SE/30 ferrite core missing preventing horizontal CRT adjustment?

[geerlingguy]

I picked up an SE/30 last year at VCF Midwest, and I procrastinated until this week to even test it out. Mostly works, has a new ROM SIMM, has 20MB of RAM, yadda yadda. So far I've:

• Added a BlueSCSI v2
• Set up System 7.5.5 with MacTCP and an Asante network card for networking (Netscape 2.0 works a treat!)
• Replaced the rattling fan with a Noctua 60mm 12V fan using the spare Molex 4-pin connector (the fan mount screws were practically cemented in place! That loctite lives up to its name!)
• 3D printed an LED mounting plate and stuck a yellow LED behind the lens, and attached it to the BlueSCSI LED headers (works great!)

But when I went to tweak the CRT picture, the vertical adjustment, luminance, and focus were fine (focus is a little flaky, but works), but the horizontal adjustment... it was just missing. Like I can see right through that adjustment port to daylight on the other side!

It's a weird adjustment, to be fair... according to my Googling, it was a threaded ferrite core? Maybe got shattered by someone going a little ham on it? How can I replace that so I can get back some horizontal adjustment?

Here's a picture from the top:

 

[ESM-NL]

Nothing is missing. That black core inside the plastic tube is the adjustment. Just use a 2.5 millimeter hexagon wrench made of plastic (an iron one gets hot).

 

[geerlingguy]

Just use a 2.5 millimeter hexagon wrench made of plastic

Oh I've never had one of those! I'll have to find a plastic bit set or maybe even 3D print one... I did notice it looked like a hexagonal shaft inside. Maybe I should look up the SE/30 repair manual before I post here next time, heh.

 

[warmech]

Not saying buy these, just providing an example: wrenches. Those are pretty expensive for a set of adjustment tools and I'm sure someone has made a printable set by now. I have a few disparate sets of these in nylon from decades ago that I use on the RGB monitors in my arcade cabinets to adjust their width coils. Like ESM-NL said, don't use a metal one; two reasons on that. One, if used while it's powered on the adjustment coil turns into an induction coil, lol, and it does get hot. Two, the ferrite cylinder in there is actually rather fragile; a metal wrench stands a decent chance of cracking and/or disintegrating it. Ask me how I know that...

If you do print one (it is literally a 2.5mm hexagon, lol) and the coil is hard to turn, some deoxit or, more cheaply and just as effectively, silicone lubricant spray left to soak and penetrate the threads should loosen it up enough to turn. Decades of heat will have allowed the threads to deform the plastic tube that ferrite core is in to where it might be kinda seized up. A little non-conductive lube will help loosen it up.

Edit: Heh, I just realized that I had to print a long version of a 2.5mm one of these to adjust a coil on a Radius Pivot a while back. Print this at a decent quality and it should work just fine for you.

 

[geerlingguy]

Not saying buy these, just providing an example: wrenches. Those are pretty expensive for a set of adjustment tools and I'm sure someone has made a printable set by now.

[...]

Edit: Heh, I just realized that I had to print a long version of a 2.5mm one of these to adjust a coil on a Radius Pivot a while back. Print this at a decent quality and it should work just fine for you.

Thanks! I just looked on Printables, and someone made the perfect little print for this: TV set / CRT alignment tool (tweaker)

Even better, someone in the Makes has a picture of it being used on the SE (and someone else said they used it on the Classic), so seems like the perfect tool for the job.

I'll try to remember to share a picture tomorrow if I can get around to tweaking the image!