J.D brought the boards back to me to test after the faulty diode.
Both pre-driver and tip102 tested good on the bench , i then put them on the test bench and all solenoids fired as they should...also all switch columns and rows are working properly.
The test bench has never lied to me so far , but that doesn't mean it can't happen.
Before that when he first brought the boards to me with the blown transistor , i replaced the pre-driver , driver transistor , and the 7408 chip and put it in a socket.
If you want J.D i can lend you another pair of boards ,Driver and Cpu and that way if you put them in you can be sure where the problem lies.
Could the 7402 chip be faulty?
This chip is closer in circuit to the coil than the 7408 chip, so if the 7408 chip was no good I would expect this chip to be stuffed too.
My Timewarp had a similar problem where all the other coils on the 7402 chip worked fine but one didn't, changed the chip and away it went.
