There's always a chance: Troubleshooting electronic faults in electromechanical SLRs and accessoires

[Andreas Thaler]

SLRs such as the Canon T90, Minolta (Maxxum/Alpha) 9000 AF, or Nikon F3 with their flexible circuit boards that run through the camera body in several layers. Peppered with ICs and tiny electronic components.

How can faults in electronics be found and repaired?

As always

professional guidance is the key to repairs in this camera class.

Troubleshooting guides in technical documentation help to find electronic faults.

Often these are simple contact problems, but electronic components can also fail. Cleaning or replacement can help here. The main work is then not the actual repair, but disassembling and reassembling the SLRs.

To encourage you (and me)

I have compiled a few examples from my work here.

Even if there is never a guarantee of success, there is always a chance

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Inspection and replacement of electrolytic capacitors in a Minolta Auto Winder G. These electronic components can leak after decades of service, causing liquid electrolyte to escape and ultimately leading to complete failure of the capacitor. The problem could be found by visual inspection.

A dual diode in a Canon T90 proved to be defective. The C & C Troubleshooting Guide for the T90 led me to the fault. I was able to unsolder the diode, check it, and replace it from my spare parts stock.

The DC/DC converter in a Canon T90 was overloaded. The resulting heat destroyed components on the circuit board. A visual inspection revealed the fault. Replacement of the entire circuit board.

In a Canon T90, the copper winding in a release solenoid was broken. This meant that no more current could flow and the solenoid failed. Found by visual inspection. Replacement of the component.

Here, I damaged the circuit board of a Canon T90. This severed the conductor tracks, but luckily it was a T90 for spare parts that I didn't need to fix. The circuit board would then need to be repaired and the conductor tracks bridged with wire. A tricky job with a soldering iron.

The main display on a Canon T90 was showing nonsense. On the off chance, I replaced it along with the built-in electronics, and the problem was solved.

 

[Andreas Thaler]

The viewfinder LCD on a Nikon F3/T gradually failed, digits were no longer displayed, the cause was corrosion of the contacts. Replacement solved the problem.

This IC in a Canon T90 can also be replaced. To do this, it is desoldered and soldered using hot air. This is not easy, as the IC must not be overheated and the surrounding parts must not be damaged. I was just practicing here. A function check will later show whether the operation was successful.

Replacement of all electronics in a Nikon F3AF. This fixed a fault that I was unable to locate precisely.

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A word of caution

Please keep in mind that you’ll be using highly flammable solvents for service work, and their fumes are harmful to your health. Soldering also produces fumes that should not be inhaled. Dangerous high voltages can be present when handling electronics, especially in conjunction with electronic flash units and mains. Therefore, familiarize yourself with the safety regulations beforehand and ensure your safety. Depending on the activity, protective gear may be advisable.

All information provided without guarantee and use at your own risk.

Acknowledgments

Without the work of Master Larry Lyells, in particular, we wouldn’t have the detailed technical information we need today for service/repair of SLRs.

The SPT Journal and The Camera Craftsman, which he helped shape significantly as an author, and which contain all the necessary information and instructions are available for a fee through Learn Camera Repair.

We owe our access to them to Eugene Pate, the founder of Learn Camera Repair.

 

[lumoStoria]

Nice work. What's your experience with sourcing electronic spare parts? Except from general-purpose components (like capacitors and transistors), is there any chance to find individual NOS spare parts or is it always necessary to have a couple of donor cameras in stock?

Whenever I cannibalize one camera to fix another one, my heart bleeds. I always think that even the donor camera was not beyond repair and would have also had a right to be saved .

 

[Andreas Thaler]

Nice work. What's your experience with sourcing electronic spare parts? Except from general-purpose components (like capacitors and transistors), is there any chance to find individual NOS spare parts or is it always necessary to have a couple of donor cameras in stock?

Thanks!

New replacement parts (e.g., from closed-down repair shops) pop up on eBay every now and then. They’re expensive.

See

Collection of spare parts for Nikon F3 and F3/T including a F3 Pin Registration (not for sale)

I managed this year - more or less by chance - to get a collection of spare parts for the F3 and F3/T including some F3 bodies, one of which is very rare. The spare parts are originally packaged, unused from workshop storage, including two complete electronic boards in the box. A remarkable...

www.photrio.com

That leaves defective cameras for sourcing spare parts, but even those are becoming increasingly rare and prices are rising. So I grab whatever I can find and am glad that I’ve stocked up enough to last me the rest of my life. However, I work only for myself and my reports, not commercially.

Whenever I cannibalize one camera to fix another one, my heart bleeds. I always think that even the donor camera was not beyond repair and would have also had a right to be saved .

Yes, tough decisions often have to be made here