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NLG Users Repair Logs and Other Ramblings. Request your very own topic. Just ask any site staff. => Channelmaniac's Arcadecomponents' Old School Repair Logs => Topic started by: channelmaniac on May 04, 2014, 05:20:45 PM

Title: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:20:45 PM
Model: Kangaroo
Symptom: Monitor only shows a white screen

This was an old WG 4600 series monitor. Replaced a shorted zener diode and blanking transistor on the input daughterboard. While the board was out a cap kit was installed and all cracked solder joints were fixed.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:21:00 PM
Model: Pit Fighter
Symptom: Game controls not working

Replaced bad 74LS244 ICs at locations 70B and 75B. Tested board.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:21:13 PM
Model: Pit Fighter
Symptom: Garbled graphics

Swapped IC S30 with a parts board to fix. Burned a replacement GAL for the parts board.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:21:29 PM
Model: Pit Fighter
Symptom: No video output

Traced the missing video signal back to the output latches. Signal was on the input side but not crossing the IC. The clock signal was missing on the latches. Replaced the GAL at 65D to fix.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:21:44 PM
Model: Pit Fighter
Symptom: Loses most sounds after heating up

Most audio signals disappeared after playing the game for about 10 minutes. Cooling spray had no effect. The audio signals would come & go. Sometimes they would work but most of the time they wouldn't. IRQ lines were going dead when the sounds disappeared. Replaced the 6502A CPU on the sound board to fix.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:22:01 PM
Model: Any old Atari game with the Big Blue caps in the bottom of the cabinet.
Symptoms: Locks up, reboots randomly, humming in speaker, and more.

The big caps in the bottom of the cabinet are notorious problem parts and should be replaced if you aren't sure they have already been replaced.

While checking the power supply be sure to also check the audio/regulator boards as they are bad about having cracked solder joints.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:22:12 PM
Model: Pole Position II
Symptom: runs but has garbled video

Put the game in test mode and found that the video RAM was bad. Replaced 2 2148 SRAM chips and had fun playing the game.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:22:22 PM
Model: Road Riot 4WD
Symptom: No sound

Volume was set to zero. This model is strange in that you must go into the electronic setup and choose the volume setting. There is no volume control.

If the EEPROM used to store the settings is bad then this setting will not be saved. The sympom of this is if you set the volume and other settings and they aren't retained if the board is powered off.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:22:37 PM
Model: Road Riot 4WD
Symptom: No sound and corrupt graphics

The MOB (Motion OBjects) checksum test failed. The EPROMs all had a checksum of 0000 meaning they weren't being accessed. The motion objects on the screen were missing.

Replaced bad GAL at board location 11S (part # 136089-1009) to fix graphics problem. Replaced missing GAL at location 6C (part # 136089-2011) with a programmed PALCE device (functional equivalent once programmed) in an attempt to fix sound. Sound worked but would either be at maximum volume or at zero. The settings would not save. Replaced bad 2816 EEPROM IC to fix the problem with saving the settings.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:22:53 PM
Model: Several different Atari games
Symptom: Bad GAL chips

The GAL chips on the Atari arcade games are set with their protection bits on. This precludes reading a GAL chip from a working board to fix a dead one.

Replacement code for burning your own GAL or PALCE chips can be downloaded from the Atari GALlery web site for the following games:

    Guardians of the 'Hood
    Hydra
    Moto Frenzy
    Pit Fighter
    Relief Pitcher
    Road Riot 4WD
    Shuuz
    Skull & Crossbones
    ThunderJaws
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:23:10 PM
Model: Road Riot 4WD
Symptom: Corrupt Graphics

The title screen on the game was skewed for the top half of the upper set of words ("ROAD RIOT") and during the game the sides of the road were randomly split and moved.

The custom IC at board location J18 (Part # 137419-104) had a broken leg. Swapped out the IC from a parts board to fix.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:23:41 PM
Model: Shuuz
Symptom: Garbage on screen.

A bunch of numbers flashed on the screen repeatedly and the game would reset. It was "stuck in watchdog: with a message at the bottom saying "TOO MANY EETRIES"

Tested the EPROMs and SRAM ICs. Replaced 1 bad SRAM but was still stuck in watchdog.

The MAME .c driver showed the game would initialize the EEPROM as the first thing. Checked the 28C16 with a logic probe. The chip enable, output enable, and read lines were OK. Pulled the chip and tried reading it in my EPROM programmer. Every time it read it gave a different data set out, in other words a different checksum showed on the programmer each time.

Replaced the 28C16 and the game fired right up. Turns out "TOO MANY EETRIES" is an error message on a core dump for the game.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:23:54 PM
Model: Tetris
Symptom: Stuck in Watchdog

Game had no display. Checking the address and data lines with a logic probe revealed that the game was stuck in watchdog - it was constantly resetting.

Replaced a bad 2804 EEPROM IC and reinitialized the game's settings.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:24:09 PM
Model: Area 51
Symptom: Dead

Game board was stuck in watchdog.

Board had been worked on before and was tagged as "unrepairable". One chip that was replaced not soldered well at all. It was like they used silver solder on it and it was VERY difficult to resolder. Resoldered that FPGA chip then the CPU and DSP chips.

Cleaned the PLCC socket on the IC that reads the gun inputs and replaced a bad 14.31818 MHz crystal oscillator.

Replaced the missing hard drive with a 2Gb Compact Flash card and adapter then tested the game.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:24:24 PM
Model: Centipede
Symptom: Garbage on screen. Enemies move erratically

Replaced bad RAM at M5. Logic probe showed erratic signals on DO2 (Data Output 2)
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:24:36 PM
Model: Centipede
Symptom: Garbage on screen, reboots at random

Fired up test mode and received 9 beeps. Replaced the bad RAM at N7 and tested. Garbage was gone with the exception of horizontal lines on the screen. Cleaned the character ROM legs to fix the lines. Cleaned the program ROM legs to fix the rebooting issue then tested board.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:24:51 PM
Model: Centipede
Symptom: Dead

Replaced a missing clock crystal and tested. Board came up with a white screen and CPU stuck trying to boot. Cleaned the legs on the program ROMs then the board would try to come up and had some random characters on the screen. Found where something scraped across the board, dragging some solder with it and shorting 2 traces. Removed short and tested the game. Replaced 2 broken transistors and retested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:25:05 PM
Model: Centipede
Symptom: Board hacked

The MC14584 chips buffering the trackball inputs had been modified. Removed the 2 chips, 6 tacked on resistors, and 6 tacked on capacitors that were sticking out above the board. Removed 4 3.9k ohm resistors that were changed on the board. Installed 4 10k ohm resistors and 2 new MC14584 chips. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:25:17 PM
Model: Area 51
Symptom: Red/Purple scrambled screen

Board had no output on sync. Replaced a bad 7406 at location C20 to fix sync. A 10 ohm SMT resistor at location R118 was out. This caused the board to have no green output. Replaced the resistor and tested the board.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:25:30 PM
Model: Dig Dug
Symptom: ROM 1 Error

Checked the ROM at 6L and it had a bad checksum. Replaced ROM and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:25:45 PM
Model: Centipede:
Symptom: Screen full of lines

The game powered up and the screen looked like an Atari 2600 without a cartridge installed. Checked the clock circuit and replaced bad 74LS163 ICs at M2 and P3. Board powered up but the screen was partially garbled. Replaced bad RAMs at L7, M7, and N7. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:25:57 PM
Model: Centipede
Symptom: Stuck in watchdog

Cleaned the pins on the CPU and ROMs... Replaced the sockets and cleaned the pins on the POKEY and NVRAM chips. Tested board.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:26:09 PM
Model: Centipede
Symptom: Dead. Nothing on screen.

Board was stuck in watchdog and had no output to the screen. Cleaned the legs of the CPU, POKEY, and ER2055 EAROM. Board would give a single beep when put in test mode now. Replaced the 2114 RAMs at F2 and H2. Board would then play blind. Board was missing the /HBLANK signal. Replaced bad 74LS107 at L4. Board then had video output but it was slightly garbled. Replaced the RAM at M5 then tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:26:21 PM
Model: Area 51/Max Force combo
Symptom: Player 1 gun not registering hits

Board had attempted repair damage.

Replaced bad surface mount 74LS14 on the gun inputs. Patched damaged traces, and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:26:33 PM
Model: Centipede
Symptom: Player 2 stuck to the right side of the screen

Very odd symptom. Player 1 and Player 2 use the same controls and input circuitry. Replaced bad 74LS257 at D9.

Unsure why it was working perfect for player 1 and not player two! The chip showed bad on all 4 outputs on a BK 560A IC tester, but still worked fine for player 1. Head scratcher for sure!
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:26:57 PM
Model: Centipede
Symptom: Dead. Solid white screen.

Board was dead. Data bus line D1 was stuck low on the far side of the 74LS245 latch from the CPU. Replaced 74LS373 at J5 and would play blind but the sounds were off. Replaced bad POKEY to fix audio issues. Replaced bad 74LS289 Bipolar RAM at C8 to fix white screen issue. Board would play, but the archer would not move fully to the left and centipede would get stuck on the left 1/4 of the screen. The board would not pass self tests and would continuously beep. Used a Fluke 9010A to test the board and found RAM range 0500-05FF had a stuck bit. Replaced bad 2101 RAM at K5 and tested board.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:27:10 PM
Model: Centipede
Symptom: Dead. Black Screen

Board would not read the RAM or ROMs with the Fluke 9010A. Found smeared solder short under ROM at J1. Fixed solder short and replaced ICs B1, C1, F2, H2, J2, J4, and P6 that were damaged by the solder short. Board was still dead, but the CPU was able to read and write to all of the RAMs and read the ROMs properly. Discovered board was missing VSYNC signal. Traced it back and discovered a 74LS163 at IC P4 instead of the proper 82S129 PROM. Programmed a replacement PROM and installed it. Tested board.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:27:26 PM
Model: Centipede
Symptom: Would not coin up with the correct amount

Replaced bad DIP switch and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:27:41 PM
Model: Centipede
Symptom: Dead

Replaced bad ROM socket at J1. Reseated the other 3 ROMs. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:27:55 PM
Model: Centipede
Symptom: Stuck in Reset

Board would boot to the game but constantly reset. Replaced bad RAM at H2 and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:28:17 PM
Model: Shuuz
Symptom: Excessive EEROM Retries error. Missing motion objects.

Replaced 28C16 chip. Replaced missing GAL chip at 97N with one programmed with code from the Atari GALery. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:28:30 PM
Model: Area 51/Max Force Combo
Symptom: Will not boot.

Cleaned soda spill from board. Replaced IDE to Compact Flash Adapter. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 04, 2014, 05:28:44 PM
Model: Centipede
Symptom: Dead. No video.

Board had CPU and ROM activity but no horizontal or vertical sync or blanking signals. Replaced dead 74LS163 at N2 and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on June 03, 2014, 06:00:34 PM
Model: Dig Dug
Symptom: No sound

Replaced the LM324 op amp as it was running hot. Replaced a dead 74LS174 at location 2M/N and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on September 20, 2014, 10:04:31 PM
Model: Rolling Thunder
Symptom: No red or green on screen, only blue.

Replaced bad PROM at location 3R. Removed short on pin 4 of IC 3U to fix a blue shading issue. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on January 20, 2016, 09:43:29 PM
Model: Toobin'
Symptom: Missing colors on screen

Replaced a physically broken custom resistor pack in the video output section with one from a donor board and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on September 02, 2016, 07:16:31 PM
Model: Dragon Spirit
Symptom: Garbage on screen

Board would play, but the screen was scrambled.

Replaced bad SRAM at L5 on the daughterboard and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on October 16, 2016, 09:01:41 PM
Model: Tetris
Symptom: Dead. Garbage on screen

Replaced bad 6502A CPU and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on January 10, 2017, 06:53:05 PM
Model: War: Final Assault
Symptom: Burning components

Replaced 2 shorted and burning 10uf @ 16v surface mount Tantalum capacitors and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on April 09, 2017, 07:05:16 PM
Model: Centipede
Symptom: Dead

Replaced missing 12.096MHz crystal and straightened bent pins on 2 ICs. Board would boot to garbage. Replaced a bad 6502 CPU and tested game.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 22, 2017, 10:09:15 PM
Model: Centipede
Symptom: Dead

Cleaned corroded legs on the Program ROMs, Video ROMs, CPU, and POKEY chips. Tested. Repaired a burnt edge connector and retested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on August 28, 2017, 05:45:22 PM
Model: Sprint II
Symptom: Dead. Garbage on screen.

Repaired broken leg on program ROM and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on April 28, 2018, 03:59:02 PM
Model: Centipede
Symptom: Dead

Replaced broken 12.096MHz crystal and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on April 28, 2018, 03:59:45 PM
Model: Centipede
Symptom: AAA on lower screen

Received 7 beeps in test mode indicating bad RAM at M7. Replaced the 2101A RAM at M7 and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on April 28, 2018, 04:01:14 PM
Model: Centipede
Symptom: No sync

Board had no horizontal sync. Traced back the missing signals to the 74LS74 at 3M. Pin 1 was stuck low. Traced that back to the other half of 3M. Replaced the IC at 3M and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on April 28, 2018, 04:02:15 PM
Model: Centipede
Symptom: Damaged DIP switches and a burned edge connector. Otherwise, untested.

Replaced the broken bank of 4 DIP switches and repaired the burned edge connector trace with copper tape. Tested board.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on June 03, 2018, 07:18:26 PM
Model: Centipede
Symptom: Tearing graphics and sync issues

Replaced bad 2102A RAM at K5 to fix graphics RAM error beep. Replaced 74LS04 IC and bad socket with a proper 74S04 and a new socket. Replaced crystal as it had loose legs. Board played with incorrect colors and no sound. Replaced bad LM324 to restore sound and the 74S289 color RAM to fix the screen color issue. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on June 22, 2018, 04:22:15 PM
Model: Millipede
Symptom: Dead. Garbage on screen

Game had 2 dead GTE 2114 RAMs. Replaced them and it still wouldn't boot. ROMs checked OK. Looked under the CPU and POKEY sockets and found 2 shorted traces under one POKEY caused by someone with a careless screwdriver lifting chips. Removed the solder short with a hot iron and a bit of liquid rosin flux and tested the game.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on September 09, 2018, 08:43:14 PM
Model: Dig Dug
Symptom: Dead. Missing parts.

Replaced the three missing CPUs and tested. Reseated the 08xx IC on CPU3 and played a game to test the board.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on December 21, 2018, 03:54:43 PM
Model: Gauntlet Dark Legacy
Symptom: Will not boot unless edge connector is pulled up hard.

Cleaned burned edge connector contacts on the +5v line and repaired them with copper trace tape. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on January 06, 2019, 12:52:57 AM
Model: Centipede
Symptom: Enemy dive bombs immediately killing players

Self test gave 4 beeps. The RAM was good at K5 and signals were all present so it was a process of elimination to find the 74LS157 @ P5 was bad. Replaced IC and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on January 06, 2019, 12:55:38 AM
Model: Dig Dug
Symptom: Burned edge connector

Repaired the burned edge connector with copper trace tape. Tested the game.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on February 10, 2019, 06:58:07 PM
Model: Centipede
Symptom: Dead

Installed a missing PROM at P4. Game booted to a white screen. Cleaned the legs on the character ROMs and board would boot but was stuck in watchdog. Replaced bad CPU socket and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on February 10, 2019, 08:36:29 PM
Model: Centipede
Symptom: Moves left/right but not up/down

Replaced 74LS74 at D11 that had a stuck output. Reset DIPs and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on February 10, 2019, 10:24:11 PM
Model: Centipede
Symptom: Dead. Multiple chips missing.

Replaced a missing 14585 at E/F-11, missing 74LS157 at D/E-11, missing 74157 at D8, and a bad 7489 RAM in the video output section at C8. Reset DIPs and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on April 18, 2019, 03:09:13 PM
Model: Dig Dug
Symptom: No sync

Replaced bad 74LS368 and 74LS00 in the sync circuit. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on May 17, 2019, 09:29:44 PM
Model: Dig Dug
Symptom: Dead. Missing chips.

Board was missing a 2114 RAM and a 2148-55 RAM

Replaced missing RAM and tested. Board threw a 2L error and had sparkling garbage on the screen. Removed a solder splash short from between a 2 chip legs and under the chip. This fixed the sparkling but every other RAM tested bad one by one so all 6 of the 2114 RAMs were replaced. Tested and burned in the board for several hours.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on March 09, 2020, 06:01:23 PM
Model: Centipede
Symptom: Stuck colors on output. Missing text and non-motion characters.

Replaced a bad 74LS42 at location H3 that had a stuck output on pin 6. This caused the /COLORAM signal to be stuck high and the colors to never change on screen.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on April 10, 2020, 11:57:45 PM
Model: Skull & Crossbones
Symptom: Garbage on screen. Fails RAM tests

Resoldered a broken resistor back into place feeding +5v to the CS2 line on the playfield RAMs. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on November 27, 2020, 03:14:56 PM
Model: Dig Dug
Symptom: Dead

Replaced missing crystal and tested. Board was stuck in a reboot loop. Reseated an auxiliary Z80 CPU that wasn't properly inserted in the socket. Board would then boot but had a graphic corruption issue. Fixed bent leg on a ROM chip and reinserted it into the PCB. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on November 27, 2020, 03:58:40 PM
Model: Dig Dug
Symptom: Dead, garbage on screen

Replaced missing 00xx custom IC and fixed 5 solder smear shorts on the bottom of the PCB. Set DIPs and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on December 09, 2020, 07:51:19 PM
Model: Centipede
Symptoms: Dead

Replaced broken crystal and dead CPU. Game played but was missing the red eyes on the player and centipede, spider, and was also missing the shots. Replaced bad 74S74 at E9. Screen suddenly had garbage all over. Replaced the bipolar RAMs at A6 and B6.

This was an odd repair in that the RAM was bad, but so was the latch that gated their outputs and the combination gave a good screen, just missing red from motion sprites.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on December 22, 2020, 01:20:54 AM
Model: Dig Dug
Symptom: Dead. Random colored lines on the screen and no sync.

Clock was coming and going according to my logic probe... and the divided clocks out of the 07xx chips were skipping around badly. Swapped out the 74S04 and 74LS107 to no effect. Pulled out the oscilloscope and saw the 18.432MHz frequency was actually running at 3x overtone at 55.296MHz. Replaced an open 100pf mica capacitor in the clock crystal circuit and successfully tested the game.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on December 22, 2020, 06:04:38 PM
Model: Relief Pitcher
Symptom: No audio

Cleaned edge connector and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on December 29, 2020, 01:33:29 AM
Model: Maximum Force
Symptom: Error on screen

Error was a hard drive problem. Burned the MAME .chd to a Compact Flash card and tested. Reprogrammed the 4 ROMs on the PCB and burned the Max Force / Area 51 combo and converted the PCB. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on March 19, 2021, 08:33:09 PM
Model: Dig Dug
Symptom: Doubles of sprites

Replaced a bad 74LS283 IC and tested. Video output is dull looking - muted colors. Found attempted repairs to the video output section and shorts between resistors on the red and green outputs. Removed jumpers, cleaned up solder splashes, and jumpered 2 damaged traces to fix the video output. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on March 19, 2021, 09:13:45 PM
Model: Dig Dug
Symptom: Dead. Garbage on screen.
Missing the main Z80A CPU

Installed a Z80A CPU. Replaced dead -101 and -104 program ROMs. Game would try to boot but had RAM 0L errors. Tracked it down to a crashing CPU with the /NMI pin running crazy. Fixed a broken pin 15 on the 06xx custom and the board booted but had no background graphics. Replaced a stuck 74LS259 and LS257, a dead -115 EPROM, and a dead -113 PROM. Tested. No audio. Replaced bad LM324 Op Amp and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on March 24, 2021, 08:53:12 PM
Model: Dig Dug
Symptom: Dead. Garbage on screen

"Multimeter leads shorted while checking NVRAM" (Ouch. The NVRAM power is +5v and -29v DC)

This board had some serious issues. Started by checking for shorted / overly hot chips. Replaced the -114 ROM. Replaced all 6 2114 RAMs, both 2149 RAMs and the 6116 SRAM plus the 74LS245 feeding it. Board would try to boot but fail. Fixed 2 broken pins on the 08xx on CPU 3 and replaced its socket. Replaced bad CPU socket and 74LS139 decoder for CPU 1. Board would boot but with  ROM errors. Replaced shorted 74LS374 on the NVRAM circuit, 2x shorted 74LS273 in the background video circuit, and the board would boot with graphic corruption - missing colors on the Dig Dug graphic and missing white on sprites. Replaced the -111 PROM to fix that. Tested successfully. Checked the remaining NVRAM circuit and replaced a shorted 74LS175 and 74LS244 chip and for good measure, the ER2055 NVRAM. Retested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on April 07, 2021, 08:19:51 PM
Model: Centipede
Symptom: Dead. Stuck in reset.

Cleaned the legs on the CPU, POKEY, and Program ROMs. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on January 07, 2022, 08:36:56 PM
Model: Centipede
Symptom: Dead

Replaced missing crystal. Board now has clocks but will not boot. Cleaned the program ROM legs and tested. Board played but had flickering sprite glitches. Cleaned the legs on the two character ROMs and retested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on February 20, 2022, 09:30:33 PM
Model: Rolling Thunder 2
Symptom: No audio

Replaced bad LA4460 sound amp IC and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on March 23, 2022, 02:42:20 PM
Model: Centipede
Symptom: Dead, rolling & flashing garbage on screen.

Replaced 2 bad 2114 RAM chips and tested. Board would be stuck in watchdog and screen rolling for the first 10 seconds before stabilizing. Replaced bad 74LS163 clock divider at N3 and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on March 07, 2023, 02:19:55 AM
Model: Area 51: Site 4
Symptom: Dead

Replaced 2 cracked capacitors on the CPU board. Replaced failed hard drive. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on March 10, 2023, 10:35:22 PM
Model: Area 51 / Maximum Force Duo
Symptom: Graphics corruption

Bank 1 /UCAS signal missing. Replaced bad GAL chip, reflowed CPU, reflowed DSP, recapped PCB, and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on September 20, 2023, 10:02:33 AM
Model: Shuuz
Symptom: Dead

CPU's /RESET signal was stuck low. /VBLANK was missing from the circuit. /HSYNC and /VSYNC signals were also missing. Found 1 GAL chip running hot and one that blistered a finger. Replaced the 2 GAL chips and the missing signals returned. The CPU was stuck in Watchdog. Replaced 2 more GALs that had missing outputs and CPU was still stuck in Watchdog. Replaced the Addressing GAL to finish the repair.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on October 30, 2023, 10:51:55 PM
Model: Tetris
Symptom: Garbage on screen

Replaced 1 transistor in /RESET circuit. Booted to Color RAM Failure. Replaced 1 74LS138 to fix stuck R/W signal to the Color RAM. Replaced 11 missing .1uf caps on the control inputs. Tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on October 30, 2023, 10:53:57 PM
Model: Tetris
Symptom: Dead

Unit was missing 6502A CPU.

Replaced missing 6502A CPU. Board booted to Work RAM Error. Replaced bad 74LS257 which had 2 stuck outputs. Board booted to Color RAM Error. Replaced a bad 74LS257 with stuck outputs and a bad 74LS138 chip to fix stuck R/W signal. Tested. Board had a stuck input. Replaced missing 470 ohm resistor and tested.
Title: Re: Atari Games (Arcade)
Post by: channelmaniac on October 30, 2023, 10:55:17 PM
Model: Tetris
Symptom: Will not save settings

Replaced bad Test switch as board would not go into test mode. Replaced 2804 EEPROM. Initialized the EEPROM and tested changing settings.
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