F4 electrical question

My F4 has an issue I'd like to sort out. When zooming the lens, the flash (SB-24 and 28 have been tried) doesn't zoom to follow. Both flash units zoom properly on my F5 and N90S so I know they work fine. I'm guessing the problem is in the DP-20 viewfinder but I'd like to confirm this before I go and spend the $60.00 plus for a replacement. What I need is some insight on the electrical connection between the finder and the camera body. What pin(s) control the flash zoom and what should I see on those pins with either a volt meter or oscilloscope? Can anyone help?

Thanks much,

Ed

Remove the finder. Check the contacts on both the finder and body for the same height and same degree of brightness. Check pins for smoothness of operation. Clean contacts if they are not bright and shinny. Sometimes reseating the finder clears the problem.

When you remove the finder, flip it over and hold it so the contacts are towards you, and the glass is away from you. From right to left, the 5th contact is the TTL contact. Make sure it is in good condition. It may have recessed to far in, or it may have broken off. If it's recessed in, you might be able to pry it back up (gently) so that it makes contact. If it is broken off, take a very small piece of tin foil / aluminum foil, ball it up, and stick it in there. It will work, and if you're careful, you won't loose it when removing/installing the finder.

I had to use the tin foil on mine for a different contact, and it worked like a charm.

You ever had one of those weeks? I'm in the middle of one now. Just wanted to say thanks for the tips! Like I said, its been one of those weeks, and I haven't had a chance to pull out the F4, but hopefully maybe if I'm lucky I'll be able to get with it over the weekend. So thanks again and I'll let you know how it goes.

Ed