Brian E. Brzezicki
Copyright 2012 - present
Version 1.0l 02/03/2012

Disclaimer
Use this at your OWN risk, do NOT sue me if it breaks your board... if your doing this your board is probably already broken though ;)

Millipede Troubleshooting Information

Game Board #1 11/9/2012

Problem:

    Game resets constantly, a screen of green "D"s can be seen briefly... screen is rolling.

Troubleshooting/dianosis steps:

  1. Noted that the 2 chips in the slots that should be POKEYS did not look correct. One was label "Taito" and one was labeled "Konami", pulled them out
  2. After pulling out mysterious chips that were in the POKEYs place, the game booted correctly.
  3. Replaced chips with real POKEYS and game worked fine
Game Board #2 11/18/2012

Problem:

    Game resets with 4 beeps

Troubleshooting/dianosis steps:

  1. Checked with Fluke 9010a memory tests, all memory starting at 0x1000 reads that bit 0x10 is always on
  2. Tried writing to memory at various memory location in playfield memory noted that bit 0x10 is always set, HOWEVER the video display shows the proper characters! In this case the memory itself HAS to be good, as the screen circuitry reads from it and it's displaying the correct tile.
  3. Replaced 74LS373 at location 4P (data buffer going back to CPU). That fixed the problem
Game Board #3 1/24/2013

Problem:

  • Game beeps 9 times (indicates 2101 at J2), screen is full of a few lines of mushrooms then a bunch of "G"s

Troubleshooting/dianosis steps:

  1. tested continuity between pins on Address Bus between J2 and K2, found that A4 was NOT connected on J2, and A2 and A4 on J2 were shorted together.
  2. A few of the 2101 RAM chips had been socketed, including the on at J2
  3. Looked at board, was clear that the trace to A4 was bent and touching the pin for A2
  4. Pulled up socket, alot of traces and pads were damaged, Noted damaged wires
  5. Put in new socket, had to jumper a wire between J2 and K2 for A4, A1, DI2, and DI4
  6. Game powered on, put in self test mode, which indicated POKEY 1 failure.
  7. Swapped POKEY 0 and POKEY 1 to see if error swapped... it did, so replaced the bad POKEY with a known good POKEY, retested
  8. Game works!
Game Board #4 2/15/2013

Problem:

  • Game has purely red screen, game flashes like it's resetting at the work RAM checks, (before the video ram tests). No sound/beeps though

Troubleshooting/dianosis steps:

  1. The video ROM chips are really loose. Pressing on them give garbage on the screen
  2. Took out the Fluke 9010a, got a memory error bit 08 (low half of address) on some addresses. That's a 2114 at F2.
  3. Replaced 2114 at F2, and installed a socket. Memory passes, game looks like millipede attrack screen but all blocky (no actual sprites, only colored block), pusing on the video ROM chips makes it look normal pixes but discolored
  4. Resocketed the 2 video ROMS
  5. Game looks normal now, but pokeys are failing in test mode, no sound.
  6. swapped out POKEYS with other POKEYS, everything OK.
  7. Swapped back in 1 bad POKEY, test shows 1 pokey error
  8. Put back good pokeys!
  9. Game works!
Game Board #5 2/15/2013

Problem:

  • Game sometimes boots up, but graphics issues
  • When put into test mode it indicates ram errors (even though it already passwd RAM tests
  • Sometimes 4 beeps, sometimes 2 beeps

Troubleshooting/dianosis steps:

  1. Did RAM test with Fluke 9010A, sometimes passwed most of the time failed, video RAM always failed.
  2. RAM tests indicated inability to drive data bus
  3. Noted as I did ram checks the output noise would increase in volume
  4. Probed pin 12 on LS244 (1C/D) which drives the "Dir" on the LS254 at 4E, noticed the output was not the same as the input, socketed and replaced... still had same issue
  5. Removed chip and noticed that the output was beign driven somehow... followed the traces to the POKEYS.
  6. Remove the POKEYS and noted the board no longer had memory errors
  7. Replaced POKEYs with different ones and the game worked fine!
Game Board #6 2/16/2013

Problem:

    Garbage on screen

Troubleshooting/dianosis steps:

  1. Did RAM test with Fluke 9010A, work RAM and video ram passed
  2. Pull out ROMS replaced with known good ROMs
  3. Game works
Game Board #7 2/17/2013

Problem:

  • Garbage on screen
  • no sound

Troubleshooting/dianosis steps:

  1. Did RAM test with Fluke 9010A, work RAM passed, video ram failed with DCD errors on bit 1.
  2. probed various points on address bus wire #1, noted many points did not have any signal.
  3. found address bus 1 wire was disconnected under one of the 2114s that had been replaced with a socket and had the trace broken.
  4. removed socket, fixed break with a jumpter wire.
  5. Game works
Game Board #8 2/19/2013

Problem:

  • screen red
  • no sound

Troubleshooting/dianosis steps:

  1. removed pokeys
  2. Tried to test memory with Fluke 9010a, fluke kept resetting with POD timeout
  3. Replaced crystal, same problem
  4. used logic probe and noted clock was dead
  5. traced back clock circuitry with logic probe, testing the different inputs and outputs
  6. Pulled the CPU out and noticed that the clock worked when CPU was out
  7. pulled out chip D6, noted that pin output 12 was pulsing, that should not have pulsed since D6 provides the output on pin 12.
  8. Found video RAM was removed and resoldered.
  9. found that on video RAM, Address line #1 was tied to the clock input
  10. found and removed a solder short between the the address #1 trace and the clock pin on one of the video RAMS
  11. game works, however video ROM sockets are really lose and need to be replaced, sometimes lines through screen, they go away if you push on the video roms.
  12. put pokeys back in, found the system would not boot with one of the pokeys in, and both were ultimately bad
  13. replaced POKEYS
Game Board #9 2/28/2013

Problem:

  • 3 beeps (indicates error in video Memory M2)

Troubleshooting/dianosis steps:

  1. Looked at M2, saw it had previously been replaced... concerned that it might not really be a memory issue with M2
  2. removed M2, put in a socket, and put in a new 2101, still 3 beeps
  3. Looked at board, saw an area where it looks like the board was impacted by somethign, traces looked smashed together. Did some continuity checks and found a 2 trace lines touching. used a the multimeter pin to remove the metal connecting the two pins
  4. Game works!
Game Board #10 5/04/2013

Problem:

  • #2 beeps and half a screen of 0's

Troubleshooting/dianosis steps:

  1. The half screen of zeros indicates the video hardware is getting the code to write the tilemap of 0 in those locations. Memory or buffer must be bad.
  2. The beeps indicate a memory error.. maybe there is something affecting both RAM sections
  3. Get out the Fluke run a memory test on 0x0000-0x3FFF. Got DCD errors.
  4. Run long RAM test on video memory section 0x1000-0x13EF. Got low 4 bit error on 0x1000-0x100F, 0x1040-0x104F, 0x1080-0x108F This correlates to one specific 2101 specifically M2. Got out logic probe and noticed the outputs were floating.
  5. removed M2, put in a socket, and put in a new 2101, screen of 0s went away, and now passed memory test with fluke. Game gives 2 beeps though as expected.
  6. Remove E2, socket and replaced with 2114, still getting 2 beeps
  7. Remove F2, socket and replaced with 2114, game works!
Game Board #11 6/19/2013

Problem:

  • Game missing ALL video RAMS (2101s)
  • Incorrect random chips are in the POKEY section
  • Back of board has trace breaks and scratches

Troubleshooting/dianosis steps:

  1. Pulled of Random chips in the POKEYS location.
  2. Did a RAM long with fluke 9010A on 0x0000-0x03FF, got two memory locations with BTS 01 errors.
  3. the lower 4 bits come from 2114 at F2, removed, socketed and replaced chip, RAMs now pass long memory test
  4. Fixed some trace breaks on the back of the board
  5. installed sockets on two of the missing 2101 video RAMS. inserted new RAM.
  6. Put game into self test, video looks correct for that section of RAM.
  7. Installed sockets and new RAM in all other video sections
  8. Installed new POKEYS
  9. Self test mode is still giving 4 beeps, but the video display during test looks fine
  10. hooked up to fluke did a RAM long on all Video RAM addresses 0x1000-0x13FF returned BTS 20 error on all addresses
  11. manually set location 0x1000 to 0x00 it displayed the correct tile on the video display, but the fluke is coming back with a value of 0x20.



    • Stepped trhough a couple more values to make sure the screen is displaying the correct value. it is. This means the RAM is being written too good and the video display can see it, but the data gettting back to the CPU is bad.. will need to check the buffer and bus lines for the 6th data bit.
    • Replaced 74LS373 @ 4P, issue remains
    • Looked for continuity problems on the DATA bus for bit 6 (or bit 5 if counting from 0) between pin 6 on the 74LS373 @ 4P, and pin 16 on the 74LS245 @ 4E, found a break.
    • repaired broken trace between pin 6 on the 74LS373 @ 4P, and pin 16 on the 74LS245 @ 4E.
    • Board works!
Game Board #12 8/13/2013

Problem:

  • Game has random boxes on screen, flashing, not steady, no boot, no sound

Troubleshooting/dianosis steps:

  1. Noticed a smell coming from the board when powered on, noticed 2114 RAM chips are super hot to the touch (burning)
  2. did a fluke BUS test, coming back with data bits stuck.
  3. Pulled POKEYS
  4. Pulled ROMS
  5. replaced 2114s
  6. now getting RAM DCD errors, replaced 74LS244 @ 1D/E, after which fluke passes LONG RAM test for 2114 range (0x0000 - 0x03FF)
  7. Put ROMS back in
  8. Put POKEYS back in
  9. Board now boots to super fast beeping, white screen
  10. Getting all kind of memory errors on the 2101 section of RAM (0x1000 - 0x13FF)
  11. Pulled POKEYS, no change to 2101 RAM range test
  12. a month and a half passes and I get to working on it again... a bunch of stuff (9/24/2013)
    • Replace 74LS153 @ 4J, don't think that made a difference
    • Bad 2101s at 2J, 2L, 2M, 4K, 4N
    • Bad 74LS157 @ 10C
    • Bad 82S25 RAMs @ 11C, 10B (don't have replacements)
    • Now everything works except screen colors are messed up as I don't have 82S25s to put to replace the video RAMs... but everything else works
    • 10/15/2013 - recieved new 82S25s (74S89/74S289) installed and everything works fine!
Game Board #13 8/29/2013

Problem:

  • Game has messed up graphics, including lines through the graphics.

Troubleshooting/dianosis steps:

  1. Pushed on video ROMs, things got better, but not totally.
  2. felt the ROM sockets, very loose.
  3. Unsoldered old sockets, the pins were nearly falling apart.
  4. Soldered in 2 new 24 pin sockets
  5. brushed of tarnish on EPROMS
  6. Game works!
Game Board #14 9/18/2013

Problem:

  • Millipede with Braze Multipede kit installed.
  • Owner stated that thegame stopped working mid game. no sound no picture.
  • Put on test bench, confirmed no sound, no picture.
  • Sometimes their would be a picture but it will be all stripes, other times there was no picture.

Troubleshooting/dianosis steps:

  1. Noted reset line is permanently low.
  2. Disabled watchdog circuit reset line went back high. Manually reset, but nothing changed.
  3. Board passed Fluke 9010A long RAM test on work RAM (0x0000-0x03FF)
  4. Board passed Fluke 9010A long RAM test on video RAM (0x1000-0x13EF)
  5. Removed multipede kit, installed original ROMS
  6. Board has a stripped colored screen, running RAM long on video section doesn't show what it should as far as graphics go. Notice hissing sound during RAM long on video section.
  7. Removed ROM, verified on PC with ROM programmer, version 3 code.
  8. Inserted ROMs back into the board, validated ROM signatures with Fluke, all game ROM code OK!
  9. Looked at reset/watchdog circuits, validated 8F and 10E inputs/outputs are good, looked at 9F which is not changing... but input from !VBLANK is being held high. need to check out vblank
  10. need to look at the frequency divider circuit.
  11. Looks like pin 11 on 8E is not working correctly, it is stable where it's complement on pin 10 is NOT, it also should not be stable.
  12. Replaced 74LS175 @ 8E, board fixed!
Game Board #15 10/12/2013

Problem:

  • Owner claimed POKEY diagnostic code was bad
  • mushrooms were all on left side in a row
  • game reset after clearing level 1

Troubleshooting/dianosis steps:

  • tested work RAM (0x0000 - 0x03FF) OK
  • tested video RAM (0x1000 - 0x13EF) OK
  • tested ROMs from CPU standpoint with Fluke 9010A, OK, ROMS are version 3
  • put machine in test mode, POKEY errors
  • Swapped out POKEYS with known good, OK
  • Swapped out individual POKEYS, both were bad
  • Installed new POKEYS, everything works OK!
  • Game works!
Game Board #16 12/24/2013

Problem:

  • Game extremely dark, would fade in and out
  • Some graphics just blocks
  • Sound messed up
  • Mushrooms on lined up on left side of screen

Troubleshooting/dianosis steps:

  • Self test showed bad POKEY, replaced, fixed mushroom problem
  • Found Graphics ROM in backwards, fixed
  • Found Graphics ROM sockets horribly corroded, replaced
  • Found +15V dead, replaced both 7815 and 7915 voltage regulator
  • replaced LM324
  • game works!
Game Board #17

Problem:

  • Game does 4 beeps

Troubleshooting/dianosis steps:

  • Did RAM long check on 0x1000 - 0x13FF, found DCD error @ 0x1000 bit 7.
  • wrote and red to address 0x1000 and 0x1080 found the top 4 bits were conflicting
  • Replaced 2101 @ N4
  • game works!
Game Board #18

Problem:

  • Board is dead

Troubleshooting/dianosis steps:

  • Powered on board. found the 7815 voltage regulator was actually a 7905 and burning hot.
  • removed 7905 and replaced with a 7815
  • did a fluke long RAM test on 0x0000 - 0x03FF - got errors
  • did a fluke long RAM test on 0x1000 - 0x1EFF - got errors
  • pulled POKEYS and ROMS
  • replaced ROMs with known good ROMS
  • did a ROM check with the Fluke 9010A, all code ROMS ok
  • did a RAM LONG on 0x0000 - 0x03FF - OK
  • did a RAM LONG test on 0x1000 - 0x13FF - OK
  • replaced the POKEYS and did a ROM LONG on 0x0000 - 0x03FF - OK
  • put the pokeys back and turned the game on, game was playing but with messed up graphics
  • removed the video ROMs and replaced with known good video ROMS, fixed things for the most part, but sprites were all white
  • While probing the TTL circuits in the motion object color section, noticed that the 82S25 @ B10 was super hot. Replaced the 82S25.
  • Game works!
Game Board #19 5/2/2014

Problem:

  • Board constantly resets

Troubleshooting/dianosis steps:

  • Game passes all RAM tests
  • Game passwd fluke ROM tests
  • found some questionable sockets/repairs, fixed
  • Now game resets... but only sporatically cannot reproduce, will happen usually within an hour or so though on test bench
  • Hooked game up to cabinet, noted trackball controls don't work, moves on it's own
  • replaced 74LS257 @ 9N
  • Controls now work
  • Game Works!
Game Board #20 8/18/2014

Problem:

  • Garbage on screen

Troubleshooting/dianosis steps:

  • Put in Fluke did RAM long test on workpad RAM 0x0000 0x03FF - OK
  • Did RAM long test on Video RAM range 0x1000 - 0x13FF - OK
  • Replaced CPU, game booted up
  • Game was making screetching sounds.
  • Test mode indicated Pokey 1 and Pokey 2 were bad
  • Tested Both Pokeys found 1 bad and replaced.
  • Screetching sounds still remain and both pokeys shwoing bad in tests mode
  • Used Fluke to query various addres ranges while testing POKEY chip selects (pin #10 and #11 on 74LS139 @ E3 found pin 10 was always stuck LOW
  • Replaced 74LS139 @ E3, but the problem remained.
  • Found pin 10 was shorted to ground, two traces right near E3 were smashed togther. Seperated traces
  • Game works!
Game Board #21 9/9/2014

Problem:

  • Game is not working
  • getting 6 beeps, but no looping
  • Losing sync on LCD monitor
  • Owner said 6C kept burning out, and board was physically burnt underneath

Troubleshooting/dianosis steps:

  • Put in Fluke did RAM long test on workpad RAM 0x0000 0x03FF - OK
  • Did RAM long test on Video RAM range 0x1000 - 0x13FF - All kinds of erractic errors. Reading from a single RAM location in the 0x1000 - 0x13FF range shows the values jupming. the dsgree and random type of errors indicated that it's not likey really a memory error.
  • Started verifying the sync chain circuits, first 12Mhz, OK
  • checked 6Mhz... all messed up, frequency is jumping a bit as well as signal base and max on curve as viewed on an oscope
  • 6Mhz is generated at pin 14 on 74LS163 @ 6D, pulled socketed and replaced.
  • Still getting wierd 6Mhz on pin #14 of 6D
  • oh.. no one of the chips that uses this output as input must be bad and adding signal to the wire.
  • first chip is the reported 6C (74S04), socketed and replaced still getting bad signal.
  • removed chip from socket, problem goes away.
  • removed 3904 transistor that feeds 74S04, replaced, no change
  • put back 74S04 and removed 74LS163 from socket on 6D. noticed that there is a signal on the output pin still.
  • was a bit confused now as that seemed to indicate that 6C was bad, but further thinkign about it realized that 6C feeds other chips that are potentially bad, so pulling 6C could make other bad chips "unplugged" therefore making it seems that 6C is bad when really it's just pulling that chip effectively turns off another bad chip.
  • Pulled other two obvious chips immediately after the 74LS163 on schematic. This was 74LS74 @ 9h and 74LS109 @ 8h, still reading bad signal on pin 14 of 6D.
  • a bunch of other chips use the 6Mhz signal as a clock signal, one by one found a chip that uses it as an input, and carefully cut the pin rather than removing the whole chip, thus isolating the 6Mhz signal from a potentially bad chip. Found on 74LS183 @ 8D when pin cut the signal at pin #14 of 6D was now good
  • Soldered on a socket at 8D, and inserted a new 74LS163.
  • Re-tested signal on pin #14 @ 6D, OK!
  • soldered a glob to bridge the cut pins on the chips that I cut pins on
  • sodlered in new 74LS109 @ 9h, and new 74LS74 @ 8h
  • Game works!
Game Board #22 9/18/2014

Problem:

  • Game is not working
  • Screen has garbage

Troubleshooting/dianosis steps:

  • Measured system clock pin #37 on CPU - OK
  • Measure reset line. stuck LOW - this is a problem
  • Working back from the reset line, verified 8F is OK
  • 9F pin #11 stuck high, pin #14 is not pulsing, traced back to bad 74LS163 @ DF, replced
  • Now pin #14 on 9F is pulsing at 60Hz, however output pin #11 is still stuck high, and pin #12 is never pulsing
  • Noted that pins #6 and #7 (same signal) on 9F was high (should be low)
  • tracked back to 8F output is high, input is low, bridging the reset line doesn't have any effect.
  • Replaced TL082 @ 11H
  • Now pin #1 @ 8F is now high and output pin #2 is LOW
  • Now 9F is pusling correctly, and reset line on CPU is no longer stuck low!
  • Game works!
Game Board #23 9/30/2014

Problem:

  • Game is not working
  • Screen has garbage

Troubleshooting/dianosis steps:

  • Measured system clock pin #37 on CPU - OK
  • Inserted Fluke 9010A 6502 POD, failed BUS test, with error CTRL 00010000, this is a failure to be able to drive the R/W line.
  • The only chip in the circuit that would stop the CPU from being able to drive R/W is a 74LS244 @ 1C/D, removed, installed socket and replaced
  • Game passes bus test now
  • Game passes RAM long on range 0x0000 - 0x03FF (2114 RAMs)
  • Ran RAM long on video RAM (2101s) address range 0x1000 - 0x13FF, gets BTS error 0F on addresses 0x1000-0x100F, 0x1040 -0 0x104F. This is clearly an issue with the 2101 RAM at M2.
  • Before removing preformed a write on address 0x1000 in loop mode to ensure the write signal is actually getting to the RAM chip (pin #20), it was.
  • Removed the 2101 @ M2, installed socket and replaced
  • Game works!
Game Board #24 2/5/2015

Problem:

  • Game plays blind. On LCD, not getting a good SYNC

Troubleshooting/dianosis steps:

  • tested !Composite Sync and VSYNC lines, all messed up
  • verified sync chain, all 74LS163s in H and V sync are good
  • probed on output pins of 74LS175, pin 7 was all messed up and defintely NOT the inverse of pin 6
  • Noted previous work on socket/chip at 8E, removed to verfify no bridged traces - OK
  • pulled chip from 8E, mesaured pin 7, there was a signal on it, (there should NOT have been since it was an output, and the chip was pulled! must have a trace bridged somewhere (there was previous repair work by someone on this board)
  • Removed 7407 @ 12C, it is common with the signal line from 8E pin 7 there was repair work on this previously, figured maybe a solder blob under the socket - but still signal on pin 7 of 8E.
  • Removed 74LS86 @ 6N, it is common with the signal line from 8E pin 7 there was repair work on this previously, figured maybe a solder blob under the socket - but still signal on pin 7 of 8E.
  • Probe the pins of 6N found a stray signal matching the "signal" still on pin 7 of 8E, traced the trace back to find some smashed toghether traces a few inches above the chip.
  • seperated the smashed traces
  • Remeasured pin 7 on 8E, now stray signal is gone!
  • Resocketed removed sockets and replaced chips.
  • Game works, but shooter does not move left or right
  • Had someone move trackball in North East direction, measured output of schmitt trigger @ 11P pin #11 (horizontal clock) - OK
  • Had someone move trackball in North East direction, measured output of schmitt trigger @ 11P pin #8 (veritical clock) - No signal
  • Replaced 45848 @ 11P with compatible MC14584
  • Game works!
Game Board #25 3/9/2015

Problem:

  • Game is dead, random junk on screen which changes between resets and even without reset

Troubleshooting/dianosis steps:

  • Tested clock OK
  • Tested reset line, resetting
  • Hooked up Fluke, ran bus test, got back address line #9 stuck
  • did continutity test from address line #9 (pin 18 on 6502) to ground, found no resistance
  • Cut pin #15 on 74LS244 @ 1C/D (address line #9 input), the only place that address 9 goes to to isolate issue
  • did continutity test from address line #9 (pin 18 on 6502) to ground, found no resistance still.
  • Resoldered back pin #15 @ 1C/D
  • Desoldered CPU socket
  • found a little solder blob/metal shaving bridging pin 18 to ground
  • Removed metal bridge, resoldered socket
  • did continutity test from address line #9 (pin 18 on 6502) to ground, now it OK!
  • did fluke long RAM test on all RAM ranges - OK
  • Powered up board without fluke, game boots
  • started game, found issue with mushrooms all on left side of screen and game resets
  • Put game in self test mode, found bad POKEY
  • Replaced bad POKEY, with known good POKEY
  • Game still is having issues alot with all mushrooms on left side of screen and game resetting, seems to change with moving board.
  • Removed other POKEY, found sockets to be questionable, replaced both POKEY sockets.
  • Game still has issue.
  • Kept game in self test mode a bit longer, noticed that the POKEY registers good and bad, good and bad and some dip switch settings (which are controlled by the POKEY) change.
  • Pulled POKEY and replaced with known good POKEY.
  • Game works!
Game Board 26 8/14/2015

Problem:

  • Game is dead, LCD syncing, but no image, no sound either.

Troubleshooting/dianosis steps:

  • Check 1.5Mhz clock - OK
  • found cracked 7815 @ VR1 - replaced
  • now game boots but sprites and backgrounds are not correct
  • looks like bad sockets or roms, tested roms in another machine ok
  • replaced sockets which were very bad, no changes but looks like a ROM/socket issue
  • found a bad 74LS157 @ 6P desoldered and pin 12 was broken off from the chip, replaced and that fixed the sprite issue
  • something is messing up memory. game doesn't work when pokeys in
  • in test mode get flashing and changing dip/and trackball settings.
  • Pulled POKEYS, tested scratch pad RAM, video RAM and ROMS - OK
  • Replaced both POKEYS with new ones, everything looks good
  • Swapped in each original POKEY one at a time, both tested BAD in self test
  • Marked old POKEYs as bad and put back in new POKEYS
  • Game works!
Game Board 27 10/23/2015

Problem:

  • Game is dead, static garbage characters on screen

Troubleshooting/dianosis steps:

  • after initially testing the reset line to find it low (it wasn't, I had changed the timing on my oscilliscope and forgot to set it back.) found the system watchdogging
  • with watchdog disabled system was not watchdogging
  • CPU clock OK
  • attached Fluke 9010A, bus check showed address bits 6 and 7 were tied together
  • checked continuity with multimeter and they were
  • Examined the board, found smashed together and cut traces near the CPU socket
  • Removed socket, removed smashed traces, fixed cut trace
  • Game boots up now and gets through test mode ok!
  • Ran Fluke 9010A RAM long test on scratchpad RAM (0x0000 0x03FF) and video RAM (0x1000 - 0x13FF) both OK
  • Game works
Game Board 28 11/18/2015

Problem:

  • Visible inspection shows board is missing video ROMs
  • One POKEY is rusty both POKEY sockets look bad

Troubleshooting/dianosis steps:

  • Removed POKEYS
  • Game works with blocks as sprites and no tiles (expected behavior with missing video ROMS
  • Installed new video ROMs
  • Game boots fine
  • Removed old POKEY sockets just because they were such a mess, cleaned surface rust of POKEY pins
  • Installed in sockets and reinstalled POKEYS
  • Game doesn't boot
  • Pushed down on CPU
  • Game started working
  • Removed CPU socket (it was also bad), and replaced
  • Game works!
Game Board 29 1/30/2016

Problem:

  • Game does not boot, static screen of garbage

Troubleshooting/dianosis steps:

  • watchdog is going
  • CPU clock is wrong (700khz)
  • 7F, input SCRAM OK? others look fine
  • 1b pin #2 (SCRAM) and #9 are showing bad
  • found a smashed trace near B1, cleared, now getting 4 beeps
  • pin #2 on B1 still going at 700khz, pulled B1 and still getting a signal, must have a bridged trace. found it
  • clock is now good at 1.5Mhz
  • now getting 10 beeps
  • RAM long 0x0000 - 0x03FF - OK
  • noticed that 2 RAMS have been replaced.
  • RAM 0x1000 - 0x13FF getting BTS F3 errors. these vibe with the pulled chips
  • pulled the RAMs they were heavily soldered put in sockets and new RAMS, now tests ok
  • games boots
  • getting unstable graphics though
  • replaced blue transistor @ q4, no change
  • found cut traces near 9B , that fixed some problems, but sprites are still messed up and colors are off.
  • hmm... lost my notes regarding what the reset of the solution was
  • game works!
Game Board 30 2/27/2016

Problem:

  • Game does not boot, messed up screen
  • D's everywhere on the screen, some tiles flashing

Troubleshooting/dianosis steps:

  • sockets look back (CPU and POKEYS)
  • clock ok (pin #37 on CPU good at 1.5Mhz)
  • no voltage between pin 1 and pin 8 on 6502?
  • pulling off CPU and POKEY sockets, many pins fell off
  • replaced all 3 40 pin sockets
  • RAM tests
      LONG 0x0000 - 0x3FF
    1. BTS 0x10 on addresses 0x010f amd 0x020f - that's 2114 @ 2E pulled, socketed and put on new chip - OK
      LONG 0x1000 - 0x13FF
    1. BTS 0xD0 @ 0x1000 - 0x100F (N2)
    2. BTS 0xF0 @ 0x1010
    3. BTS 0x10 @ 0x1011 -
    4. BTS 0x0F @ 0x1030 - 0x103F
  • something is effecting the high bits of video RAM (you can see the screen shifting as well as the fluke)
  • lets start with the easy looking issues
  • 1030 BTS 0x0F that's 2J - pulled resocketed and replaced - OK
  • 1000 BTS 0xD0 that's N4 - pulled resocketed and replaced - OK
  • 1010 BTS 0xF0 and 0x10 that's M4 - pulled resocketed and replaced - OK
  • 1020 BTS 0x80 thats 4J - pulled resocketed and replaced - OK
  • ROM sockets are messed up, removed them, found a bad ROM, replaced
  • Game Works!
Game Board 31 3/13/2016

Problem:

  • Game does not boot, all static tiles

Troubleshooting/dianosis steps:

  • noticed ROM OE test pointswere broken thing changed as I pushed on the ROM test points
  • removed test points found broken wires going to from the ROM test points to the OE lined, fixed the traces.
  • Now the game boots but sprites are messed up, looks like the sprite is made up of 2 copies of the left 1/2 of the sprite.
  • looked to the motion picture (sprite) circuit, the adders and counters or often bad, 74LS83 @ 6j tested bad, swapped out but there was no change.
  • noticed video sockets looked hacked up, cleaned up messed up video sockets, replaced and repaired
  • replaced 74LS83 @ 6h - nochange
  • found cut trace running under 6k, fixed no change
  • 6J pins 2 and 5 have continuity between them, they not supposed to be
  • noticed 6k is also soldered wierd, removing 6k solved the problem
  • 6k is an 74LS20 which I don't have any of :(
  • replaced with a pull from a parts board, now sprites looks OK
  • color seem overlyy yellow and blue is too dark or missing
  • replaced Q4 transitor (3906) one leg fell off while dosoldering, that fixed the problem with yellow and wierd blue except now blue is crazy too much, for example the bottom of the screen which is usually a light grey/green is light blue!
  • replaced 3904 @ Q2 and Q3, no change
  • replaced the 3 3906 transistors behind Q3, Q4 and Q5
  • Game works!
Game Board 32 6/19/2016

Problem:

  • Game does not boot, all static tiles

Troubleshooting/dianosis steps:

    Game does not work, customer said board is shorting power out
  • Found watchdog is dead
  • LCD is not syncing
  • vblank is shared between watchdog and POKEY and sync
  • 74LS163 @ 6D (first chip in circuit) pins 14, 13, 12 output OK however pin #11 is dead
  • Replaced 74LS163 @ 6D, now have watchdog, sync and clock, but only purple and red lines on the screen
  • RAN a fluke Ram long test 0x0000 - 0x03FF, BTS errors 0x80 - that's 2114 RAM @ 2E, replaced
  • Now getting RAM DCD errors, manually writing and reading addresses seems to indicate the new RAM is ok, but the low bits on 2F might be bad
  • Replaced 2114 @ 2F, now have video problems
  • Video ROMs totally destroyed, many missing pins
  • Replaced sockets and put in new ROM, still a few issues, found Address line #A5 trace was missing, fixed trace?!?
  • Did a RAM long for the video RAM range (0x1000 - 0x13FF) BTS errors 0xF0 on addresses 0x1000 - 0x100F, 0x1040 - 0x104F, that's 2101 @ 4N
  • replaced 4N now video ram test is OK but having sprite errors, will look at that later as graphic issues are troublesome
  • POKEYS are rusty, sockets are heavily corroded. Pulled one POKEY it basically fell apart (many legs fell off)
  • Other POKEY is bad
  • replaced 40 pin sockets for POKEYS, and replaced POKEYS with NOS POKEYS
  • Sound is messed up, replacing LM324 - no change
  • replaced 7915 - no change
  • replace d555 - no change
  • checking all resistors in sound circuit - OK
  • found that -12 is at GND, there is a short from -12 to GND
  • Found shorted taint cap @ C42, replaced, sound problem fixed
  • There is some gunk all over the edge connector, nothing seems to remove it, used a light sanding block to get it off.
  • looking at sprite circuits again
  • Found a bad @ 8D 74LS163 with logic comparitor, replaced. This returned the missing sprites, (pulling it and running caused sprites to show up on the bottom of the screen)
  • There are still lines through EVERYTHING, both sprites and tiles, so something must be wrong that's common to both circuits.

  • while looking at this the game started coming up with a checked screen
  • RAM test failed
  • looks like bad address selection repalced 74LS139 @ 3e, no change
  • repalced 74LS244 @ 1C/D fixed ram issue
  • back to the video issues
  • tried replacing 74LS273 @ 7J no change
  • 74LS174 @ 6L seemed to have bad outputs, replaced, no change
  • Tested many parts of the video circuits with logic comparitor - no issues found
  • desoldered all 82S25s and put in sockets so I can test with known good 82S25s (7489, 74S289) don't think this is the issue but it's one of the few things I cannot test in circuit and certainly common to both tiles and sprites - no change, put back originals
  • Desoldered and socketed the 932422 - no change, put back original
  • It looks like parts of the graphics are missing
  • replaced 74LS166 @ 7R - no change, put back original
  • Started grounding pins on the video ROM, grounding pins in 5Psimulated the missing pixes and lines, as I got closer to pin #14 the lines got closer to the missing line.
  • rgrounding ping #13 on 5P was one line away, grounding pin #14 showed no change from when it was not grounded
  • validated connectivity from pin #13 on 5P to the two points it runs to, OK
  • pulled 74LS166 5L it tested bad in 2 testers, replaced and video looks normal!
  • Now playing game there is no sound, all mushrooms are on the left and the game restes when you start playing it
  • self test shows both POKEYS are bad (but they are NOS, and they worked before) so there is probably somethign else wrong
  • tested POKEY control input feed by 74LS32 @ 4F, inputs to the chip are OK, but the output is not
  • pulled 74LS32 @ 4F and tested in two testers, it shows bad, replaced!
  • self test shows pokeys are OK, sound works and game plays!
  • High score save circuitry is not working
  • Replaced EAROM
  • High score works, but NOW the video is messed up, looks like atari 2600 graphics!!!

  • Pulled and replaced 74LS166 @ 7R no change
  • testing chips in the grahics circuit common to both the sprites and the tiles (since both seem to be affected) 7P tests OK, but missing with it give similar issues.
  • Grounding address lines for grahics ROMs give similar issues, specifically lines a0 - a2 (or MGA0 - MGA2), found a broken trace @ 6N (not sure how trace got broken all of a sudden... soldered a jumper across the break.
  • Game works!
  • Game Board 33 7/17/2016

    Problem:

    • Game does not boot, lines though screen, moving tiles, constant beeps

    Troubleshooting/dianosis steps:

    • Pulled POKEYS, no change
    • Put POKEYS back in
    • I found when I pushed on socketed 74ls166 @5l lines went away, removed chip socket was all messed worn out and broken.
    • Replacing with new 74LS166 and soldering
    • after pulling 5L, I noticed previous repairs @ 5L and 4M really really bad, many lifted or broken traces
    • replaced scoket and 74LS166 @ 5L
    • Noticed 2101 @ 4M was also replaced, solder work was very bad, after pulling this was even worse than the previous chip.
    • replaced socket and 2101 @ 4M,
    • Trackball is not smooth, like it's jumping both up/down and side/side as you move it
    • Replaced 45848 @ 11P - no change
    • Replaced 74LS74 @ 10R
    • game works!
    Game Board 34 10/01/2016

    Problem:

    • Game does not boot, nothing on screen except maybe some fast shifting white dots/lines
    • Customer has reported game worked for a few hours after he got it then stopped working.
    • Customer reported hearing 3 beeps and had replaced 2101 RAM @ 2H corresponding to the 3 beep code in the manual

    Troubleshooting/dianosis steps:

    • Confirmed 3 beeps
    • Customer solder job looked excellent, no reason to doubt the repair
    • Ran fluke long RAM test @ 0x0000 - 0x3ff - got "data error @ 0" -> more -> data bits 01 never saw that error before
    • Ran fluke long RAM test @ 0x1000 - 0x13bf - same exact result... something is fishy
    • Tried manually reading and writing to RAM 0x0000 and 0x0001 figuring maybe a databus or address bus issue, all writes and reads worked, odd.
    • wanted to further test the address and data bus, so did a ROM test of each ROM with fluke all code roms OK
    • Hmm what could screw with memory on this boards... wait it's got 2 POKEYS!
    • pulled pokeys - game worked!
    • replaced 1 pokey - game works
    • pulled that pokey and put in other pokey - no good
    • put in NOS pokey, game boots fine, test mode is fine
    • Just to ensure everything is OK, did a RAM long tests on the work ram and video RAM
      • long RAM 0x0000 - 0x03FF - OK
      • long RAM 0x1000 - 0x13BF - OK
    • Game works!
    Game Board 35 12/05/2016

    Problem:

    Troubleshooting/diagnosis steps:

    • repaired damage as best I could, installed new socket
    • replaced 74LS245 with customer provided chip
    • game works!
    Game Board 36 5/02/2017

    Problem:

      Static tiles on screen

    Troubleshooting/diagnosis steps:

    • CPU clock OK
    • Reset stuck low
    • Lets go backwards from reset
      • 74LS04 @ 8F is the last chip in the reset circuit, output on #10, input on #11
      • Pin #10 is floating, it is generated from 74LS90 @ 9F pin #11 output , someone already replaced it, testing input pions #5 should be at +5 it is not, going to pull the socket to look for damage, solder job not good, vias damaged, fixed damange, now getting constant reset
      Removed pokeys, no change
    • Fluke bus test ok
    • Ram long 0x0000 - 0x03FF BTS 80, that’s 2114 @ 2e
    • Swapped the ram to see if it switches it does NOT, RAM must be ok, read and write manually to 0x000, 0 and FF, high bit is always stuck, but not changing on looping read, let’s check continuity.
    • 2114 RAMS are directly on the data bus, no buffer, 2E #11 to CPU #26, no continuity
    • Removed socket, there was via damage, fixing
    • Game boots up now
    • Putting back POKEYS
    • Game back to static screen
    • Removed pokey @ 4D, game boots
    • Swapped 4B to 4D, game boots
    • Pokey that was original at 4D was bad, pulled POKEY from other board
    • All 40 pin sockets need to be replaced.
    • Found game resetting with physical movement, ultimately found bad socket work on 9e, 2e and 2f
    • Ended up needing 1 2114 due to damange, 4 sockets and 2 74LS90s due to damage trying to repair
    • Game works
    Game Board 37 05/03/2017

    Problem:

    • Game is dead, no monitor sync

    Troubleshooting/diagnosis steps:

    • /reset is stuck low
    • CPU clock is fine
    • Work backwards from /reset
    • 72LS04 @ 8F input #11 output #10
    • #10 output low, input high
    • 74LS90 @ 9F output #11, input 14 is the main input
    • Output #11 is high, input #14 is low input is /VBLANK which is output from 74LS175 @ 8E pin 3 with #2 should be the opposite, those checkout,
    • 8e has important input on #9 /256H, it is stuck high
    • Let’s verify sync circuits starting with the horizontal syncs @ 6d, 6e, 6f (H)
    • 6D is ok
    • 6e seems bad outputs, replaced new chip had same issue, looks like something is loading it down, pulling up output pins will put back one at a time to figure out what’s loading it down, problem only happens when pin #14 (8H) is attached
    • Need to see what’s on 8H that could be pulling it down, couldn't find anything
    • Replaced 6E, boots up now
    • Needs POKEY
    • Needs new CPU and POKEY sockets
    • Game works!
    Game Board 38 06/24/2017

    Problem:

    Troubleshooting/diagnosis steps:

    • Checked Voltage - OK
    • Checked CPU Clock - OK
    • Checked to make sure reset line is NOT stuck low, it's not, it's transitioning
    • Fluke 9010A bus test, found data bits 5 & 6 are tied
    • Probably a POKEY issue, removed POKEYS, game passes bus test now
    • Still doesn't work, but this now it's doing something
    • RAM short 0x0000 - 0x03FF - OK
    • RAM short 0x1000 - 0x13FF - OK
    • Looked at ROM, found a ROM with 2 pins sticking out, reseated properly
    • Game now boots
    • Put back one POKEY, game went back to static tiles,
    • Put in second POKEY, (with first removed) game boots and self test shows one POKEY bad (since it was not inserted)
    • Switched the POKEY to the other socket, game now detects the other socket as a bad POKEY... good
    • Put in new POKEY for the first one
    • Game works!
    Game Board 39 07/29/2017

    Problem:

    • Game does not work
    • Customer bord #4

    Troubleshooting/diagnosis steps:

    • Pulled both POKEYS - game boots
    • Replaced with new POKEYS
    • Game works!
    Game Board 40 07/29/2017

    Problem:

    • Have a solid blue screen with a quick set of dashes in the center every few seconds, looks like what happens when you have a bad 2114 RAM
    • Customer board #5

    Troubleshooting/diagnosis steps:

    • Found smashed 7915 - replaced
    • Checked voltage, it is good
    • Checked /RESET, it is pulsing
    • Checked CPU clock - OK
    • Fluke 9010A Bus test - OK
    • Checking RAM
      1. RAM short 0x0000 - 0x03FF - BTS 0xF0 @ 0x0000, that is the 2114 RAM @ 2E
      2. Replaced - board boots
    • High score circuit does not work
    • Replced 555 - no change
    • Swapped with new EAROM - no change
    • Replaced EAROM socket, a few pins fell out, now it works!
    • Game works!