Problem Page

This is the "Blast from the Past" problem page. As we all well know the biggest stress of collecting video arcade games is when they go wrong, well that and finding somewhere to put the things. This page is designed to try and help out those of us who don't mind getting out the soldering iron and flicking some solder.

This page contains over 130 repair logs covering most of the popular game boards. These repair logs describe specific board faults and the action that was taken to repair them. Although many different board faults could show the same symptoms, these logs give a good pointer to start with and may fix your board completely.

Obviously not all game boards and problems are listed, but by reading through the many repair logs, problems with other or similar game boards might be of use.

I would like to take this opportunity to say a big thank you to Peter Fyfe who has provided this page with a wealth of information to get things started. Please feel free to email me your own repair logs so this page can expand and become something really useful for all of us.

If you do find this page useful please let others know!

WARNING! - Please remember none of the contributors to this page can be held responsible if you fry your board or yourself !


Alca Meteor (Taito)

ProblemSolution
Bad RAM 3 error reported at power on. Bad RAM's @ 5E & 4F.
Poor sync. Bad output on pin 6 of 74LS08 @ 6H. Replacing IC fixed the problem.
No starfield. Pin 15 @ 2B broken. Repair leg.

Amidar (Konami) - Scramble conversion

ProblemSolution
Garbage on screen. Game keeps resetting. All outputs of 74LS161 @ 7L stuck low. Replacing IC fixed the problem.

Audio/Regulator II Board (Atari)

ProblemSolution
The board is incapabled of suppling adequate current on the +5V output. The output is fine with no load but when a load is attached the output collapses. Faulty 2N3055 transistor. Replacing this transistor cured the problem.

Bank Panic (Sega)

ProblemSolution
Excess scratchy noise Replace capacitors C85, C88 and C89.

Bomb Jack (Tehkan)

ProblemSolution
Bombs shown as red blocks with "M" in the middle of the blocks. Some platforms missing. No output from pin 2 of 74LS273 @ 5L on the top board. Replacing the IC did not cure the problem completely. There was also some poor sockets on the top board at locations 8E, 8H & 8K. These were replaced and the game operated normally.
Excess hum/noise through the speaker. Some sounds missing. All outputs of sound generator AY-3-8910 @ 3/4D stuck low. All I/O pins stuck high. Replacing IC cured the sound problems.
No video. No output from 74LS74 @ 3T on the bottom board. Replacing the IC fixed the problem.
Game would not progress past self test screen. Replace Z80 @ 3K on main board.
Characters moving in the bottom half of the screen creates a mirror image (with lines missing) in the top half of the screen. All outputs of 74LS86 @ 5A stuck low. Replacing this IC fixed the problem.
No sound. Replace audio amp M51516L.
Lines across title in attract mode. Motion objects have protruding lines. Bad output on 74LS174 @ 7A on the top board. Replacing this IC cured the problem.
Double vision. 2 mazes side by side. Bad output on 74LS86 @ 2N on the bottom board. Replacing the IC cured the problem.

Bosconian (Namco)

ProblemSolution
Game will not initiate self test. Bad EPROM's on top board.
Garbage on screen. Stationary blocks on screen. Bad EPROMs. A new set of EPROMs fixed the problem.
Garbage on screen. Random blocks on screen. Can make out "RAM 4L" and "RAM 4H" in the garbage. Bad 6116 RAMs @ 1E and 1H on the bottom board. Replacing the RAMs started the game.
Incorrect colours. Bad PROM @ 4M (labeled BOS-1). Blow a new PROM to correct colours.
Block on right hand side of the screen is blank during self test. Usually combination of running shapes/letters/numbers. Mirror image of RAM 2L displayed during self test. Bad 6116 RAM @ 1E on the bottom board. Replacing the IC fixed the problem.
Game won't pass self test. Reports RAM OK but then resets. Bad PROM @ 2D (labeled BOS-3). Blow a new PROM to cure problem.
Game plays OK but the picture is faint and there is a lot of shadows on text. Video ground connection (pin 5 on Molex connector) not making a good contact. A wire add between pin 5 and ground fixed the problem.
Game won't accept credits. Pin 32 of custom 51xx IC @ 4H (top board) stuck low. Further investigation found a cut track between this pin and resistor pack RM10, with a 1k W resistor bridging the gap. The resistor was removed and the track repaired which led to the problem below.
Game racks up credits at a rate of about 2 per second. Pin 32 of custom 51xx IC @ 4H (top board) oscillating. This IC was deemed as faulty. Replacing the IC cured the problem.
No sound. Broken track between audio amp speaker output and the edge connector. Repairing the track fixed the problem.

Burnin' Rubber (Data East)

ProblemSolution
Text OK. When track appears it is covered by a dark band which comes and goes as the attract mode progresses. Pins 8 & 9 of 74LS74 @ 11B on the bottom board stuck low and high respectively. Relacing IC fixes the problem.
No sound. 6502 processor @ 2B on the top board faulty. Replacing the IC fixed the problem.

Commando (Capcom)

ProblemSolution
No motion objects. Bad output on pins 11 & 12 of 2114 @1A on bottom board (85605-B-1). Replacing the IC fixes the problem.

Galaxians (Namco)

ProblemSolution
Solid colour horizontal lines across screen. Bad sockets @ 1H and 1K. Replacing the sockets cured the problem.

Golden Axe (Sega)

ProblemSolution
Scrambled text. Bad IC @ IC18 on the daughterboard. Replace with a known good IC fixed the problem.

Defender (Williams)

ProblemSolution
Blank bands across screen. Open track between pin4 of 6M and pin 4 of 6N (on CPU board). Repairing the track fixed the problem.
Blank screen. H/V sync present but no colours. Both outputs of 74LS20 @ 3S (CPU board) stuck low. Replacing IC fixed the problem.
Rug pattern incorrect. Instead of being a random pattern, it is a very uniform horizontal line pattern. Keeps repeating. Bad output on pin 5 of 7474@6E (CPU board). Replacing the IC solved the problem.
Blank screen. All 4 LED's on ROM board are illuminated and stay illuminated. Faulty 7474 @ 6D on CPU board. Replacing the IC fixed the problem.
Vertical colour bands across screen. No output from 74LS74 @ 6E. Replacing the IC fixed the problem.
Different crap on screen each time the boards were powered up. From blank screen to white lines/dots. No output from pins 2 and 4 of 7404 @ IC19 on ROM board. Replacing the IC fixed the problem.
Rug test pattern wrong colour. When text should appear the screen goes blank. Bad output on 74165 @ 5J (CPU board). Replacing the IC fixed the problem.
Each time the the boards were powered up it would get to a different part of the self test. Sometimes you would simply get garbage. Poor solder joints on the connector that the ROM board plugs into on the CPU board. Re-flowing the solder joints cured the problem.
Rug test incorrect. Instead of the rug being one complete screen it looks like it was broken into blocks/slabs. Instead of single line scrolling down the rug (refresh type idea) the block/slab scrolls down the screen. LED's and 4 illuminated on the ROM board. No output from 74LS153 @ 3F (next to video decode 3 ROM on CPU board). Replacing the IC cured the problem.
Rug test pattern wrong colour. When text should appear the screen goes blank. Pin 12 of 74LS257 @ 2J stuck high. Replacing the IC cured the problem.
No sound. Speaker "pop" at switch on is present. Faulty 6808 @ IC9 on sound board. Replacing the IC fixed the problem.
No sound. Speaker "pop" at switch on is present. All data pins on 6808 were floating. Problem traced back to a faulty 6810 @ IC11 on sound board. Replacing the IC fixed the problem.
Complete blank screen. All 4 LED's on ROM board stay constant illuminated. The reset was constantly low. If it was manually over-ridden then the game would play as normal. The problem was traced to R2 going high resistance. It should be 22K but was reading 41K. Replacing the resistor fixed the problem.
After self test the game gives "INITIAL TESTS OK" message. First message after that should be "01 0000 COIN". The message I got was "01 ???? COIN". Faulty CMOS RAM @ 1I on CPU board. Replacing the IC fixed the problem.
Game would do the rug test then come up with some yellow vertical lines every inch or so and then reset to the rug test. Pin 14 of RAM @ 1M was not making contact with the socket. The leg was corroded. Replacing the RAM and the socket cured the problem.
When the sound board was plugged in the game failed to boot. It was noticed that the +12V output was only reading +5.5V. The sound EPROM was inserted the wrong way round.

Hunchback (Century Electronics) - Scramble conversion

ProblemSolution
Missing sounds. All outputs of AY-3-8910 @ 3/4C stuck low. Replacing IC solved the problem.
No sound. Z80 @ 3/4G had broken socket. RD/WR signal not being connected to PCB. Also broken track between pin 11 of 74LS00 @ 5H and pin 19 of 74LS245 @ 5G. The socket was replaced and the track repaired and the game operated normally.

Hyper Sports (Konami)

ProblemSolution
Some double vision. Nothing stable (text or objects). Bad SRAM @ 6H (PWB A). Replacing the SRAM fixed the problem.
Motion object (man) missing lines. Jailbar effect. All outputs of 74LS163 @ B18 (PWB A) stuck high. Replacing this IC cured the problem.

Juno First (Konami)

ProblemSolution
No sound. Audio amp faulty. Replaced amplifier to cure problem.
Intermittent sound. Faulty volume pot. Replace pot.
Characters on second wave (fireball things that follow you) appear as blocks. Bad EPROM @ 7E on the top board. Replace with a known good EPROM.

Lunar Rescue (Taito) - 3 board Space Invaders conversion

ProblemSolution
Game will not sync properly. Horizontal sync OK but there is no vertical sync. Get double picture at best. Pin 14 of 74161 @ location 6 of bottom board stuck high. Replace IC to give the problem below.
Game will still not sync properly. Vertical sync still faulty. Pin 6 of 74S04 @ location 1 was stuck low. Replacing this IC cured the problem.
Horizontal bars, one at top and one in the middle, flash across screen. Seem not to be solid but made up of discrete rectangles (|||||||||||||). Broken pins on PROMs @ locations 1 & 2 on middle board. Repair legs and the game works OK.
1P fire button doesn't work. Pin 8 of 7404 @ location 11 on top board stuck low. Replacing the IC fixed the problem.

Mexico '86 (Micro Research)

ProblemSolution
Graphics OK but characters will not kick/tackle. Combination of various shorted pins on the back of the PCB and a dirty edge connector. Cleaning the edge connector and removing the shorts cured the problem.
Half of the sounds were missing. The output of 1458 (near volume pot) was stuck high. Replacing the IC brought all sounds back.

Missile Command (Atari)

ProblemSolution
No vertical sync. Bad output on 74LS08 @ J6. Replacing the IC cured the problem.
Flashing green/yellow screen. Bad output on 74LS74 @ C8. Replacing the IC cured the problem.
Entire screen blue. Bad output on 74LS08 @ J6. Replacing the IC cured the problem.
Faulty sound explosions. Broken capacitor C70. Replace cap.

Mr. Do (Universal)

ProblemSolution
No motion objects in maze. 82S123 PROM @ 10J faulty. Re-blow a new PROM fixes the problem.
Motion objects are not a single character but are displayed as a column of characters. Bad output on pins 4 and 7 of 74LS157 @ G9. Replacng the IC cured the problem.
Motion objects are missing lines. Jailbar effect. Bad outputs on 74LS244 @ 5E. Replacing the IC fixed the problem.
Background colours incorrect. Outputs of 2732 EPROM @ 8N stuck high due to a faulty 74LS273 @ N9. Replacing the IC @ N9 cured the problem.
Mr Do not aligned with the maze. He is about 6mm above where he should be. Characters not correct colour. Bad 6148 SRAM @ A6. Replacing this chip fixed the problem.
No character in maze. Can see number of lives displayed in bottom left of screen. Game plays invisible. Bad 82S123 PROM @ either J10 or E10.

Mr. Do's Castle (Universal)

ProblemSolution
Colours running through title screen. Pins 6 and 7 of 74LS139 @ K2 stuck high. Replacing IC cured problem.
No video. Crystal XL1 not oscillating. 74LS04 @ S3/4 faulty. Replacing this IC cured the problem.
Motion objects missing lines (almost like jailbar effect) and some blocky images at bottom left corner of screen. All outputs of 74LS283 @ L6 stuck high/floating. Replacing IC fixed the problem.
Mr Do will not move right. Broken track between edge connector and resistor pack RM4. Repairing the track fixed the problem.

Mr. Du (Mr. Do bootleg)

ProblemSolution
Spurious lines on screen. Bad output on 74LS86 @ T5. Replacing the IC fixed the problem.
Screen promenantly red. All outputs of PROM @ U2 stuck high. Blowing a new PROM cured the problem.
No characters in maze. Legs of PROMs @ E10 & J10 are very rusted. A new set of PROMs fixed the problem.
Blank area at top and bottom of maze are red instead of black. Title screen red also. Output of pin 5 of 74LS151@ P10 floating. Replacing IC cured the problem.

Mrs Pacman (Midway)

ProblemSolution
Characters appear blocky. Blocks for eyes to their feet. Resistor pack RM2 intermittent. Remove and replace RM2.
Characters all at the bottom of the screen. Only moving horizontally. Bad output on 74LS139 @ 4C. Replacing IC fixed the problem.
Screen completely yellow. Bad EPROM @ 4A. Blow a new EPROM to fix problem.
Game will not initialise. 100pF capacitor missing from 74LS74 @ 8C (top board) between pins 7 & 11. Adding cap solved the problem.
Red line above text. Specifically at top of screen. Bad PROM @ 7F (top board). New PROM fixed problem.
Running light marquee on attract mode made up of of the number 5. Bad EPROM @ 5H. New EPROM fixed the problem.
Ms Pacman is actually a cross between Pacman & Ms Pacman. Bad EPROM @ 5J. New EPROM returned Ms Pacman back to her normal self.

Pacland (Namco)

  • In general, SRAM @ 10R & 10S are used for the landscapes.

    • ProblemSolution
    Game will not initialise. Bad custom IC @ 3/4/5F. A replacement custom IC solved the problem.
    Blocky, jumpy graphics. Bad RAM @ 9R. A new RAM fixed the problem.
    Bands of horizontal lines on screen. Affects landscapes only (not houses or pacman). Broken track between pin 4 of 2128 SRAM @ 10R and pin 4 of 2128 SRAM @ 10S. Repairing the track resulted in the fault below.
    In attract mode at the high score table, there is a white jumbled Pacland logo superimposed over the text. During game play it looks like there is a black block following Pacman. Broken track between pin 3 of 2128SRAM @ 10R and pin 3 of 2128 SRAM @ 10S. Repairing the track fixed the problem.
    Game freezes with a green crosshatch in the top half of the screen. 68A09 processor faulty. Replacing the processor fixed the problem.
    Bottom half of Pacland logo distorted. Bad SRAM @ 10R. Replacing the SRAM cured the problem.
    During game play, Pacman is not at "ground" level but in the top half of the half of the screen. When he jumps his hat appears at the bottom of the screen. Fire hydrants appear as a green pacman. Pin 9 of 74LS245 @ 8P stuck high. Replacing the IC cured the problem.
    Colours incorrect. Specifically, the green portion of the Pacland logo. R32 (220ohm near video connector) open circuit. Replacing the resistor fixed the problem.

    Phoenix (Amstar/Centuri/C.G.I/Taito)

    ProblemSolution
    Game resets during attract mode. Bad EPROM's. Re-blow a new set of EPROM's.
    Low sound. Replace volume pot.
    Tinny sound. Dry joints on capacitors in audio circuitry.
    No sync. No output from pin 2 of 74LS05 @ 29. Replacing IC fixed problem.
    Garbage on screen. Clock to 8085 processor was present but there was no activity on any of the busses. Replace processor cured the problem.
    Colours incorrect. Nest wrong colour and the eagle wings are two tone. Pin 7 of 74LS174 @ IC32 stuck high. Replacing the IC cured the problem.
    Alien swoop sound incorrect. No output from 555 timer @ IC51. Replacing IC solved the problem.
    No alien swoop noise. No output from 555 timers @ IC 50 & IC 51. Replacing the timers fixed the problem.
    No ship fire or explosion. All outputs of 4006 @ IC45 stuck high. Replacing IC fixed the problem.
    Ship explosion too short in duration. C25 weak. Replacing the capacitor fixed the problem.
    Intro music clipped / distorted. Melody generator chip, MN6221 @ IC49 faulty. Replacing this IC fixed the problem.
    No fire or ship explosion sound. Output of 555 timer @ IC42 stuck high. Replacing IC fixed the problem.
    Game displays garbage at power on. By manually resetting the processor the game started fine. Electrolytic capacitor C2 was broken thus not resetting the game at power on. The capacitor forms a power on reset function. Replacing the capacitor cured the problem.
    Black screen. Sync was present but there were no colour outputs at the edge connector. All outputs of 7407 @ IC47 stuck low. Replacing the IC cured the problem.
    Game resets at attract mode. Text fine until birds appear on score table and then the game resets. Bad EPROMS @ IC39 & IC40. Blowing new EPROMs fixed the problem.
    Game displays OK but it won't coin up. R17 missing. Replacing the resistor fixed the problem.
    Ship moves to right without any joystick action. Bad 74LS157 @ IC12. Replacing IC fixed the problem.
    Excess noise. Lots of background noise. 100nF capacitor (on back of board) between pins 2 & 3 of LM380 @ IC43 missing. Replacing the cap fixed the problem.
    Game (at switch on) coins itself up and starts to play. The ship fires but doesn't recognise any controls. Faulty 8085 processor. Replacing the processor fixed the problem.
    Game starts itself as soon as credits are inserted. Faulty 74LS244 @ IC4. Replacing IC fixed the problem.
    No ship fire or explosion noises. Faulty LM 324 @ IC46. Replacing IC fixed the problem.
    Incorrect alien swoop noise. Bad capacitor @ C22. Replacing capacitor fixed the problem.
    No sound. C35 broken. Replacing the capacitor fixed the problem.

    Pleiades (Midway)

    ProblemSolution
    Garbage on screen. 8085 processor @ location IC8 faulty. Replacing the processor fixed the problem.
    Picture not perfectly stable. Weak output from 74LS05 @ location IC35. Replacing the IC cured the problem.

    Pole Position II (Atari)

    ProblemSolution
    RAM 8 error at power on. Base collector junction of Q4 was open circuit. Replacing the transistor cured the problem.
    At the end of the self test mode, instead of starting the attract mode, the cross hatch remains superimposed upon two tracks arranged in a "V" shape. The game will then reset and go through the self test again. Bad connection on the interconnect board.

    Puckman (Pacman bootleg)

    ProblemSolution
    Game will not initialise. All outputs of 74LS74 @ 6C (top board)floating. Replacing the IC fixed the problem.

    Rally X (Namco)

    ProblemSolution
    Seven white blocks across the middle of the screen. 74LS74 @ 7N (top board)and 74LS86 @ 7P (top board) had faulty outputs. Replacing the IC's did not cure the problem. 74LS04 @ 9N (topboard) had all output's floating. Replacing this IC made the game go into it's self test mode.
    No text. Sprites were blocky. 74LS00 @ 8N (top board) had outputs at pins 8 & 11 floating. Replacing the IC fixed the board.
    No sound. Pin 7 of audio amp was broken. Resoldered leg to cure the problem.
    Incorrect colours. White is shown more as a cream. Bad PROM @ 11D (top board). Replacing the IC cured the problem.

    Scramble (Konami)

    ProblemSolution
    Completely dead. Resistor missing from oscillator circuit. Replacing resistor caused crystal to oscillate and the game worked fine.
    Stars flashing constantly / irratically. Bad outputs on 74LS08 @ 6P. Replacing IC cured the problem.
    Colours incorrect. Targets breaking up. Landscape breaks up. Bad outputs on 74LS367 @ 4N. Replacing IC cured the problem.
    No sound. 2114 SRAMs at 6C & 6D (on sound board) faulty. Replacing the ICs fixed the sound.
    All motion objects except ship (rockets, etc) are upside down. Track broken between 4J pin 19 and 6N pin 13. Repairing the track fixed the problem.

    Space Invaders (Midway)

    ProblemSolution
    No missile fire sound. LM3900 @ M4 faulty. Replacing the IC cured the problem.
    No saucer hit noise. LM3900 @ M5 faulty. Replacing the IC cured the problem.

    Space Invaders (Taito) - 3 board set

    ProblemSolution
    Solid line through each invader. This prevents you from shooting the invaders. Pin 12 of 74174 @ location 15 on top board stuck high. Replacing IC fixes the problem.
    TILT displayed at power on. All outputs of 7414 @ location 2 on the top board stuck high. Replacing the IC fixes the problem.
    Colours incorrect. All outputs of 7416 @ location 21 on top board floating. Replacing IC fixes the problem.
    Game repeats title screen. No output from pin 6 of 74LS86 @ location 39 on processor board. Replacing the IC fixes the problem.
    No missile fire sound. No output from pin 4 of LM3900 @ location 25 on the top board. Replacing the IC fixed the problem.

    Space War Part 3 (Taito) - 3 board set Space Invaders conversion

    ProblemSolution
    Colour bands on screen with blank band down the middle. All outputs of 7442 @ location 3 on the bottom board stuck high. Replacing the IC solved the problem.

    Star Fighter - Scramble conversion

    ProblemSolution
    Blocks of garbage at power on. PIA (8255) @ 1/2D on top board faulty. Replacing IC cured the problem.

    Star Wars (Atari)

    ProblemSolution
    No TIE fighters. All other objects visible. When you reach the Death Star the game hangs. Bad mathbox PROM @ 7K on the main PCB. Re-blowing a new PROM fixes the problem.
    First phase of the TIE fighters is OK. When you reach the Death Star the game pulses on and off causing the spot killer to kick in. Bad address controller gat array @ 2J on the AVG board. Replacing the IC cures the problem.

    Super Pacman (Namco)

    ProblemSolution
    Self test halts at I/O test with a 1 displayed. Bad 56xx custom IC @ 4F on the top board.
    Self test halts at I/O test with a 2 displayed. Bad 56xx custom IC @ 4C on the top board.

    Terra Cresta (Nichibutsu)

    ProblemSolution
    Background sounds faint/scratchy. Bad capacitor (next to LM324) on daughterboard. Replacing the cap fixed the problem.
    Landscape graphics corrupt. Game plays otherwise. All outputs of 2016 RAM @ 20D (on top board) floating. Replacing the IC cured the problem.

    Tiger Heli (Romstar)

    ProblemSolution
    No motion objects on screen. Bad outputs on 74LS02 @ 7M on board GX-511-A. Replacing the IC fixed the problem.

    Tower Of Druaga (Namco)

    ProblemSolution
    Game will not sync. Bad output on pins 8 and 9 of 74LS109@3B on top board. Replacing the IC fixed the problem.
    No melody music. Can hear fire sounds but no tune. No output from AY-3-8910 @ 11/12G. The sound generator is disabled due to all the outputs of 74LS02 @ 9F (top board) being stuck high. Replacing the IC fixed the problem.

    Wonderboy (Sega)

    ProblemSolution
    Lines across motion objects. Not jailbar effect but large lines. Daughter card not seated properly. Re-seating the daughter card fixed the problem.
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