As has already been noted in this forum, the motor on the KA-33 radio fan is appallingly constructed, looking like it was assembled by a five year old in a blindfold – see here.
Anyway, ours had died, and looking inside the metal can (which can actually be removed quite easily without damage by slicing off the little plastic pips on the top of the can with a razor blade and pulling gently) showed the problem.
Ironically, there is almost no provision for cooling the electronics of the fan designed to cool the electronics! You can clearly see one of the power Darlington transistors is fried.
Replacing both TIP111 transistors was no problem – less than a couple of quid from a certain online auction site, but I couldn’t bring myself to reuse that circuit board. There’s enough room above the board to bolt the transistors to the inside of the metal lid (with a TO220 mounting kit) and connect to the circuit board using wires, for at least some heat sink effect.
If anyone else wants to have a go, I have nine of the pcb’s left over – 10 was the minimum I could order!
That’s a very nice job, and welcome to EuroGA 
I know nothing about electronics but the state of the orginal is shocking.
