Author Topic: Midway Games (Read 102696 times)

channelmaniac · « **Reply #220 on:** March 18, 2016, 10:24:27 PM »

Model: Pac Man
Symptom: Dead

Board had been modified with a single ROM conversion.

Removed conversion and patched a cut trace. Replaced the 2200uf radial capacitor someone installed with the proper axial type. Installed a 6-Pac kit on the board and tested.

channelmaniac · « **Reply #221 on:** March 18, 2016, 10:26:01 PM »

Model: Ms. Pac Man
Symptom: Dead

Replaced a bad CPU socket on the daughterboard. Game played but had garbled sound and the sprites moved incorrectly. Replaced a bad 7489 chip to fix the sprite movement and another 7489 in the sound circuitry. Repaired a burned power connection on the board edge connector and tested.

channelmaniac · « **Reply #222 on:** March 18, 2016, 10:26:43 PM »

Model: Ms. Pac Man
Symptom: Dead

Replaced 3 missing ROMs on row 6, repaired a burned edge connector, and tested.

channelmaniac · « **Reply #223 on:** March 18, 2016, 10:36:22 PM »

Model: Ms. Pac Man
Symptom: Dead

Replaced a bad ROM, 1 2114 RAM, and replaced the ribbon cable to the daughterboard. Repaired multiple burned traces on the edge connector. Tested.

channelmaniac · « **Reply #224 on:** April 12, 2016, 09:46:34 PM »

Model: Ms Pac Man
Symptom: Dead, blows fuses.

Replaced backwards 2200uf @ 25v capacitor in the sound section. Board ran but had no sound. Replaced audio amplifier chip and tested.

channelmaniac · « **Reply #225 on:** April 16, 2016, 11:38:15 PM »

Model: Ultimate Mortal Kombat 3
Symptom: Dead

Replaced a shorted U25 and tested. Graphics ROM 132 failed tests and had its quartz window shattered. Replaced the ROM and retested game.

channelmaniac · « **Reply #226 on:** April 17, 2016, 09:04:19 PM »

Model: Mortal Kombat 4
Symptom: Dead.

All four LEDs on the board were stuck on. Tested all the crystal oscillators and looked the board over for physical damage. Patched 7 cut traces between the RAM chips on the left edge of the board and tested. Dead. Checked the program ROMs and found one corrupted. Replaced both with revision 3 code and tested. The board booted and reported one bad sound ROM. Programmed a replacement ROM and played the game.

channelmaniac · « **Reply #227 on:** April 19, 2016, 08:44:54 PM »

Model: Mortal Kombat
Symptom: U99 Failed during self test

Board had liquid spill problems.

Cleaned board then replaced a bad socket on U115 and cleaned its pins. Checked traces under and replaced chips with corroded pins at U80, U81, U82, and U85. Patched a bad trace on pin 17 between U96 and U97 to fix the U99 failure during self test. Board would not save any data to battery backed SRAM. Patched bad trace between pin 20 of U49 and pin 12 of U39. Board played but was missing speech. Recapped audio board and tested.

channelmaniac · « **Reply #228 on:** April 20, 2016, 10:38:41 PM »

Model: Super Pac Man
Symptom: Dead

Replaced bad 74LS368 at 4A and the 16XX and its socket at 4B to fix the garbled clock signal. Board would boot but was stuck at the RAM/ROM OK screen but would periodically glitch and flip upside down. Replaced a broken resistor pack at RM1 which left a DIP switch bank floating. Board would boot and play but the colors for the motion characters were wrong. Pin 12 on the 74LS298 on the video board at 4L was stuck high. Replaced the resistor pack and tested.

channelmaniac · « **Reply #229 on:** June 03, 2016, 08:13:04 PM »

Model: Bosconian
Symptom: Stuck on RAM OK

Board had attempted repair damage and 3 jumper wires on the CPU board.

Removed the 3 jumper wires and replaced all of the 24, 28, 40, and 42 pin sockets and the unencapsulated resistor packs. Patched the 4 damaged traces under one of the EPROMs on the CPU board (previous repair tech missed one!), replaced a missing board standoff, and tested.

channelmaniac · « **Reply #230 on:** June 03, 2016, 08:20:07 PM »

Model: Bosconian
Symptom: Shows QAM 4 on the screen

Board had attempted repairs done. A previous tech replaced the socket on the 51xx IC and pulled a trace, but jumpered it under the sockets with blue Kynar wire. The two 6116 SRAMs on the video board had been resocketed, but this did not fix the RAM error.

A data bus line was shorted to ground through 48 ohm resistance. Traced it back to a bad 74LS368 on the CPU board. Replaced it and tested the game. Replaced all the 24, 28, 40, and 42 pin sockets and the unencapsulated resistor packs. Retested game and noticed a thump in the audio. Recapped the audio section and retested successfully.

channelmaniac · « **Reply #231 on:** June 25, 2016, 03:16:41 PM »

Model: Ms Pac Man
Symptom: Refresh board.

Board had leaking capacitors and a burned edge connector. Recapped board (2 x 10kuf, 1 x 2200uf, 2 x 470uf, 1 x 330uf, and 1 x 10uf axial electrolytic capacitors) and repaired the edge connector with copper trace tape.

channelmaniac · « **Reply #232 on:** July 03, 2016, 07:11:24 PM »

Model: Mortal Kombat
Symptom: Static in audio

Recapped the audio board and tested

channelmaniac · « **Reply #233 on:** July 03, 2016, 07:12:46 PM »

Model: Mortal Kombat
Symptom: Dead. Stuck in reset.

Straightened several shorted pins on the EPROMs, checked the Program ROMs, and replaced a bad PLS153 logic chip at U40. Game played but had static in the audio. Recapped the audio board and retested.

channelmaniac · « **Reply #234 on:** July 09, 2016, 08:35:49 AM »

Model: Blitz 2000 Gold
Symptom: RAM Errors

Board had physical damage and was missing one RAM by the CPU.

This was a strange repair. The CPU RAM showed good, even though one was physically missing. Replaced missing RAM and jumpered 2 traces from a missing solder pad to the RAM. Board still showed video RAM errors. Reflowed lifted pins on the TMU video chip and tested.

channelmaniac · « **Reply #235 on:** July 18, 2016, 09:20:11 PM »

Model: Blitz 99
Symptom: Random video RAM errors, hangs on sound system tests, and random lockups/reboots

Replaced bad sound ROM to fix sound system issues. Reflowed U85 system controller IC to addresses lockup/reboot issues, and tested.

channelmaniac · « **Reply #236 on:** July 18, 2016, 09:21:42 PM »

Model: Ms. Pac Man
Symptom: Incorrect colors

Cleaned pins on PROM at 7F and tested. Recapped the board and replaced a broken monolithic cap at C34 on IC 4H. Tested.

channelmaniac · « **Reply #237 on:** September 05, 2016, 03:30:25 PM »

Model: Ms. Pac Man
Symptom: Dead

Someone had soldered up the contacts on the edge connector.

Removed excess solder from the edge connector and fixed several bad contacts with copper trace tape. Replaced bad ROMs at 6E and 6J and two bad 10,000uf capacitors in the power supply section. Tested.

channelmaniac · « **Reply #238 on:** September 06, 2016, 10:41:16 AM »

Model: Ms Pac Man
Symptom: Burned edge connector

Repaired the edge connector power and ground traces on the side next to the big heatsink with copper trace tape. Tested.

channelmaniac · « **Reply #239 on:** September 16, 2016, 07:43:03 PM »

Model: Cruis'N World
Symptom: Dead. Colored garbage on screen.

Reflowed custom DMA controller to restore life to game. Replaced bad 7407 IC in video output to restore missing video sync. Tested.

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Author Topic: Midway Games (Read 102696 times)