Pinballs

We haven't talked much about some of the flippers that we have had for quite a time. Dolly Parton is one of those. Truth be told, we didn't forget it, but repairs on this machine went relatively smoothly. We have to confess having slightly "cheated" though, see below ;)

Here's a quick summary of what happened in the past months:

First checkup when the machine arrived: all the boards have been cannibalized, and many components are missing, in particular the CPU and accompanying PIAs on the MPU board. First step: replace all missing components. On the solenoid driver board, U4 (CA3081) has been replaced. Missing transistors have been replaced with TIP102. C23 has been replaced with a 15,000 µF 25V. All the capacitors on the MPU board have been replaced as well (like what we did on the KISS), as well as some IC sockets (oxidized). On the rectifier board, all 3 rectifying bridges have been replaced, as well as R2 (dead) and a Molex connector (burnt).

At this point, the MPU board wasn't functioning yet. We then did the reset circuit modification using a DS1811 (as for the KISS, following instructions from pinrepair). We also replaced U12 (555), U16 (9602), U19 (4011) and U16 (74LS37), their output levels didn't match the specifications. First flash ;-)

We then modified the MPU board so that it would accept 2732 EPROMs, and used a test EPROM to check part of the operation of the board. 6 flashes, the board now boots properly. We then programed Dolly Parton 2732 EPROMs, and put the board back in place.

On the lamp driver board, we replaced the missing 2N5060 and TIC106 triacs. We then put everything back in place for a first test. The MPU board showed signs of instability. We then decided to replace it with a spare -35 modified to use a 6802 instead of the 6800/5101, and a single 2764, until we investigate further the -17. This where we "cheated" ;-)

At this point, almost everything works, except the blinking lights. Replacing the 4514 decoders fixed that last issue. One display has apparently suffered from high voltage abuse and needs to be replaced, the other ones (except Player 1) have the last digit (units) blinking slightly.

After a final cleanup, the machine is finally ready to play, and we had some fun playing it for a while before we had to part with it regretfully ;-)

Pictures of the finished machine here: