Author Topic: Midway Games (Read 104115 times)

channelmaniac · « **Reply #340 on:** November 25, 2020, 11:37:02 PM »

Model: Ms Pac Man
Symptom: Intermittent graphic corruption and reboots

Repaired the edge connector and recapped the PCB. Reflowed bad solder joints on the Sync Bus Controller to fix the reboot issue and bad solder joints on the VRAM Addresser module to fix the graphic corruption issues. Tested.

channelmaniac · « **Reply #341 on:** November 26, 2020, 11:31:25 PM »

Model: Ms Pac Man (ROM Hack Pac Man)
Symptom: Crashes / Reboots

Replaced 2 corroded sockets and cleaned the legs on 2 ROMs. Replaced damaged sockets on the Sync Bus Controller and VRAM Addresser modules. Recapped PCB and repaired burnt edge connector. Tested.

channelmaniac · « **Reply #342 on:** November 27, 2020, 09:09:50 PM »

Model: Pac Man
Symptom: Reboots

Cleaned CPU legs and recapped PCB. Tested.

channelmaniac · « **Reply #343 on:** November 27, 2020, 09:12:24 PM »

Model: Ms Pac Man (ROM Hack Pac Man)
Symptom: Crashes / Reboots

Board had solder clumped up on the edge connector.

Desoldered the edge connector and repaired burnt contacts on it. Tested to find it stuck in self-test reboot with "Memory OK." Cleaned the legs on the 6 Program ROMs and tested. Board played but the colors were off so that Ms Pac looked like a molded green wheel of cheese. Cleaned the pins on the 74LS75 in the video output circuit and retested. Recapped the PCB and retested.

channelmaniac · « **Reply #344 on:** November 28, 2020, 01:13:44 AM »

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

Game is a Ms Pac ROM hack using 2 extra ROMs and mods on the Pac Man board.

Someone had shoved the big square pins of the Sync Bus Controller and VRAM Addresser modules into the sockets on the main board, damaging them.

Cleaned legs on all 6 Program ROMs, recapped PCB, and repaired the edge connector. Game played, but Ms Pac looked like a wheel of green, moldy cheese. Cleaned dirty legs on the 74LS75 IC in the video output section and tested. Installed new sockets for the Sync Bus Controller and VRAM Addresser and installed sacrificial sockets on the pins on both modules. Reinstalled the modules and tested.

channelmaniac · « **Reply #345 on:** December 09, 2020, 12:38:20 AM »

Model: Galaxian
Symptom: Stuck in boot loop

Replaced bad ROM at position W and tested. Graphics were garbled. Replaced both character ROMs at 1H / 1J and tested. Rack sounds were off. Replaced the 2 transistors and the LM324 7T chip to fix those. Game would play but the rack sounds were incorrect at the end of the level. Found the 555 timer at 8T was installed backwards - and had factory solder. Removed chip, socketed the PCB, and reinstalled it in the correct orientation and successfully tested the rack sounds.

channelmaniac · « **Reply #346 on:** December 09, 2020, 12:42:03 AM »

Model: Ms Pac Man
Symptom: Dead, garbage on screen

Replaced bad mask ROM at 6H and tested. Recapped the audio and power sections of the PCB and retested.

channelmaniac · « **Reply #347 on:** December 10, 2020, 04:00:36 PM »

Model: Ms Pac Man
Symptom: No sound

Board had been recapped with radial caps and 1000uf were used instead of 10,000uf.

Replaced the radial caps with proper axial types. Replaced the audio amplifier IC to fix the missing audio issue. Board played but the moving characters were transparent - you could see the dots under them as they moved around the maze. Found a gouged trace causing the 6MHz signal to not make it to the 74LS75 in the video output section. Patched trace and retested.

channelmaniac · « **Reply #348 on:** December 20, 2020, 11:57:18 PM »

Model: Galaxian
Symptom: Deconvert from bootleg Pac Man

Removed several wire jumpers, reinserted multiple bent chip legs back into circuit, and patched multiple cut traces. Ran a test ROM to check memory while burning a whole ROM set - 5 program ROMs and 2 character ROMs. Installed the ROMs and tested.

channelmaniac · « **Reply #349 on:** December 26, 2020, 07:10:35 PM »

Model: Ms Pac Man
Symptom: Dead

Replaced bad ribbon cable socket on the daughterboard and put the 4 PAL chips back in the proper order (!!!!) - Tested.

channelmaniac · « **Reply #350 on:** January 05, 2021, 11:15:51 PM »

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

Game was missing the ROM at 5F

Installed missing ROM. Replaced bad 74LS139 at 5L and bad RAM at 4M. Replaced damaged sockets on the two daugtherboards and the CPU. Tested. Recapped the PCB and tested again.

channelmaniac · « **Reply #351 on:** February 03, 2021, 12:11:12 AM »

Model: Pac Man
Symptom: Garbage on screen

Did not see garbage on screen. The PCB would try to boot then die. Clocks were failing.

Replaced bad socket on the 74LS107 in the clock section. Tested. Replaced volume pot to fix static noise in audio. Retested.

channelmaniac · « **Reply #352 on:** February 14, 2021, 01:43:55 AM »

Model: WWF Wrestlemania
Symptom: 10 Beeps

10 Beeps is a sound subsystem error. The screen showed an error after a few reboots of U86 being bad. A quick logic probe check revealed U86 and U80 were not getting +5v to pin 28. Replaced open SMT inductor at L1 and L7. Tested. Reprogrammed U129 to resolve a ROM error. Tested.

channelmaniac · « **Reply #353 on:** February 14, 2021, 01:45:32 AM »

Model: WWF Wrestlemania
Symptom: RAM Error

Board was skipping boot up diagnostics. Ran diagnostics by flipping DIP 1 and found an error with the 62256 SRAM at U37. Replaced the SRAM, removed a wire jumper from DIP SW 1, switch 2, and reprogrammed U129 to resolve a ROM error message. Tested.

channelmaniac · « **Reply #354 on:** February 22, 2021, 11:36:31 PM »

Model: Ms Pac Man
Symptom: Blows fuses

Replaced shorted zener diode and tested.

channelmaniac · « **Reply #355 on:** February 23, 2021, 02:45:32 PM »

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

Replaced bad Work RAM 1 at 4R and tested.

channelmaniac · « **Reply #356 on:** February 23, 2021, 04:42:13 PM »

Model: Pac Man
Symptom: Dead. Garbage on screen

Board had a 'Six Pac' enhancement kit installed.

Board would show a '0' on the screen along with some random garbage. Checked the RAMs and they were OK. Discovered a bent pin under the Z80 Sync Bus Controller. Fixed that and tested the board.

channelmaniac · « **Reply #357 on:** April 02, 2021, 09:50:37 PM »

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

Cleaned flaking silver tarnish off Mask ROMs and from inside sockets. Tested.

channelmaniac · « **Reply #358 on:** April 02, 2021, 09:52:10 PM »

Model: Ms Pac Man
Symptom: Dead. Missing parts.

Replaced missing voltage regulator and current pass transistors. Replaced bad 10uf cap in the zener diode circuit. Replaced one 2114 RAM with a broken leg and one bad 2114 RAM. Tested.

channelmaniac · « **Reply #359 on:** June 30, 2021, 09:06:01 PM »

Galaxian

Dead. Missing daughterboard.

Removed 2 EPROMs plugged in where the daughterboard goes. Installed replacement daughterboard and tested. "RAM 3 ERROR" - Replaced a bad 2101 RAM and tested. The game played but had sprite corruption. Checked the character ROMs at 1H / 1J and found that they both were the same ROM for 1H. Burned a replacement for 1J and tested.

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Author Topic: Midway Games (Read 104115 times)