Asto please don't confuse me with some genius in component identification. Irving is probably in your best ball park for this one. It was an educated guess with the last one and a power of deduction. Looking at the age of the rest of the components I would not even try to repair this...........There are some limits to when you just have to let go of this stuff. To also put something into perspective i worked in there 900/1800 phone division a very long time ago.