13-08-2025, 12:56 PM
I think Roberts may have knobs. I make my own brass inserts.
AFxxx and most Mullard canned transistors have tin whiskers. They can be blown away on the ones with a screen with a charged capacitor once removed from the set. I believe that there are some of other makes that do not have the problem.
Simply cutting the screen can effect a temporary cure.
Just giving them a hard rap often does the same, for a while. Buying new ones is pointless as any old stock will have the same problems.
It is possible to replace them with modern silicon transistors, often without changing the bias resistors.
AFxxx and most Mullard canned transistors have tin whiskers. They can be blown away on the ones with a screen with a charged capacitor once removed from the set. I believe that there are some of other makes that do not have the problem.
Simply cutting the screen can effect a temporary cure.
Just giving them a hard rap often does the same, for a while. Buying new ones is pointless as any old stock will have the same problems.
It is possible to replace them with modern silicon transistors, often without changing the bias resistors.
Boater Sam.
