I recently acquired a Meade Research Grade mount, from the 1980s, I believe. It has an issue, and I posted about it on the Classics forum, but got no suggestions, so I'm trying here.
The mount itself functions fine. It's meant to use 115vac wall current, and you can simply plug it in to get RA tracking. That works. But it also came with a control box and hand controller. When working properly, this controller provides motor control in both RA and via a small motor on a tangent arm for Dec adjustment. This is really helpful, since the huge mount does not have manual slow motion controls.
Unfortunately, the controller is not working properly. The Dec control works fine, but RA does not work at all with the control box. Since RA does track when plugged directly into the wall, this means that the issue must be with the controller box and hand controller. My son, who is pretty knowledgeable about electronics, and he opened the box and hand controller up. Because we don't have a schematic of the guts of these things, and because they are more complex than we anticipated, we are unable to even test them accurately, let alone fix them.
My son did find two things: First, he found that there is voltage going to the RA connection, and it's 50vac. We don't know if that's proper or not. Second, inside the controller, he found a loose wire. The thing is, the wire is quite short, and we cannot find a place that it will reach that seems like it is where the loose end should attach.
So, I'm hoping someone that has one of these controllers, or has had one in the past, might be able to help us. It would be great if someone could open up their working hand controller and compare it to the photo below, and then let us know where the wire attaches. Or maybe someone has the schematic. Or maybe it's a known problem with these that has nothing to do with the loose wire. We'd like to get the mount up and running, after a tune-up and retouching of the paint, so that we can sell it -- along with an 8-inch f/8 reflector -- in order to raise funds to support our public observatory. We have more scopes than we can use already, and would like other things, like an h-alpha solar attachment for one of our refractors.
Here's the mount (you can just see the reflector behind it, which has a cell and mirror made by Edmunds):