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Old 11-12-2024, 08:12 PM
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vol.2 vol.2 is offline
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fdt-5bx5 Violently Exploding Capacitor

So, I got my little Watchman back with a raster, and I went about trying to set it up only to notice that the horizontal was quite shifted to the left.

I remembered that it was like this before I mothballed it a couple years ago, and there was some kind of an issue.

So I didn't know exactly what to do because there's no HOR Shift on this set, so I just set it up the best I could and kind of stretched the screen a little bit.

After it had been on for awhile, I was tweaking the purity and all of a sudden the image collapsed horizontally and a capacitor blew up inside the set.

It was C516, a 3.3uF bipolar cap, which was directly in line with the horizontal linearity coil leading to the yoke.

The service manual says the HOR yoke windings should be 0.5ohms, and I read 1ohm, so I think it's fine. I measured it and moved around the yoke and fiddled with it and the reading did not change at all, so I don't think there's a dodgy short.

Here's a picture of the cap and it's location, the part of the service manual showing the blown up cap, and a picture of the raster from before the cap blew up.

If you look at the picture, you can clearly see that the raster was pretty messed up as the circles on the right side are much smaller than the ones on the left; the horizontal linearity was all messed up, and no amount of moving the yoke helped it.



I don't think it was the capacitor's fault because I'm pretty sure it was already replaced by me. It's possible this happened before and I just forgot about it. It's been a long time since I tried to work on it.

Any thoughts?





Last edited by vol.2; 11-12-2024 at 08:55 PM.
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