Nikkormat FTn, lightmerer turns off from f8 to f11

[zanxion72]

I have a Nikkormat FTn with a lightmerer that turns off from f8 to f11. It goes smoothly all the way from f2 to f5.6, then turns of from f8 to f11 and then back on from f16 to f22. Is that repairable? I can estimate the correct aperture between these, but I would like to have it fully operable.

 

[George Mann]

It sounds like your ring resistor is either damaged, or extremely corroded.

 

[RLangham]

I have a Nikkormat FTn with a lightmerer that turns off from f8 to f11. It goes smoothly all the way from f2 to f5.6, then turns of from f8 to f11 and then back on from f16 to f22. Is that repairable? I can estimate the correct aperture between these, but I would like to have it fully operable.

You may have dirt or rust on the ring sensor. Something is obstructing contact in that short section of the arc. It's probably fixable if you send it to a qualified shop. There's certainly some shops in Europe but I don't know any personally as an American.

There are any number of problems with old Nikon ring resistor circuits--they're the first thing to go out on TTL Nikon F finders too.

 

[zanxion72]

I removed the lens mount and cleaned the ring of the aperture that set the resistance for the meter. there was something like foam stuck to it, perhaps from the mirror bumper that was not there when I bought it. Now it runs nice and smoothly.

 

[RLangham]

I removed the lens mount and cleaned the ring of the aperture that set the resistance for the meter. there was something like foam stuck to it, perhaps from the mirror bumper that was not there when I bought it. Now it runs nice and smoothly.

You're braver than me then. I stopped opening up cameras I care about long ago. I'm glad it worked out.

 

[abruzzi]

The FTn is actually pretty easy to work on parts like that, though I don't think I'd try to disassemble the copal shutter. I had one where the ring the indexing pin was on didn't snap back, which caused some issues indexing the lens. Getting to that and fixing was pretty easy. The other thing I noticed was on my FTn's when I removed the top plate, the wire that needed an inline diode for voltage regulation (to deal with the lack of mercury batteries) already had a secion stripped with a clear bit of sheathing over it. A quick snip, remove the clear sheath, slide on some shrink wrap, solder the diode, and shrink the heat shrink. I think it was a 15 minute job, and I'm not very good at these things. I wonder is Nikon know the mercury batteries were going out when they made the FTn? It seemed really designed to quickly adapt to a different voltage.

 

[CMoore]

It sounds like your ring resistor is either damaged, or extremely corroded.

My photo teacher had a Nikon F2 that was doing the same thing.
She sent it to Sover Wong (this was 6 or 7 years ago) and that was, indeed, the problem.