DIY repairs: Limits of what is possible?

[Andreas Thaler]

With DIY repairs, you can fix many of the common problems with cameras, e.g. disintegrating light seals, contact problems in the battery compartment, defective capacitors, etc.

With good instructions or self-study, you can also complete more complex repair tasks, such as removing the mirror box to fix mechanical problems there or replacing broken broken gears in a motor drive.

Removing the front panel on this Nikon F4 was easy with good instructions. But is the flange focal distance correct after assembly?


However, this takes you into an area that may change the original factory adjustments.

If the mirror box is no longer positioned exactly as it was set at the factory after installation, the flange focal distance, i.e. the distance to the film plane, is no longer correct. This results in blurred images.


Know-how and measuring devices

Misalignments can also be caused by force being applied to a camera, e.g. by a fall. The optical system then has to be measured and re-adjusted. This requires know-how and measuring devices.

The autocollimator for determining the focus point on the film plane is an example of this.

A shutter speed and an exposure tester are also required to adjust a camera if, for example, parts have been replaced or the settings are no longer correct.

It is clear how the circuit board can be unscrewed on this Nikon F3. But how do I correctly adjust the potentiometers arranged one above the other on the right, for example to adjust the exposure metering system?


Measuring devices that are not easy to understand and are only useful if you can also make adjustments to the camera itself. In other words, you know how to correct the flange focal distance and make electronic adjustments to the circuit, which can vary from camera to camera.

A professional repair shop should be equipped for this kind of work.


How far can you go?

I wonder how far you can go as a DIY enthusiast in this area, what you can still do yourself and whether you need expensive equipment for this or whether you can build this equipment yourself.

What are your experiences with this topic? How far do you go with DIY repairs?

 

[vandergus]

There are definitely some areas of camera repair that are not reachable by your typical home hobbyist. Mostly things that require proprietary units from the OEM to make adjustments. Like calibrating autofocus sensors or changing the timing on some electronic shutters.

But flange focal distance is pretty doable. I use a basic dial depth gage with a couple gauge blocks to calibrate it and to act as the "surface plate" in the film plane. Removing and replacing the mirror box or front plate usually doesn't affect the flange distance but it is good practice to check it during reassembly. If there are any changes or if it is out of spec, adjustments aren't too bad either. Some cameras have adjustment features incorporated into the camera (like the Pentax K1000), but many just use shim washers.

More importantly, I think we should be careful not to limit our imagination. Some things may seem impossible to you or I because it is far outside of our experience. But all it takes is one dedicated individual to develop a new tool and it can change the game. For example, there are folks in the retro computing space that have reverse engineered old chips so replacement parts could be made. And this guy completely reverse engineered the entire hardware design of the Pentax Electro Spotmatic. Insane.

 

[Nicholas Lindan]

There are definitely some areas of camera repair that are not reachable ... Like calibrating autofocus sensors...

That was my limit on a Nikon 35ti. I would need the unobtainable Nikon calibration software.

I keep thinking there should be another way; smooshing the sensor/transmitter on the circuit board; introducing a bit of glass to shift the AF image; changing the rest position of the lens; altering the lens motor's position sensor.

Oh well, I have more cameras than I can use. What do I need one more for?

 

[OAPOli]

For checking flange-focus one can also use a granite check stand with a dial gauge. You stand the camera on the film rails (piece of glass + precision block). You would likely need a reference block as tall as the flange focus distance to set the zero point. I don't have one (yet?) but they are not too expensive.

I've been using a live-view digital camera with a long lens precisely focused at infinity as an autocollimator. You press a piece of glass with a sharpy mark on the film rails and inspect it through the camera and collimator lenses.

One thing that I would like to measure is the mirror angle. Not sure how DIY that...

 

[Sirius Glass]

I will replace light seals for Hasselblad film holders, but these days that is about it.

 

[ic-racer]

Nice that the camera he is using has the common buss. I do like the way he used the little dip switches. When contemplating something similar, I was going to use a separate camera body for the 10 or so switches needed to test anything on the circuit.

The camera in the picture was repaired with a NOS circuit board.

 

[Andreas Thaler]

Nice that the camera he is using has the common buss. I do like the way he used the little dip switches. When contemplating something similar, I was going to use a separate camera body for the 10 or so switches needed to test anything on the circuit.

The camera in the picture was repaired with a NOS circuit board.
View attachment 369944

 

[Andreas Thaler]

For checking flange-focus one can also use a granite check stand with a dial gauge. You stand the camera on the film rails (piece of glass + precision block). You would likely need a reference block as tall as the flange focus distance to set the zero point. I don't have one (yet?) but they are not too expensive.

View attachment 369928

I've been using a live-view digital camera with a long lens precisely focused at infinity as an autocollimator. You press a piece of glass with a sharpy mark on the film rails and inspect it through the camera and collimator lenses.

One thing that I would like to measure is the mirror angle. Not sure how DIY that...

Thanks for the interesting suggestions!

 

[Andreas Thaler]

I will replace light seals for Hasselblad film holders, but these days that is about it.

This is already highly specialized; not everyone can do it.