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
