My Nikon F4 is a late model, very good condition unit, and thus, I don't think I should toss and replace it. Rather, I want to just have it serviced.
The problem is that there appears to be some sort of contact issue between the DP-20 prism and the body. When a flash is on the camera, sometimes it doesn't fire, and sometimes it does. If the flash is leaning forward, then it doesn't fire. If its leaning back, it does.
I've solved the problem by putting a small, folded piece of paper between the prism and the body at the front of the prism. So I am 99% sure it is not a hot shoe/flash connection issue. I've also pushed the flash forward (gently) and pushed or pulled on the prism and as long as I push the rear of the prism down, the flash will fire.
I've also tried cleaning the contact area, but this doesn't help.
I'm wondering where I can send my F4 off to to have it looked at. Anyone have a recommendation?
May I recommend that you try another DP-20 first? Even though it seems to be in the body, it may still be a prism issue. Getting another DP-20 will be about 1/2 the cost of having your F4 opened up and worked on. Even through KEH with the DP-20 being an EX grade prism.
F5, F FTn - John Laughlin Photography - nature photographer
Interesting that you posted this now. My F4s has exactly this problem and I came here to search about it. I thought maybe it was the finder too so I bought one to replace it but the new one does the same thing. It seems that it's loose in the rails and the finder moves more than it used to, keeping the contacts from connecting properly.
In your case, pop the finder off. Take a #0 phillips screwdriver, and loosen the screws holding the rail on the right side of the finder well (side with the shutter speed dial). Slide the rail toward the middle of the finder well. Tighten the screws. Try remounting the finder. If you got it too tight, loosen the screws and adjust the position of the rail again, this time, moving back toward the shutter speed dial. Once you get it to the point that it slides in smoothly and doesn't wobble back and forth, mount your flash, and see if it fires.
F2AS, F FTn - John Laughlin Photography - nature photographer
I tried that and then the rail started getting loose again so I took the rail completely off and I was able to make myself a "wedge" to go between the rail and where the side contacts the body (using a small bit of cardstock cut from the end of an old business card).
Once inserted and screwed back together the finder now fits very snugly and the contacts meet up as they should.
I'll probably find myself a small bit of light seal foam and cut it to size to replace the card eventually, but for now it works.
Thanks so much for the suggestion about the rails, you got me started on the right path. Such a simple solution I was missing it.
In Shutter Priority mode, I set a shutter speed to anything slower than 1 second and it is pretty obvious that the camera is giving me a much longer exposure. Several seconds longer than whats on the dial and displayed in the viewfinder. When the exposure ends (mirror dropping down) the camera essentially freezes and the little red ligh flashes. If I cycle the power button the camera will shoot again but I must do that.
However, in Aperature priority mode, the camera's shutter speed seems to be correct. Same with P and Ph however sometimes the freeze up problem pops up.