Nikon F4S shutter, mirror, aperture

hartacus

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Nov 15, 2016
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Hi all,

I've recently been given a Nikon F4S. It used to belong to a family friend who was a professional photographer. It's been used a lot, judging by the cosmetics, and possibly dropped as there's some damage to the viewfinder (the illumination panel is pushed in a bit). It's been in a shed until it came to me so the outside's a bit dirty. The inside's clean and dry though.

Fresh batteries. Electronics seem fine - it turns on, LCD/LED shows appropriate messages when different modes are selected (including focus confirmation, though I don't have an AF lens for it). All modes appear to work, including metering selection on the viewfinder. Film winds on correctly (well it does now - I think some of my cleaning cleared up some of the sensor contacts).

However, on pressing the shutter button fully, the shutter doesn't fire, the mirror doesn't flip up, and the aperture doesn't get stopped down. The film does get advanced one frame, but the status light flashes (indicating a sequence error, I believe). Doing this with the lens off, there's a slight wiggle of the stop-down armature, but that's the only movement.

So I have a few questions, since I'm pretty new to this camera:
1. Are combined shutter/mirror/aperture issues common for the F4?
2. To an experienced F4 user, does this seem mechanical or electronic? Or too hard to say? I'm kind of suspecting a misalignment of the mechanism, but most of my experience is with more mechanical cameras so idk
3. Is there a single point of failure among those three components, such that e.g. if the mirror isn't raised the shutter can't fire, or something?
4. Is it possible to read the EEPROM data without the fancy tool thing?

Thanks in advance!
 

shutterfinger

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Feb 25, 2013
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2. To an experienced F4 user, does this seem mechanical or electronic?
Yes.
There is a complete 196 page factory repair manual at http://arcticwolfs.net/ . Download it and start with the shutter switch as its likely not making proper contact then move on to the release solenoid(s).
I bought mine new in 1991 and added a multi control back in '92 but have not run more than 200 rolls of film through it.
The F4 starts with the basic body then adds a letter for the different battery packs. The F4 with a MB21 is F4S. Download the instruction manual for it here: https://drive.google.com/file/d/1Zccpg3z3UsI5H7mKxliicZOCblbAxMr4/view?usp=sharing
 

Theo Sulphate

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Just for completeness, try the auxiliary shutter button near the bottom of the MB-21 and see if the result is the same.
 

ronnies

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Aug 9, 2014
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Just for completeness, try the auxiliary shutter button near the bottom of the MB-21 and see if the result is the same.

And for more completeness try the cable release socket on the back of the base on the rewind side.

Ronnie
 
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hartacus

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Nov 15, 2016
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Sydney, Australia
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start with the shutter switch
Thanks, I'll check it's making contact properly. The rest of the sequence appears to happen normally, including film advance, so if it's not making contact properly it's only a partial thing. I've had a look through the service manuals (definitely an F4S) but was mostly following a post on here about disassembly to fix a sticky aperture issue, so I'll follow the manuals more closely.

Just for completeness, try the auxiliary shutter button near the bottom of the MB-21 and see if the result is the same.
And for more completeness try the cable release socket on the back of the base on the rewind side.
Tried both, and same result unfortunately, but thanks!
 

shutterfinger

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Sequence of operation begins on page 53 of the service manual. It sounds like the camera is in blank shooting or the shutter charge motor is not being activated or is bad.
Have you tried advance modes than other than S? Hold the lockout button down and move the mode switch from extreme to extreme rapidly 10 to 20 times with power off then power on and try each advance mode.
 
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