So, I've got this old Beogram 4004..

It needs a new drive belt, but before I do that, I want to make sure I can get the tone arm working right.  Occasionally, it fails to drop the arm, and the arm always lifts slowly instead of snapping up.

If I take the right spring out, the solenoid always kicks out correctly, but when I put it back in, sometimes it just twitches instead of locking in the extended position.  If it does kick out all the way, it locks correctly, but if it just twitches, pulling it all the way out doesn't lock it.

I get about 1.4 volts across the terminals of the solenoid, which seems kinda low to me.

I took the left spring out and removed the linkage under it.  With those removed, the arm connected to the dampener seems to work fine.  It has resistance in the direction that drops the arm and moves freely in the direction that lifts it.  The arm connected to the solenoid and the right spring are still pretty stiff though.  I don't know if it is the solenoid slowing it down or the pivot point.  I'm not sure how much more disassembly would be required to disengage the solenoid from this lever, and the C-clip on the pivot is really stiff and doesn't want to come off (or even turn).

Any tips? 

Welcome to Beoworld !

What you have are typical symptoms of need for lubrication.
We've had this countless ttimes so I'm sure you'll be able to find more info if you do a search.
Anyway, these are the points that stops most Beograms of this series for lowering correctly.
Take the things apart, clean it well using isopropanol (tapehead cleaner) and add a small amount of acid-free oil (sewing-machine oil);

Martin

Any tips on getting that C-clip off the lower arm pivot?  Mine is so tight it won't even turn, much less spread open.

I'm in my office now, so I can't get a good look, but am I right in assuming the upper arm will lift off in one piece with the dampener if I remove the two screws at the base?

I use teflon oil (really just a light synthetic with a tiny bit of teflon added) for most of my oiling needs, would that work, or should I brave the sewing shops and get some proper sewing machine oil?

There's a tool designed for handling the clips.
It will be hard to remove it and reinstall it using anything but the right tool.

Something like this:
http://www.blinds.com.tw/images/making_Tools%5C%5C%5C%5C%5C%5Cmaking_Tools/C-Clip_Tool.jpg

I don't recall if there's a clip on the top pivot point originally and it was just not mounted at the time the photo were taken but the
things come apart fairly easily when the clips, springs and screws are off, even if you
may have to work the arms a bit to losen up the seized oil and free the arms.

Teflon oil will be fine, I'm sure.

Martin

I've used snap rings before, and I've even got a set of pliers for them, just none small enough.  I spent a while looking for a smaller set today, but even the smallest one I could find was still too big, so I just forced it off with a smallish set of pliers.  Naturally, this mangled the clip.

It seems to work just fine without it, but I'll probably run out to a hardware store and pick one up.  Or maybe I'll just leave it off for a while and see if that arm tries to wander up the pivot.

Cleaning and reoiling was very painless.  Thanks much for the help.

Now to wait for the replacement belt to arrive in the mail... 

Looks like I get to answer my own question.

That retainer on the top of the lower pivot is indeed needed.  Without it, the arm will work loose and the end will ride up over the other linkage.

Interestingly enough, that pivot doesn't have a groove to accept a clip, it just stays on by compression.  I ended up getting a pushnut bolt retainer for a #6 bolt.  This is basically a washer with sections of the inner edge bent upwards to form teeth.  It just pushes on and the teeth in the center have a bit of grip to keep it from lifting off.