Broken rheostat on Mac SE

[Ttpilot]

The display on my SE sits at the right edge of the screen. I was going to shift it left and discovered the little adjusting screw in the rheostat is missing. Is there a way to fix that short of replacing it? The display is completely usable as is, but it looks off center

 

[codevonlux]

Shifting image on the CRT for SE is done by adjusting/rotating the metal tab on the neck of the tube. Width adjusting is by core of an inductor coil. None of them is a rheostat.

 

[Ttpilot]

So it is. Thanks. In any case the little adjustment screw is gone on the [checks notes] width inductor coil

 

[codevonlux]

Any photo? Hard to imagine which part you are referring to (little adjustment screw) thanks.

 

[Ttpilot]

Any photo? Hard to imagine which part you are referring to (little adjustment screw) thanks.

This one

 

[codevonlux]

As you can see in the photo. There is no “screw” in the coil. You can just use a hex tool (you must not use metal tool when powered on otherwise the tool will get hot and burn your hand). I normally use a trimmed q-tip for this adjustment. You will notice the black part I marked in the photo to extent in and out the red wire coil. Hope this helps

 

[codevonlux]

If the black part is missing in your case, maybe someone in this forum can spare one whole part?

 

[mmmlinux]

You also dont want to use a metal tool because it will affect the inductor you are trying to tune.

 

[Ttpilot]

You also dont want to use a metal tool because it will affect the inductor you are trying to tune.

I have a non metal tool. Unfortunately, there is no screw/thingie to adjust on that particular control

 

[makerorama]

Hi. Did this ever get resolved? I seem to be facing the same problem. I have just recapped my SE/30 and the picture is a bit too wide. I went for the width adjustment, but it seems its just an empty hole. I would expect to see a screw or something in there for me to turn with a plastic tool and adjust the width.

 

[powellb]

Hi. Did this ever get resolved? I seem to be facing the same problem. I have just recapped my SE/30 and the picture is a bit too wide. I went for the width adjustment, but it seems its just an empty hole. I would expect to see a screw or something in there for me to turn with a plastic tool and adjust the width.

It is hard to see with your eye (your picture is likely masked in that black area), but on the side facing the analog board is a hex shaped opening a little bigger than the hole you are seeing light through. You need to use your hex driver (if metallic, adjust while off, test, repeat).

I have a problem that I am not sure what to do about: my horizontal width inductor is there, I can adjust it, but it makes no difference. The horizontal width on my SE/30 is blown out (it is missing the left and right regions of the screen). No matter the amount of adjustment changes it...

EDIT: Reading more, DO NOT use the metal hex driver as I said above (even when off). The ferrite is extremely brittle and you can break it. This is a nice article that shows how to use a plastic straw and plastic hex to adjust it: Adjusting Width Coils

 

[makerorama]

It is hard to see with your eye (your picture is likely masked in that black area), but on the side facing the analog board is a hex shaped opening a little bigger than the hole you are seeing light through. You need to use your hex driver (if metallic, adjust while off, test, repeat).

I have a problem that I am not sure what to do about: my horizontal width inductor is there, I can adjust it, but it makes no difference. The horizontal width on my SE/30 is blown out (it is missing the left and right regions of the screen). No matter the amount of adjustment changes it...

EDIT: Reading more, DO NOT use the metal hex driver as I said above (even when off). The ferrite is extremely brittle and you can break it. This is a nice article that shows how to use a plastic straw and plastic hex to adjust it: Adjusting Width Coils

Thanks for the link. I now believe that in my case, the adjustment knob "core" actually fell apart while taking the computer apart. I found this small black threaded rod on the floor near where I disassembled the machine. I wasn't sure where it came from and thought it was for the chassi, but I now believe it goes into the width adjustment knob in between the coils. I haven't taken the time to disassemble the machine again. I am waiting for a BlueSCSI adapter to arrive. As soon as it does, I will open up the SE and take a look.

 

[powellb]

Actually, it looks like it might be mostly intact. You should be able to carefully thread it back into the housing. It is going to take trial and error to get the horizontal size set. Once you do, you might try putting a little dab of hot glue in to hold it in place (I don't think the hot glue should affect its inductance, but I could be wrong).

I have been looking for a donor part for mine. I finally found a parts Mac Plus board I ordered. Will see if that one is in good shape, and I can replace mine.