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Old 12th Aug 2006, 6:52 pm   #17
Tom_I
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Join Date: Jul 2006
Location: North Herts. UK.
Posts: 549
Default Re: Are AF11*'s repairable?

OK, here's the continuing saga.

The first photo shows the innards after the old silicone grease had been removed. I gave it a quick spray with contact cleaner, but didn't attempt to remove every last vestige of the old grease. I then potted the works in new silicone grease (just ordinary Servisol stuff from Maplins) as shown in the second photo, refitted the can and ran a soldering iron round the rim to tack it all back together.

I don't have any fancy test equipment, but the junctions tested OK with a multimeter. Earlier I described this transistor rather carelessly as "dud". It was internally shorted between the can and one other connection - I forget which. Anyway, it now seemed OK, but to prove the pudding I got out a donor set - an old Murphy Transistor 7 with a wrecked case but working chassis. I removed the most accessible of the AF117's and substituted my repaired one (and I did connect all four leads - no cheating). The set burst into life when I connected a battery, and seemed to work perfectly.

So the answer to David's original question is yes - they can be dismantled and dewhiskered. How long the repair will last is unknown, and whether it's actually worth doing is a matter of opinion.....

I should emphasise that there's nothing original in what I have just done - I'm repeating what has been done before in the post which I mentioned a few messages back. However, it's a good scientific principle to repeat and confirm other people's findings.

Cheers for now.

Tom
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