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Yes i’ve got the printed schematics. really handy to have them.
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Complete Cosmic Gunfight
- Thread starter AlanJ
- Start date
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Ps the ram chip soldered on the board. ill sort the power supply first then get back onto the mpu board
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The 5V power issue isnt the Bridge rectifier, It also drives the 12v line and that is working fine, so I need to hone in on the rest of the 5v circuit.
Ive replaced Q5 with a known worker from another board, replaced C14, C12 on the output. BR1 ok as the the 12V line works well under load.
I'll check the reference voltages around IC1
Ive replaced Q5 with a known worker from another board, replaced C14, C12 on the output. BR1 ok as the the 12V line works well under load.
I'll check the reference voltages around IC1
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Checked out the BR some more. it can take a good load of power, so I don’t think it’s that. I’m sure I can get a working board out of the two I have.
Next the MPU board. Wont boot.
Started at 7.30 am. Still going on it at 7pm.
Followed all the pinwiki advice and tests.
Decided to make new roms as the old ones looked well tarnished. So first job to convert U17 slot from 2532 to 2732 eprom config. Fairly easy
I’ve only got 2732’s. so presumed I can double the 2k 2716 images for the 3 other roms??
Anyhow still no boot. double checked the flipper roms. they look fine.
So decided to go down the route of the test roms, so created some of those test roms too
First one, the led test failed. so did the flipper relay in the solenoid test- which is recommended to try if test 1a fails.
Looks like 6821 PIA is at fault. So took that off and socketed and put in a new one.
Still no joy. A few test probes on the 7 segment driver ic, looks like that is faulty too. so another replaced and socketed chip. the bcd to 7 seg chip is an odd one. i had an almost similar one. but it’s output is inverted so the 7 segment display will light as an inverted number! not ideal but will get me through this stage, hopefully.
Now suspect the line driver buffer drivers around the data and address lines to/from the mpu. they need a good testing out.
I’ve also put in a brand new 6808 cpu.
Next the MPU board. Wont boot.
Started at 7.30 am. Still going on it at 7pm.
Followed all the pinwiki advice and tests.
Decided to make new roms as the old ones looked well tarnished. So first job to convert U17 slot from 2532 to 2732 eprom config. Fairly easy
I’ve only got 2732’s. so presumed I can double the 2k 2716 images for the 3 other roms??
Anyhow still no boot. double checked the flipper roms. they look fine.
So decided to go down the route of the test roms, so created some of those test roms too
First one, the led test failed. so did the flipper relay in the solenoid test- which is recommended to try if test 1a fails.
Looks like 6821 PIA is at fault. So took that off and socketed and put in a new one.
Still no joy. A few test probes on the 7 segment driver ic, looks like that is faulty too. so another replaced and socketed chip. the bcd to 7 seg chip is an odd one. i had an almost similar one. but it’s output is inverted so the 7 segment display will light as an inverted number! not ideal but will get me through this stage, hopefully.
Now suspect the line driver buffer drivers around the data and address lines to/from the mpu. they need a good testing out.
I’ve also put in a brand new 6808 cpu.
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Hi Yes Ive changed 2 out of the 4 so far, but still got issues. After a few more hours today I've figured out that there is a short to ground on one of the data bus lines D7 is always low.
That data bus of course goes all around the mpu board to lots of chips, so going to take some tracking down!
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Found the short. under one of the rom sockets. D7 runs next to Gnd on pins 17 and 18 so it was fairly obvious place to look. but of course several rom sockets to look at.
I’m now going to see if i can get the test rom working, then hopefully insert the 4 proper roms one by one (i want to see if the 7 seg led shows the correct diagnostics)
I’m now going to see if i can get the test rom working, then hopefully insert the 4 proper roms one by one (i want to see if the 7 seg led shows the correct diagnostics)
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Hi Shaun, i didn’t take a pic sorry.
Now I can get the 01a test rom to work. it’s counting up the 7 segment display and flashing the 2 indicator leds.
I’ve powered on and off several times and all working consistently well. Looking good. Will now try the flipper roms ICs 17,20 and then the game roms 14,26. I’ll try one at a time.
Now I can get the 01a test rom to work. it’s counting up the 7 segment display and flashing the 2 indicator leds.
I’ve powered on and off several times and all working consistently well. Looking good. Will now try the flipper roms ICs 17,20 and then the game roms 14,26. I’ll try one at a time.
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Hmm, still not booting properly. Got the oscilloscope out now. It’s getting serious 
For a bit of light relief I broke off to take another look at the power supply board. The problem points to the power regulator transistor. But even a good one from another board doesn’t work, really odd. The other components in the circuit all to spec and I measured the voltages around the regulator ic and they all good.
Then I noticed the issue. A bad connection to the power transistor. one if the wires under the heat sink isn’t making good contact.
Removed the heatsink and resoldered it on properly. 5v now giving out plenty of power!
No wonder it died under the tiniest load before.
So that’s a relief
Back to the MPU ......
For a bit of light relief I broke off to take another look at the power supply board. The problem points to the power regulator transistor. But even a good one from another board doesn’t work, really odd. The other components in the circuit all to spec and I measured the voltages around the regulator ic and they all good.
Then I noticed the issue. A bad connection to the power transistor. one if the wires under the heat sink isn’t making good contact.
Removed the heatsink and resoldered it on properly. 5v now giving out plenty of power!
No wonder it died under the tiniest load before.
So that’s a relief
Back to the MPU ......
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MPU looking good.
Inserted first game rom - ic 17 - it shows error 5 - IC 20 Rom fail, so
inserted rom ic 20 , then it showed error 6, ic14 game rom error, so
inserted rom in 14, then it showed error 7 ic26 game rom error, so
inserted rom ic 26 then it showed error 8, but then seemed to be error 0.
So, I hooked up the driver board to the mpu board., it then flashed a zero and the 2 leds, then they all go out. So looks like it's happy with its boot tests and all the new roms I've put in.
Tomorrow I'll try installing it in the game, along with the repaired power rectifier board and then gradually connect up various parts - GI, then lamp matrix, then displays, then solenoids.
Inserted first game rom - ic 17 - it shows error 5 - IC 20 Rom fail, so
inserted rom ic 20 , then it showed error 6, ic14 game rom error, so
inserted rom in 14, then it showed error 7 ic26 game rom error, so
inserted rom ic 26 then it showed error 8, but then seemed to be error 0.
So, I hooked up the driver board to the mpu board., it then flashed a zero and the 2 leds, then they all go out. So looks like it's happy with its boot tests and all the new roms I've put in.
Tomorrow I'll try installing it in the game, along with the repaired power rectifier board and then gradually connect up various parts - GI, then lamp matrix, then displays, then solenoids.
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Thus morning i installed the mpu , driver and power board
A load of testing to ensure psu voltages all correct, then applied power to the mpu and driver board
It booted! no error lights. diag button reported “9” with coin door open. as expected
Plugged in the gi, then the displays, feature lights, sound and then solenoids. all looks ok.
can’t clock credits or start a game but can get into test mode. displays all work, sound works.
some solenoids firing
not many switches working.
Switch test showing that all rows appear ok as i have a full set in column 6 and 7 oh and some col 5. col 8 not used. problem is noting on cold 1-4. which has all the coin slots and start button!
traced circuit. looks like faulty pia or more likely 7406 ic. changed pia. same. not got a 7406 but 7404 in my spares. popped that in as a temp trial and hey presto. a lot more switches working
I clocked up some credits and managed to start a game.
there is no ball eject mechanism:
but manually firing the ball over to the righ of the trough does end the ball
Phew weee. looks like i’ve got a working game.
Now i need to sort out the missing parts on the playfield :
no outhole kicker
no plunger
missing parts on middle drop target - no plunger or reset plate
no left flipper coil or parts
left slingshot not working
top right pop bumper not working
and probably loads of other stuff......
A load of testing to ensure psu voltages all correct, then applied power to the mpu and driver board
It booted! no error lights. diag button reported “9” with coin door open. as expected
Plugged in the gi, then the displays, feature lights, sound and then solenoids. all looks ok.
can’t clock credits or start a game but can get into test mode. displays all work, sound works.
some solenoids firing
not many switches working.
Switch test showing that all rows appear ok as i have a full set in column 6 and 7 oh and some col 5. col 8 not used. problem is noting on cold 1-4. which has all the coin slots and start button!
traced circuit. looks like faulty pia or more likely 7406 ic. changed pia. same. not got a 7406 but 7404 in my spares. popped that in as a temp trial and hey presto. a lot more switches working
I clocked up some credits and managed to start a game.
there is no ball eject mechanism:
but manually firing the ball over to the righ of the trough does end the ball
Phew weee. looks like i’ve got a working game.
Now i need to sort out the missing parts on the playfield :
no outhole kicker
no plunger
missing parts on middle drop target - no plunger or reset plate
no left flipper coil or parts
left slingshot not working
top right pop bumper not working
and probably loads of other stuff......
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I did a test with the switches rows and cols unplugged and tested each row and col. Found that cols 1-4 are out, and that led me to the duff IC, replaced and all seem to be working. One or two odd switches may be out - but I suspect they are physical problems now.
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PS - The sounds on this are brilliant. Can't wait to have a proper game!
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I deffo need one of those backglasses !
And you're right. The sounds on it are class. Very Williams but thats just fine in my book
And you're right. The sounds on it are class. Very Williams but thats just fine in my book
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ill put you in touch with the guy in holland
I'm curious to see how you get the artwork back on the sides of the backbox. No prizes for guessing why. (Watches with baited breath )
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Morning!I'm curious to see how you get the artwork back on the sides of the backbox. No prizes for guessing why. (Watches with baited breath
I'll use these
http://pinballpimpstencils.com/cosmic-gunfight/
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As I’m nearing the end of the other big project, I decided to have a look at this project again today.
First check was to ensure no sign of woodworm. There isn’t
. I had a good look over the whole cab and backbox. Looks like it’s all gone as i cut out the wormed part of the backbox and replaced.
I replaced the missing plunger and reset plate on the central drop target.
I replaced the missing plunger and link and spring on the left flipper.
Refitted the loose coil end stop on the outhole lane (had to pinch a screw off another mech until i get some spares)
Tested machine still boots - it’s been sat in the garage for two months. It booted okay. Started a game and tested a few of the mechs. pops ok but something blew a couple of fuses. I think it was the left sling shot. Coil tests out ok, but i then decided to test all other coils. they all seem ok so not sure what caused the issue.
Ball eject into the shooter lane is not strong enough so that needs looking at.
Tomorrow I’ll strip and clean the playfield. It’s blooming really filthy.
I’m excited to get this machine playable. I splashed the cash on a new mirrored backglass a few weeks ago:
First check was to ensure no sign of woodworm. There isn’t
. I had a good look over the whole cab and backbox. Looks like it’s all gone as i cut out the wormed part of the backbox and replaced. I replaced the missing plunger and reset plate on the central drop target.
I replaced the missing plunger and link and spring on the left flipper.
Refitted the loose coil end stop on the outhole lane (had to pinch a screw off another mech until i get some spares)
Tested machine still boots - it’s been sat in the garage for two months. It booted okay. Started a game and tested a few of the mechs. pops ok but something blew a couple of fuses. I think it was the left sling shot. Coil tests out ok, but i then decided to test all other coils. they all seem ok so not sure what caused the issue.
Ball eject into the shooter lane is not strong enough so that needs looking at.
Tomorrow I’ll strip and clean the playfield. It’s blooming really filthy.
I’m excited to get this machine playable. I splashed the cash on a new mirrored backglass a few weeks ago:
Interested in seeing how your PF compares to mine. Mine isnt especially bad - but there is wear for sure. (And one significant blemish )
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Started 5:30 this am on the playfield strip and clean
Used magic eraser and IPA to get the swirls out:
Lots of stuff being washed and cleaned
New star posts and lane protectors:
Metal being rust treated, cleaned, polished, some in the tumbler.
I’ve started checking and replacing bulbs. GI is going warm white LED. leaving features as Indandescent.
The top playfield GI all out, found a loose connection under the pf.
Quite a lot of feature lights out. but not the bulbs. When i checked manual it looks like lamp matrix rows 7 & 8 out.
Missing transistor on 8, but 7 tests ok (how did i miss a missing transistor???).
Rows 1-6 work and are controlled by a hex buffer chip, rows 7-8 controlled by a different hex buffer chip, so will be that:
socketed and replaced
I plugged it in and all feature lights sparked into life! yey!
Still can’t figure out why the right pop doesn’t work??? will investigate that next.
Used magic eraser and IPA to get the swirls out:
Lots of stuff being washed and cleaned
New star posts and lane protectors:
Metal being rust treated, cleaned, polished, some in the tumbler.
I’ve started checking and replacing bulbs. GI is going warm white LED. leaving features as Indandescent.
The top playfield GI all out, found a loose connection under the pf.
Quite a lot of feature lights out. but not the bulbs. When i checked manual it looks like lamp matrix rows 7 & 8 out.
Missing transistor on 8, but 7 tests ok (how did i miss a missing transistor???).
Rows 1-6 work and are controlled by a hex buffer chip, rows 7-8 controlled by a different hex buffer chip, so will be that:
socketed and replaced
I plugged it in and all feature lights sparked into life! yey!
Still can’t figure out why the right pop doesn’t work??? will investigate that next.
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Pop bumper not firing was missing a power transistor and drive transistor!!!! Replaced and all working fine.
how did i miss this? careless:
But then disaster. I noticed the sound had gone off for some reason. West into the diagnostics menu and as it came out of lamp test I noticed most of the feature lights stuck on.
Power cycled the whole machine. Boots ok but all these lights now permanently on????
On closer examination it’s lamps on rows 1-6. Seems odd as they were working, and i replaced the IC earlier that controls rows 7-8. It looks like the other IC is dead.
Anyhow I decided to check to see if it’s the PIA or the chip. The output of the pia looks wrong, not pulsing. so i cut pin one of the other chip that connects to pin 4 of the pia. that pin on the pia now pulses properly, so deffo the hex inverter chip.
Interestingly this is the 3rd chip of that type on the driver board that is faulty.
Replaced it and socketed it - Lamps all good again (for now!)
Sound card. I turned the remote volume up,and can hear speaker hum, so the audio circuit seems good. checked board voltages. getting +12, -14, +5.02, so all three are ok.
Cpu chip seems to be pulsing some of its data and address lines. However the chip looks discoloured in the centre. I’m gonna try a new one first, If I can find a spare. I think i used the last one on the 8 ball deluxe sound card. I might have one on a spare board somewhere.
how did i miss this? careless:
But then disaster. I noticed the sound had gone off for some reason. West into the diagnostics menu and as it came out of lamp test I noticed most of the feature lights stuck on.
Power cycled the whole machine. Boots ok but all these lights now permanently on????
On closer examination it’s lamps on rows 1-6. Seems odd as they were working, and i replaced the IC earlier that controls rows 7-8. It looks like the other IC is dead.
Anyhow I decided to check to see if it’s the PIA or the chip. The output of the pia looks wrong, not pulsing. so i cut pin one of the other chip that connects to pin 4 of the pia. that pin on the pia now pulses properly, so deffo the hex inverter chip.
Interestingly this is the 3rd chip of that type on the driver board that is faulty.
Replaced it and socketed it - Lamps all good again (for now!)
Sound card. I turned the remote volume up,and can hear speaker hum, so the audio circuit seems good. checked board voltages. getting +12, -14, +5.02, so all three are ok.
Cpu chip seems to be pulsing some of its data and address lines. However the chip looks discoloured in the centre. I’m gonna try a new one first, If I can find a spare. I think i used the last one on the 8 ball deluxe sound card. I might have one on a spare board somewhere.
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pic of the sound card 6808 cpu chip.
