OK - i have replaced 3 x TIP122 transistors and as suggested - all the 2N4401's were OK when tested out of circuit.  A few resistors were also replaced.

I went and checked the resistance of all the coils - any that had a resistance lower than 2.5 ohms (suggested by pinrepair) i pulled completely out of circuit and tested again.

1 has zero resistance

1 has 1.6

1 has 2.3

Tested the diodes (out of circuit) and they are all OK

Should i replace all three of these coils? (Two of the  blown transistors were driving the 1st two coils listed above)?

Thanks

Rob