70's Kiss!

[The seeker]

Hi folks back again this time with a kiss. Back story... local man was oldies king with a friend who asked if I could take a look his pinball machine. I say yes out of curiosity turns out it's a tidy kiss. Game fires up gi works. No ball eject and dodgy sound issues. He forced me to take it home and see what I can do. First I drilled the lock tool the glass off started a game - I had to manually put the ball in shooter lane. I was pleasantly surprised when the game played almost 100 % all drops perfect scoring and targets all 100% . Sound is good , music is bad. And ball won't eject.. I'll be doing solinoid test later today. My suspicion is a rotting mpu. Anyone had any experience with kiss / 70's Bally any tips to try? Tnx

 

[Jay Walker]

Hi,

If the out-hole solenoid doesn't work in the solenoid test either, check the coil return circuit. Basically, by-pass the electronic stuff using a jumper wire to ground. Starting at the coil itself, identify the return terminal (it'll have the plain end of the diode connected). Take a jumper wire, connect to the ground braid inside the cabinet and then momentarily touch the wire to the return terminal. If the coil is okay, and has a live feed, it should operate. If so, trace the return wire back through the playfield wiring to the solenoid driver board, then to its drive transistor package (it's okay to use the metal tab of the transistor as a test point). The rule of only grounding the return briefly applies throughout.

If the return circuit is alright, then the solenoid driver could be faulty - its large chip is a decoder, which interfaces with the Mpu board, and controls the solenoid transistors via the three small chips, which are simply seven transistors built into one chip as an array. If you have a schematic for the driver board, it'll show which drive transistor and array chip are used for the out-hole solenoid. There are test points on the driver board which allow test operation of the drive transistors and array transistors, by pulling their 'base' terminals up to 5v; it's important to use these if you wish to check the devices from the 'computer' side.

 

[The seeker]

Couple of snaps I have on my phone ..

 

[The seeker]

An update , just had the back box open . Gave the connectors a re seating ... boom sorted ! I still can't tell if the sound is bad or if the music for the game is rubbish ?

 

[chris b]

Sound is rubbish