Capcom - Older Boards (Pre CPS 1)

[channelmaniac]

Model: Legendary Wings
Symptom: Corrupt Graphics

Replaced multiple 74LS245 chips and patched 3 broken internal layer traces on the video PCB. Tested.

[channelmaniac]

Model: 1942
Symptom: No sound

Replaced 2 physically damaged caps in the audio circuit and cleaned the edge connector. Tested.

[channelmaniac]

Model: Black Tiger
Symptom: Scrambled screen

Game would play blind. Board had bad corrosion damage to the CPU board.

Removed, cleaned under, socketed, and replaced IC 5C (LS367), 4D/5D (LS157), 1H (LS374), and the 2018 at 4C. This corrected the colors, but the screen was still scrambled. Cleaned the dirty video PCB and found the 32K x 8 SRAM's R/W pin was stuck high. Traced it back to a gouged section of PCB. Patched 2 traces to restore proper video, but with corrupt sprites. Replaced ROM 07 and ROM 09 to fix the sprites. Game would randomly reboot. Cleaned the legs on the CPU, protection CPU, and 5 program ROMs. Tested.

[channelmaniac]

Model: Commando
Symptom: 4 pics on screen

Replaced bad 74LS161 clock divider chips at 7A and 7D on the bottom PCB. Tested. Background would disappear, sprites were in the wrong location, and sprites were corrupt. Replaced a bad 74LS32 at 6D (pins 1 and 2 were shorted together internally) and the 74LS04 at 9E on the top board and tested. Background would still disappear, but instead of from the top to bottom of the screen with 1 pixel wide jagged swaths, it would disappear from left to right in 8 bit tall swipes at random. Replaced bad 6116 SRAM on the top board and tested.

Turned to the bottom board for sprite issues: Replaced bad 74LS283 chips at 2C, 3C, 4D, 5D, and 5E. Replaced bad 74LS163 at 6M and 74LS20 at 2E. Tested to find correct positions, but corrupt sprites. Replaced bad 74LS257 chips at 1K, 2K, 10K, 8L, and 8M. Replaced bad 74LS174 at 6M then 4 bad 2114 RAMs at 3H, 3J, 4H, and 4J. Sprites returned but had a line in them. Replaced bad 74LS194 at 9J and tested.

[channelmaniac]

Model: Super Buster Bros
Symptom: Dead. Suicided.

Removed leaking NiCd battery and cleaned the area of the PCB. Replaced ROMs at 11H, 13H, and 14H with ones programmed with suicide free code. Removed R13 and modded the PCB to use the code. Tested.

[channelmaniac]

Model: Sidearms
Symptom: Graphic corruption and no sound

Replaced a bad line buffer SRAM to fix every other sprite line missing. Replaced the other line buffer SRAM to fix a vertical dot missing every 8 pixels. Replaced the Sound RAM, 74LS138, 74LS74, and a bad bipolar PROM in the sound circuit. Replaced a bad cap in the reset circuit. Tested.

[channelmaniac]

Model: Section Z
Symptom: Missing every other horizontal line in sprites.

Replaced bad CXK5808 SRAM in the Line Buffer circuit. Tested.

[channelmaniac]

Model: Black Tiger
Symptom: Short. Shuts down power supply

Replaced shorted capacitor on the bottom of the CPU PCB and tested.

[channelmaniac]

Model: Speed Rumbler
Symptom: Corrupt sprites

Replaced 1 bad high speed 2018 SRAM and tested.