Author Topic: Midway Games (Read 107409 times)

channelmaniac · « **Reply #180 on:** September 20, 2014, 03:07:50 PM »

Model: Galaga
Symtpom: Dead. Garbage on screen

Replaced all the 24/28/40/42 pin sockets. Cleaned the pins on the customs and repaired a pin on one 08xx. Replaced the electrolytic caps on the boardset and tested.

channelmaniac · « **Reply #181 on:** September 20, 2014, 06:57:44 PM »

Model: Galaga
Symptom: Dead, garbage on screen

Board had previous repairs. CPU board was populated with 24/28/40/42 pin machine pin sockets already.

Cleaned copious amounts of hot glue off of the CPU board and recapped it. Replaced the 1000 ohm and 2200 ohm resistor packs on the video board. Cleaned all the hot glue off the Video board and installed new 24/28 pin sockets on it. Replaced 2 broken .1uf ceramic capacitors and replaced the old 470uf electrolytic capacitor. Cleaned the custom ICs, replaced the 00xx and 07xx ICs as they had multiple broken legs when pulled from their old sockets.

Tested board.

channelmaniac · « **Reply #182 on:** September 20, 2014, 10:03:12 PM »

Model: Galaga
Symptom: Corrupt Graphics

Board played but the characters were split in two with every other vertical line of the characters separated by about 1/2 of a screen. Replaced bad 74LS161 at 5D. Tested.

channelmaniac · « **Reply #183 on:** September 22, 2014, 09:07:44 PM »

Model: Galaga
Symptom: Garbage on screen

Recapped the boardset and replaced all the 24/28/40/42 pin sockets. Replaced the old style resistor packs on the CPU and video boards, cleaned the custom ICs, and tested.

channelmaniac · « **Reply #184 on:** October 03, 2014, 07:40:43 PM »

Model: Galaga
Symptom: Crashes and reboots

Replaced the 2200 and 1000 ohm resistor packs on the video board with epoxy encapsulated types. Replaced all 24, 28, 40, and 42 pin sockets with dual wipe sockets. Cleaned pins on the custom ICs and recapped board. Tested.

channelmaniac · « **Reply #185 on:** October 19, 2014, 03:26:34 PM »

Model: Galaga
Symptom: Colors wrong and starfield too fast

CPU board was already rebuilt. Replaced 24/28 pin sockets and old style resistor packs on the video board. Cleaned the custom ICs and tested. Starfield problem was now gone, but the color RAM stayed the same. Replaced RAM at 6K to fix color issue.

channelmaniac · « **Reply #186 on:** October 19, 2014, 06:23:53 PM »

Model: Galaga
Symptom: RAM Error

Board had attempted repair damage.

Replaced all the 24/28/40/42 pin sockets and old style resistor packs on the CPU board and video board. Replaced the 6 RAM sockets to fix the RAM error. Replaced a bad PROM at 1D on CPU board to fix incorrect sound effects.

channelmaniac · « **Reply #187 on:** October 22, 2014, 09:36:23 PM »

Model: Ms. Pac Man
Symptom: Dead. Garbage on screen.

Ribbon cable was physically damaged and had wire extensions soldered to the bottom of the board. Removed the extensions, replaced the ribbon cable, and tested.

channelmaniac · « **Reply #188 on:** November 28, 2014, 10:22:22 PM »

Model: Mortal Kombat II
Symptom: Will not play game

Coin up and try to play the game and it will only display "Game Over" and go back to attract mode.

Reflowed custom DMA Controller IC at UE13 and tested.

channelmaniac · « **Reply #189 on:** November 28, 2014, 10:24:09 PM »

Model: Mortal Kombat II
Symptom: ROM Error on sound board

Board failed diagnostics with 2 bong sounds indicating a bad ROM. ROM checksum was good. Patched gouged trace next to IC U24 and tested.

channelmaniac · « **Reply #190 on:** December 01, 2014, 10:20:57 PM »

Model: Pac Man
Symptom: Dead. Colored stripes on an unstable screen.

Replaced broken socket attached to the Sync Buss Controller daughterboard. Replaced the single wipe socket on the game board with a double wipe socket. Board would boot but had the aforementioned issues.

6MHz clock signal from the 74LS368 was unstable and causing strange symptoms including horizontal colored stripes across screen, screen jittering, and random rebooting. If the logic probe was placed on pin 11 of the 74LS161 at 2E the screen would become more stable. Replaced 74LS161 at 2E and the color RAM at 2D. Removed short under the IC at 2E between pin 9 and the 6MHz clock signal. Tested. Replaced Pac Plus PROMs at 4A and 7F with Pac Man PROMs. Installed zip ties on the 2 daughterboards and retested.

channelmaniac · « **Reply #191 on:** December 03, 2014, 07:07:50 PM »

Model: Pac Man
Symptom: Will not boot into game. Board had a speed-up puck installed.

Removed puck. Resoldered cut leg on 8C, replaced bad ROM at 6F, and tested.

channelmaniac · « **Reply #192 on:** December 03, 2014, 09:32:57 PM »

Model: Ms. Pac Man
Symptom: Dead. Missing ROM and daughterboard cable.

Repaired multiple burnt edge connector contacts. Replaced missing cable and missing ROM at 6F. Board would not boot. Replaced bad IC sockets at 6E, 6F, 6H, and 6J. Removed multiple solder smear shorts from bottom of board. Board would play but had bad sound. Replaced PROM at 1M and tested.

channelmaniac · « **Reply #193 on:** December 04, 2014, 09:39:11 PM »

Model: Pac Man
Symptom: Dead. One ROM socket missing from the board.

Removed the individual pins from the missing socket and installed a new one. Erased the "Ms. Pac Man II" EPROMs and reprogrammed them with Pac Man at customer's request. Tested.

channelmaniac · « **Reply #194 on:** December 30, 2014, 06:13:05 PM »

Model: Mortal Kombat II
Symptom: Dead

Fixed bent pins on the ROM sockets on the bottom of the board. Fixed a bent power pin on UJ12 (Program ROM) and tested.

channelmaniac · « **Reply #195 on:** January 04, 2015, 05:34:31 PM »

Model: Mortal Kombat 2
Symptom: Dead

Replaced missing filter choke coil in +5v line and tested.

channelmaniac · « **Reply #196 on:** January 04, 2015, 05:36:51 PM »

Model: Mortal Kombat II
Symptom: Graphic corruption and reboot loop.

Board was a 4Mb ROM version and was missing daughterboard. Converted board to the single 8Mb revision using chips from a parts board and tested.

This conversion involves moving 4 jumpers between the program ROMs and graphics ROMs to activate address line A19, replacing the graphics ROMs, and replacing one PAL.

channelmaniac · « **Reply #197 on:** January 04, 2015, 05:37:58 PM »

Model: NBA Hangtime
Symptom: Dead

Replaced corroded battery holder and installed battery. Tested.

The boards in this series (including MK3/UMK3 and Rampage World Tour) require a good backup battery or they will appear to be dead.

channelmaniac · « **Reply #198 on:** January 04, 2015, 05:39:56 PM »

Model: Mortal Kombat 3
Symptom: Graphics corruption and ROM errors.

Board had physical damage.

Replaced several smashed SMT components: 1 capacitor, 1 coil, 1 74ABT244, and 1 74F244 IC. Patched one gouged trace on the bottom of the board. Programmed a replacement ROM for missing U129 and a replacement ROM for a bad U116. Tested.

channelmaniac · « **Reply #199 on:** January 08, 2015, 03:36:11 PM »

Model: NFL Blitz
Symptom: No video

Board would play blind and was sending a proper sync signal to the monitor.

Replaced three open surface mount resistors in the video output circuit and tested.

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Author Topic: Midway Games (Read 107409 times)