Baby Pacman Restoration
- Thread starter Purity
- Start date
PaulSwan said:
Not sure. I've been trying to verify this.
I was under the assumption it was medium res. I was reading the
manual for the K4915 which is all I could find, and which I thought covered the K4900? As the K4800
was the 13" version of the K4900 I thought this was also medium res?
If it is standard res then it does point to a PCB sync issue
Purity2015-09-11 00:17:56
Purity said:
Had a look at the solenoid board today, and the solenoid which I thought was smoking - the left side saucer kickout, had a bad transistor which looks like it has got a bit hot
Ordered a replacement. Hopefully the solenoid is still ok. Will check it out when the new transistor is on the board.Interestingly I found the old advert for the sale of the cab, and it mentioned that the sink holes on both sides were not working. This would definately explain the failure on that sink hole, so I'd better check the other side
Purity2015-09-11 19:20:54
Big thanks to gunblade, who suggested that I should adjust the horizontal hold on the monitor. When I checked this, it was fully clockwise. Turned it down and I am now getting a stable picture for both communications and colour testing screen, which is a massive help, because I can now run some internal diagnostics
So the diagnostics tell me that
1) 3 lamps are out, and they are in really difficult to get to places! There must be a technique to swapping these?
2) The left side saucer kickout is functioning, but the right side is not, although I have checked the transistor for the right side and it was ok. No more smoking with everything plugged in since I changed the transistor
3) There is no communication between the MPU and Vidiot. I need to sort this out before moving forward
But big step forward tonight!
Purity2015-09-12 10:13:25
So the diagnostics tell me that
1) 3 lamps are out, and they are in really difficult to get to places! There must be a technique to swapping these?
2) The left side saucer kickout is functioning, but the right side is not, although I have checked the transistor for the right side and it was ok. No more smoking with everything plugged in since I changed the transistor
3) There is no communication between the MPU and Vidiot. I need to sort this out before moving forward
But big step forward tonight!
Purity2015-09-12 10:13:25
backflipper
Active member
Nice restoration!
Did a bit more work today.
I've managed to replace the three blown lamps, but on powering up the game, the P, and C on the 3rd row were still out.
I checked the schemes and both these lamps fed from the same thyristor on the lamp board, so I removed this component and replaced it with another, and the lamps were now working
HOWEVER, other lamps were now off. Each time I replaced a thyristor (which I did twice) to fix some lamps, others would then be off. So because they keep changing I'm now under the impression that the header pins on the lamp board need replacing.
I think the same is also true of the MPU, because the game actually WORKED twice! I had a couple of games, although certain parts of the playfield are still not working right. Then the third time of powering it up I got communication issues
I then checked the right saucer maze solenoid, and it doesn't look shorted, so I'm baffled why it is not working?
Also whilst I had the playfield available, I noticed that one of the fuses, which should be a 1A, was actually a 10A! I swapped this for a 1A but then most of the lights would not function, so I'm not sure what work has been done here either
Still lots more work to do, but a very good sign that the game was semi-playable at least twice today
Purity2015-09-12 22:22:45
I've managed to replace the three blown lamps, but on powering up the game, the P, and C on the 3rd row were still out.
I checked the schemes and both these lamps fed from the same thyristor on the lamp board, so I removed this component and replaced it with another, and the lamps were now working
HOWEVER, other lamps were now off. Each time I replaced a thyristor (which I did twice) to fix some lamps, others would then be off. So because they keep changing I'm now under the impression that the header pins on the lamp board need replacing.
I think the same is also true of the MPU, because the game actually WORKED twice! I had a couple of games, although certain parts of the playfield are still not working right. Then the third time of powering it up I got communication issues
I then checked the right saucer maze solenoid, and it doesn't look shorted, so I'm baffled why it is not working?
Also whilst I had the playfield available, I noticed that one of the fuses, which should be a 1A, was actually a 10A! I swapped this for a 1A but then most of the lights would not function, so I'm not sure what work has been done here either
Still lots more work to do, but a very good sign that the game was semi-playable at least twice today
Purity2015-09-12 22:22:45
Ok so not posted anything for 4 days
I have now fixed the solenoid issues and the lamp problems.
The solenoid on the right saucer maze had a bad connection on the connector, and I replaced a couple more thyristors on the lamp board, and reflowed a header and now I have all lamps fumctional on the playfield
I just need the communication sorting now, get some of the switches working and I'm in business!
Purity2015-09-16 20:53:03
I have now fixed the solenoid issues and the lamp problems.
The solenoid on the right saucer maze had a bad connection on the connector, and I replaced a couple more thyristors on the lamp board, and reflowed a header and now I have all lamps fumctional on the playfield
I just need the communication sorting now, get some of the switches working and I'm in business!
Purity2015-09-16 20:53:03
You're making a monumental effort on this. can't wait to see you get this fully working
Replaced a couple of the MPU pin headers tonight and the game is working. Initially I thought most of the switches were not working, as they don't seem to be registering in test mode, but they seem to work fine in-game apart from one switch
I still need to replace the two connectors on the MPU, as they are corroded, get the spinners repainted and new graphics on, and get the switch working and it should be sorted
I still need to replace the two connectors on the MPU, as they are corroded, get the spinners repainted and new graphics on, and get the switch working and it should be sorted
Finally this is 100% working. I renewed the connectors on the MPU, not perfectly but better than the corroded pins that were on there.
The switch on the tunnel lane was still not working, so I had a look under the playfield, and checked the diode which was fine, then I noticed something really obvious. The switch was permanently on, so it registered once and that was it. I careful prized the switch contacts apart so that they weren't touching and the lane switch is now working fine.
Although there are a few minor things I need to do on this I'm now classing it as finished
The switch on the tunnel lane was still not working, so I had a look under the playfield, and checked the diode which was fine, then I noticed something really obvious. The switch was permanently on, so it registered once and that was it. I careful prized the switch contacts apart so that they weren't touching and the lane switch is now working fine.
Although there are a few minor things I need to do on this I'm now classing it as finished
