13-10-2015, 03:38 PM
(21-09-2015, 09:07 AM)sportiva62 Wrote: Hi have just purchased a Roberts R500,(not working), when it arrived to my dismay it had a missing transistor !(af 115) think its TR1(first on the left side of the pcb just above the speaker at about 10 am position, does anyone know the relative positions for collector ,base,emitter & screen when looking from the back of the set,think it might work better if it in there!
thanks Roger.
Maybe Mark will post a link to the article he did on fixing AF117's?
I'd say your best bet would be to contact Langrex who sell the AF117's (they are under a fiver). You could then test it or get them to test it before purchase (possibly follow Mark's AF117 voltage application).
Later, I'd be very interested to follow on from this topic with regard to these transistors as I sort of came a cropper over the AF117's. I have a Bush tranny that I plan to go back to work on in the future and I may buy a new AF117 as I feel these are a far hardier transistor than is appreciated. Sure, they can become defective but not all of them do and, besides, the problem can be fixed with care.
I have an early sixties car radio with all AF117's and it works fine. Not bad for a radio that's over 50 years old.
