Guide for Dismantling a Nikon F-301 Camera

Nikon F-301
This camera marked a new phase in the design of the Nikon SLR. For one thing it includes it’s own auto-winder, which is capable of clocking up a respectable 2.5fps. Another departure from the ‘classic’ Nikon in the use of plastic for some of the body parts.

The use of plastic caused many to claim that this camera represented the beginning of the end for the Nikon as the ‘camera of choice’ for many professionals. In service however these cameras have proved as reliable and robust as it’s all metal predecessors. This may be due to the fact that most of the body is still metal, but that it is designed with the same attention to the requirements of the professional for a tough workhorse. This may sound like an odd thing to say about a camera with a fixed focusing screen, and without such features as a mirror lock or depth-of-field preview, but this should not detract from this 1985 offering from one of the worlds most famous marque’s.

This particular example was bought from a car-boot sale for next to nothing, with no lens. The mirror had jumped it’s mountings, (a common camera repair for these models.) probably as a result of dropping the camera onto a hard surface (possibly concrete) from five or six feet.

Most cameras would stop working in this scenario, many would not be repairable afterwards. This camera just requires the mirror re-mounting on it’s pivot!

The body shows some signs of the impact, which seems to have been directly on one corner, and there are a number of marks indicating heavy use. A perfect candidate for an exploratory operation. If I completely mess it up, I have lost little, and learned a lot!

Tools Required

There are no special tools required to disassemble this camera. That may have something to do with the Nikon design philosophy on serviceability. There are some obvious features that illustrate this to be encountered during the work here.

Starting Disassembly

As always, before starting to disassemble the camera, make sure that you have a notebook and pencil handy. The camera you have may have some differences to the one here, particularly with respect to wire colouring.

Begin by removing the film door. In common with many cameras this unclips by means of a spring-loaded hinge-pin.

 

The next item to go is the film rewind crank. Remove this the usual way.

 

The film speed dial is held in by means of a ‘C’ clip as shown here. It looks a little odd, but comes out easily using a couple of small flat-bladed screwdrivers.

 

Once removed you can see the film speed selector contacts. These can’t be removed yet, but you should be able to see if there’s a problem with the contacts here.

 

Now we have to get to one of the cover screws hidden beneath the soft rubber covering.
This is one place where we can see evidence of the thought given to servicing the camera. There is a convenient tag on the side of the body which makes peeling the covering off easy, without risking scratching the paint!

 

Just grab hold of the tag,

 

and start peeling.

 

Continue peeling unit lit’s off.

 

The screw revealed just needs to be loosened a bit.

If you intend to completely disassemble the camera you will need to peel the other side off too.

 

Now simply remove all the other screws holding the cover on as shown. Take note of which screw goes where, they look very similar but are not identical.

 

Once the screws are removed the top cover can be eased off.

The viewfinder bezel should be held in place while lifting the cover, and removed once the cover is lifted.

It’s a good idea to disconnect the wires to the hot-shoe now. Accidentally pulling a couple of wires off leaves you with a rather scary guessing game, especially when you consider some flashguns have trigger voltages of hundreds of volts. Guessing wrong could connect that to the voltage sensitive logic circuits in the camera!

At the very least you could wast a lot of time in trial-and-error wiring. (Two wires and two solder tags gives two ways of connecting them, three wires have six combinations. You can work the rest yourself!)

 

These four wires connect to the LED and the sounder.

 

You may find it easier to remove some of the wires at the flexiboard.

 

With that out of the way, you can now remove the bottom cover, and battery compartment. Just remove the five screws.

Four here.

 

One here.

 

Unsolder the battery wires.

 

Take a moment to examine the arrangement of levers visible underneath (above?) the battery cover. When reassembling the cover you will need to place these in the same relationship as they are now. (Assuming that the fault is not due to a problem here. That is not likely to be the case unless someone has been messing about in here!)

 

Now we want to remove the wires connecting the shutter to the electronics. As you can see there are quite a few wires to choose from.

The wires indicated below all connect to the shutter. The two connecting to the hot-shoe are the sync’ wires and should already be disconnected.

Four of the six remaining wires connect to the shutter solenoids, the remaining two connect to contacts on the closing curtain mechanism.

 

 

Now disconnect the DX contact wires. Make sure you take a careful note of their locations, as getting this wrong won’t stop the camera working, but DX coded films won’t be exposed correctly. There are a lot more ways of getting it wrong than right.

 

Once the body is separated you can see the DX contact connections.

 

Now disconnect the wires for the battery and the winder motor. Immediately beneath these is a flexi-strip connecting to the control PCB. Unsolder this quickly and carefully. Too much heat will cause the copper tracks to become unstuck from the strip. If you have a databack, this won’t work if this strip is damaged.

 

Now you need to release the film selector dial.

 

Remove the three screws here.

 

Now remove the body screws. Note the screw arrowed is different from the rest.

The screws on the other side.
Note the trimmers accessible here. Another well thought out feature. I don’t know exactly what they all do, but at least I can access them with the camera in one piece!

 

There are screws on the sides of this camera as well.

Once the screws are removed, ease the front of the camera up, and forwards a little. Lift the control PCB up at the rear, and push the sprocket drive shaft gear downwards to free the control PCB. Provided you have unsoldered all the wires, once the shaft is free the front of the body should lift away easily.

The Shutter

The copal shutter is a lesson in pure simplicity. There is the absolute minimum of parts required to perform the task.

I’ve removed it from the body here to show you in better detail, but unless it’s been physically damaged it is very unlikely to need attention.

 

This is normally under a dust cover, but I’ve removed that so you can see the simplicity of the design. There are just two solenoidswhich hold each shutter in the charged position, against their springs. Turn off the current, and they release them. There are no mechanical latches to wear-out or jar out of alignment.

 

In addition there are two sets of gold-plated contacts like this. One set closes when the opening shutter is just open. (Flash sync.) The other set close when the closing curtain has closed. So the camera knows it can return the mirror.
There is not the usual mechanical linkage from mirror, to shutter, and back to the mirror as there is in other designs, which is often the source of a lot of failures. The electronics control the sequence, something that electronics is very good at!

Mirror Lifting and Shutter Charging

 

The crank arm here simply lifts a lobe on the opening shutter mechanism, which in turn pushes the closing shutter both into the charged position. A lever driven by a cam on the winder mechanism presses on point 2, and point 1 actually presses onto the shutter lobe.
During picture taking another arm presses on 3, driving charging the mirror spring, and tripping the mirror release at the end of it’s travel.

 

This lever couples to a braking mechanism, and also trips a switch which causes the activation of the solenoids. Another solenoid holds the braking mechanism and switch engaged during the mirror lifting period. As soon as the mirror is in it’s upper position, the shutter is electronically fired.

Putting it all back together

 

When putting it all back check that the cam and lever shown here are in the position shown. Note the lever arrowed can cause problems. Make sure that it moves freely when the screws holding the PCB are fully driven home, while at the same time it is not flopping about all over the place.

 

The lever shown here at the bottom of the camera should be in this position.

 

Also release the gear here in the position shown. You will have to release the locking dog (Arrowed)to do this.

 

To keep the flexistrip out of harms way when putting the front and back together, hook the motor wires around it as shown.
The rest of the reassembly should be fairly plain sailing. Though it’s worth remembering that if you decide to test anything before assembly is complete, and the film door is closed the camera will not fire the shutter, and will attempt to load film on every press of the release button.

 

Conclusion

That just about does it for this one. You have seen how to dismantle one of these Nikon cameras, and noted one or two features of the Nikon design philosophy contributing to the popularity of these cameras among professional photographers, and serious amateurs. Admittedly, the approach does not result in the most compact and lightweight design, but they do result in a tough reliable design which is relatively simple to maintain in that state, which is after all what is called for.

Just in case you were wondering. After putting the mirror back onto it’s pin, it all works perfectly.