptom: Backup RAM error

Replaced both Backup RAM chips. Removed the foam from the underside of the bottom board as it was hardened and was causing corrosion of the board. Patched a corroded trace for the R/W signal to the Backup RAM. Board would boot but only slot 1 was working. Cleaned the top board, patched 8 bad traces, and tested. Board would play, but had incorrect sounds playing. Replaced a bad YM2610 IC and tested.

[channelmaniac]

Model: MV1F
Symptom: Low audio on right channel

Recapped audio section and tested. Installed a coin cell mod on the board and retested.

[channelmaniac]

Model: MV1
Symptom: Stuck on green screen

Cleaned board. Resoldered 32khz crystal and capacitors. Patched 2 traces to fix DIP switch 1 and 2. Recapped board to fix low audio issues on left channel. Replaced battery with a coin cell mod. Tested.

[channelmaniac]

Model MV2F
Symptom: Calendar Error

Removed leaking battery, cleaned board, patched 6 corroded plated thru holes in the power circuit for the D4990 clock/calendar chip, replaced 1 diode, and installed a coin cell mod kit. Removed damaged memory card slot connector. Tested board.

[channelmaniac]

Model: MV2
Symptom: Video RAM Error 8000 5555 0000

Replaced 2 bad CXK5814 SRAM chip. Removed battery, cleaned the board, and installed a coin cell mod kit. Replaced damaged memory card slot connector with one from a parts board. Tested.

[channelmaniac]

Model: MV2F
Symptom: Crosshatch of death. Severe trace damage.

Board was a parts board purchased in a lot. Someone had done a horrific job of removing the connectors from slot 2 and damaged many traces where they met the solder pads and in-between solder pads.

Removed battery and cleaned board. Removed the severely damaged memory card slot connector, installed 2 missing connectors for Slot 2 and tested. Board would not boot cartridges. Patched 1 trace for Address line A9 between the NEO-E0 at position F3 and Slot 1. Board would boot but not play sounds. Patched 2 traces between Slot 1 and Slot 2. Board would play carts in Slot 1 but in Slot 2 they had graphics and sound corruption. Patched 11 additional traces to restore Slot 2 to proper functionality. Installed a coin cell battery kit and tested.

[channelmaniac]

Model: Shock Troopers 2nd Squad (MVS Cart)
Symptom: Crosshatch

Replaced bad P1 ROM. Game played but had no sound. Replaced bad M1 ROM and tested game.

[channelmaniac]

Model: MV1
Symptom: Stuck on green

Cleaned corrosion from board as best as possible. Replaced a bad capacitor and crystal in the clock/calendar circuit. Tested traces around the area affected. Tested board.

[channelmaniac]

Model: MV4
Symptom: Slot 3 dead

Recapped audio section, cleaned top board, and jumpered a bad trace on the program ROM address bus to fix slot 3. Replaced the battery with a coin cell kit mounted to the bottom of the board. Tested.

[channelmaniac]

Model: MV4
Symptom: Low audio

Recapped audio section, cleaned top board, and replaced the battery with a NiMH type. Tested

[channelmaniac]

Model: MV4
Symptom: Lines on screen

Recapped bottom board, cleaned top board to fix lines, and replaced the battery with a coin cell kit. Replaced missing assembly hardware. Tested.

[channelmaniac]

Model: MV4
Symptom: Will not play some cartridges

Fixed 1 burned trace and 2 gouged traces on the top board. Tested.

[channelmaniac]

Model: MV4
Symptom: Work RAM error

Replaced bad SRAM IC. Tested board. Replaced sound caps and retested.

[channelmaniac]

Model: MV1FS
Symptom: System ROM Error, battery corrosion.

Removed old battery, cleaned board, and replaced the BIOS ROM. Tested. Repaired a bad trace between the sound RAM and the NEO-D0 chip to fix missing sound. Recapped the audio section to fix a low volume issue on the right speaker. Installed a coin cell battery kit and tested.

[channelmaniac]

Model: MV4
Symptom: Lines in graphics, random Z80 error, low audio.

Recapped audio section, cleaned the top board and slots, and tested.

[channelmaniac]

Model: MV4
Symptom: Memory error, lines and blocks on the screen.

Customer requests the installation of a coin cell battery kit and UniBIOS.

Replaced 1 bad surface mount Work RAM and 2 bad surface mount Video RAM chips. Replaced the BIOS with a UniBIOS 3.1 (Registered Version), replaced the battery with a coin cell kit, cleaned top board, replaced a bad 74F253 on the top board, and tested. No sound. Replaced bad YM2610 and successfully retested board.

[channelmaniac]

Model: MV4
Symptom: No audio

Board had (poorly) attempted repairs done. A 74AS244 was replaced, the audio caps were half done, and the HA13001 was standing off the board with the mounting hardware missing.

Recapped audio section. Replaced poorly installed HA13001 and installed missing hardware. Replaced bad YM2610 to restore audio during hardware tests. Board would play but had no audio. Another tech had replaced the 74AS244 at R1 and damaged a trace. Patched trace between pin 15 of the 74AS244 at R1 and pin 2 of the Z80 CPU at M1. Tested.