ok after a day of playing here is where im at....
at the magnet driver board the yel/vio reads 78 v same with the blu so my guess thats ok as book says 50+
at the blu/wht 18 gauge at magnet driver plug i have no or very little power.. maybe 1v...
followed wire back to display board.... here i have 5v from the orn/yellow,5v from the blu/wht 22 gauge and 5v from the wht/brn/blk.
thought must be one of the q4 q5 q6 transistors as when i put a multimeter to them power was going through them all differently so changed all 3.
when i connect the magnet driver board same thing... magnet switches straight on!

any ideas what to test next?

did you replace Q3 again? it's probably cactus again.

on the blue white wire between the two boards you should have either 0 volts (when the magnet is supposed to be off) or +5 volts (when the magnet is supposed to be on) anything in between then you will overheat Q3

I would be replacing c4 if it is a 1uf tantalum capacitor.

It's time to make a test led. Add a 150 ohm resistor to the led leg on the flat side then connect the other leg of the resistor to J2 pin 13 (GND / Black) and the long leg to J2 pin 15 (blue/white 18 gauge)
you want to make sure you have Q3 disconnected, we want to check if the display board is working or not.

I assume there is a test to check the magnet in the diagnostics?
if there is then run the test, The test led should light when the magnet is supposed to be activated and turn off when the magnet is supposed to be turned off.

Let me know how you go.