21-09-2015, 10:19 AM
Roger, you're probably aware that the AF11x series of transistors suffers from tin whiskers. These short out the electrodes. The subject has been covered many time both here and elsewhere. In summary:
Both old and NOS parts suffer from the whiskers
Cutting the screen lead will often give a rough and ready cure
It's sometimes possible to fix them by either blasting the whisker with a battery or by opening the case
You can replace the AF11x with AF124 or AF125 but these are starting to get more expensive now
Some people have reported successful replacement with low cost silicon devices such as the BC558 though the bias might need to be tweaked
Both old and NOS parts suffer from the whiskers
Cutting the screen lead will often give a rough and ready cure
It's sometimes possible to fix them by either blasting the whisker with a battery or by opening the case
You can replace the AF11x with AF124 or AF125 but these are starting to get more expensive now
Some people have reported successful replacement with low cost silicon devices such as the BC558 though the bias might need to be tweaked
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
