SNK Games (Neo Geo MVS / AES)

[channelmaniac]

Model: King of Fighters 96
Symptom: Corrupt Graphics

Cleaned the cartridge edge connectors with a pink pencil eraser and tested.

[channelmaniac]

Model: MV1F
Symptom: Video RAM Error $8000

Replaced bad CXK5814 SRAM chip and tested. Board had a badly leaking battery. Removed the battery and a 470 ohm resistor from the charging circuit. Cleaned the board and installed a coin cell battery holder and CR2032 battery.

[channelmaniac]

Model: MV1
Symptom: Backup RAM Error

Board had a leaking backup battery which ate traces. Removed the battery, replaced 1 SRAM chip, and jumpered 3 corroded traces. Board would boot but was stuck on a green screen - a calendar error. Jumpered a bad trace and replaced the 32.768KHz crystal for the clock/calendar chip and tested. Board would not read DIP Switch 8. Jumpered another bad trace, installed a coin cell battery and holder then tested.

[channelmaniac]

Model: MV1
Symptom: Stuck on green (Calendar error)

Board had a leaking backup battery which corroded the 32.768KHz crystal for the clock/calendar chip. Removed the battery, replaced the crystal, installed a coin cell battery and holder then tested.

[channelmaniac]

Model: MV4
Symptom: Dead. Nothing on screen.

Replaced bad Work RAM, cleaned top board, installed coin cell battery kit, and tested.

[channelmaniac]

Model: MV2
Symptom: Stuck in watchdog

Board came in with garbage on screen and clicking sound, a classic stuck in watchdog problem. Replaced bad BIOS chip, replaced 2 bad SRAM ICs, removed leaking battery from board, cleaned, installed coin cell battery mod, then tested.

[channelmaniac]

Model: MV2
Symptom: Stuck in watchdog

Removed leaking battery and cleaned board. Removed damaged memory card slot connector. Its pins were bent and touching each other. Board was then stuck in Calendar (green screen). Replaced crystal to no effect. Replaced D4990 IC and tested.  Removed the 470 ohm resistor then installed a coin cell battery and holder in place of the NiCd battery. Replaced physically broken headphone jack and headphone volume control. Installed a replacement memory card slot connector then tested board.

[channelmaniac]

Model: MV4
Symptom: Work RAM Error

Replaced a bad surface mount Work RAM IC and tested. Board then came up with a Video RAM Error message. Replaced another bad surface mount SRAM and tested. Board had poor audio levels. Installed an audio cap kit, replaced the leaking battery with a coin cell conversion kit, and tested.

Cleaned the top board, reset the calendar, and tested one last time.

[channelmaniac]

Model: MV2F
Symptom: Cannot control audio on left channel

Left channel audio was full blast and couldn't be controlled by the volume slider. Recapped audio section, replaced volume control, replaced leaking battery with a NiMH battery, and cleaned the board. Tested.

[channelmaniac]

Model: MV4
Symptom: Video RAM Error $8000

Replaced bad CXK-5814 SRAM IC. Board had no audio. Recapped audio section then tested.

[channelmaniac]

Model: MV2F
Symptom: Backup RAM Error

Board had battery leak damage.

Cleaned the board. Patched 2 traces on the HC32 IC to fix backup RAM error. Patched 4 traces on the NE0-ZMC2 IC and one on one of the NE0-257 ICs to fix graphic corruption. Jumpered a bad power trace to fix the Calendar Error. Resoldered a popped pin on one of the NE0-G0 ICs to fix slot 2 not working.

Removed the 470 ohm resistor from the charging circuit and installed a coin cell battery and holder.

Retested board.

[channelmaniac]

Model: MV2F
Symptom: Dead. Stuck in watchdog

Board had a leaking battery which damaged the board by eating several traces.

Replaced a bad BIOS IC and 2 Work RAM ICs then the board would boot but had graphic corruption and an intermittent Z80 error and no sound. Patched a bad trace on address line A7 between the SM1 ROM and the 6116 to fix the Z80 error and sound problem. Replaced a NE0-257 IC that had a pin corroded through. Patched a trace between the NE0-257 and the NE0-ZMC2 IC. Patched 4 traces between the 2nd NE0-257 and the NE0-ZMC2 IC. This brought most of the graphics back. The output of the NE0-ZMC2 IC was racing on one pin. Replaced the NE0-ZMC2 IC to finish fixing the graphics issue.

Removed the 470 ohm resistor from the charging circuit and replaced the leaking battery with a coin cell holder/battery.

[channelmaniac]

Model: MV2
Symptom: Dead. Click of death.

Board had batter leak damage.

Replaced the Work RAM and Backup RAM. Fixed a bad trace in the battery backup circuit. Board booted with a Backup RAM error. Jumpered a corroded trace to the upper Backup RAM's R/W line. Removed the 470 ohm resistor and installed a coin cell battery and holder. Tested.

[channelmaniac]

Model: MV4FT2
Symptom: Crosshatch of death

Board had no battery leak damage and had already been converted to a coin cell battery. Board would only recognize cartridges when tilted up on its side, otherwise it was stuck on the crosshatch.

Board had been previously worked on. Someone replaced the caps and put large blobs of solder on every joint. All of the surface mount ICs on the top board had been reflowed.

Used liquid rosin flux and a hot iron to properly flow all the solder on the caps. Jumpered one damaged solder pad. Connector CN10 on the top board had come apart and wasn't fully seating to the bottom board. If pressure was put on the connector the games would boot. Replaced the bad connector and tested.

[channelmaniac]

Model: MV4
Symptom: Video RAM Error

Replaced 2 CXK5814 SRAM chips and tested.

[channelmaniac]

Model: MV1F
Symptom: Z80 Error

Board had been worked on previously and had the Z80 replaced.

Board had damage under the Z80 socket. Removed the socket, traced out the connections, installed a new socket, jumpered 2 bad traces, and reinstalled the Z80. Tested board.

[channelmaniac]

Model: MV2F
Symptom: Garbage on screen

Board had a Video Memory error which was causing garbage on the screen. When the pins on the chip were touched it would change the screen image drastically. Board had some liquid damage on the Video RAM that ate the trace to address line A0. Jumpered one trace and tested the board.

[channelmaniac]

Model: MV6
Symptom: Calendar Error

Could not duplicate issue. Resoldered customer installed clock/calendar crystal. Cleaned board set, installed audio cap kit, and a coin cell mod kit. Tested board.

[channelmaniac]

Model: MV4
Symptom: No audio

Board was worked on by another tech and was missing an IC

Replaced missing audio DAC. Tested. Board had no audio but did have digital audio working. Recapped board. Board worked but had audio corruption. Replaced bad YM2610 and tested.

[channelmaniac]

Model: MV4
Symptom: Low audio with scratchy sounds on all slots

Recapped audio section to fix low audio. Board not only had scratchy sounds but other sounds would mysteriously drop out. Replaced a bad YM2610 audio IC and tested.

[channelmaniac]

Model: MV4
Symptom: Stuck on Green (Calendar error)

Removed leaking battery. Replaced bad clock/calendar crystal, cleaned board, and tested. Repaired one bad trace on the data lines running under the battery. Installed coin cell battery mod. Tested.

[channelmaniac]

Model: MV1
Symptom: Graphic corruption

Removed leaking battery and cleaned board. Repaired a bad trace on the cartridge riser board. Tested. Installed a new NiMH battery, reset NVRAM, and retested.

[channelmaniac]

Model: MV2
Symptom: Graphic Corruption - leaking battery damage

Battery was already removed from the board. Removed the corroded NEO-ZMC2 IC. Cleaned the pads and installed a replacement ZMC2. Ran 5 jumper wires to patch bad traces to/from the ZMC2. Ran a jumper from slot 2 to the NEO-257 IC buffering one of the Graphics ROM banks on the cartridge to fix the remaining graphics corrosion. Tested board. Installed a new NiMH battery, reset the backup RAM, and tested.

[channelmaniac]

Model: MV1
Symptom: Garbled graphics

Board had been worked on before, but didn't appear damaged.

Removed component lead from under the peeled back cardboard/foam protector on the bottom of the board. It was shorting out traces under the foam. Reflowed the solder joints on a customer installed cap kit. Cleaned riser board/slots. Replaced the NiCD battery as it had just started getting crystalline growth on the negative side. Tested board.

[channelmaniac]

Model: MV4
Symptom: Backup RAM error: Read AA8A

Replaced bad SRAM at IC F9 and tested. Board had almost zero audio output. Installed audio cap kit and retested.