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Find replacement line filter LF2 that has battery damaged legs

dklawren

New Member
Joined
Mar 1, 2021
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4
I recently acquired a Macintosh 512k and when cleaning the analog board, I noticed that battery had leaked down and ate off a couple legs from the line filter. It is labeled LF2 and it is connected to the AC plug port. I have removed it to see how much damage and I don't think I can fix the legs has they have corroded nearly flush. Is there anywhere that sells drop in replacements (has 4 prongs from the bottom) or a way to construct something similar that would work? Thanks!
 
From the description you made and the silk screen "LF2", I would guess that it's a transient filtering double choke.

If the legs are corroded off, you could try to pick the ends of the copper wires out of the bottom and attach new legs to it. If you can't attach new legs, the value of the choke isn't terribly important. You could harvest one from a dead power supply and transplant it in.

If you need to test the analog board, you can just jump the choke out with jumper wires. Just be VERY sure that you have the jumpers in the correct position, to make continuity from hot to hot and neutral to neutral, and not hot to neutral. If you go hot to neutral, it will blow up when you plug it in.

It would be helpful if you took some pictures of the choke and the top and bottom of the analog board where it sits, that way we could determine the orientation it's supposed to be in.
 
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