Two Canon EFs not working: Damage to the power supply caused by battery electrolyte [repaired both]

[Andreas Thaler]

View attachment 381867

The new cable is installed, the epoxy is now hardening.

Trying to press one end of the cable onto the mating contact with pliers and then fixing the connection with epoxy only worked for a short time on both EFs. So I'm crossing this method off my list.

 

[Andreas Thaler]

Another fight with the battery compartment: attempt with copper foil

Since the power supply was no longer working, I checked the connection fixed with epoxy for continuity.

As expected, no current was flowing here.

Using the Dremel Stylo and my smallest milling head, I removed the epoxy.

Since I cannot solder on the contact, I attached two pieces of self-adhesive copper foil that conducts on both sides.

I linked both pieces with enameled copper wire that could be soldered onto the copper foil. This means the battery is connected again in the compartment.

The wire was actually not necessary, since the copper foil made a conductive connection with the contact. But since my multimeter showed no continuity between the two sides of the foil, I decided on this solution.

I later discovered that the foil does conduct on both sides, namely when it is soldered.

Learned something new again.

To stabilize the blue cable, I applied epoxy again.

The solution seemed stable and passed the continuity test with the multimeter.

The test after installing the battery holder showed that the voltage supply was not working.

The cause was a short circuit between the plus and minus of the battery induced by the surrounding contacts being pressed together.

In the EF's viewfinder, the measuring needle abruptly swung up and down when the shutter speed dial was turned.

When removing the battery holder, the blue cable came off.

So a more mechanically robust solution was needed.


All's well that ends well: Connecting the cable with eyelet, screw and nut

Following @Donald Qualls in

Post in thread 'Spare parts for photo equipment repairs: three options and a fourth'
https://www.photrio.com/forum/threa...hree-options-and-a-fourth.209949/post-2841295

I started looking for a suitable eyelet, screw and nut in my spare parts supply.

There are two holes in the battery contact that are actually intended for stabilization in the battery holder. I wanted to use the hole with the protruding connection to attach the cable.

New screws and nuts are available in abundance.

As if I had asked for it, a suitable cable with an eyelet was also findable.

The installation on the contact worked.

To avoid another short circuit, I added a piece of shrink tubing for insulation.

A new attempt …

… the battery compartment is mounted, all three cables are soldered onto the circuit board.

And now the power supply is working as the battery test LED indicates.

 

[Andreas Thaler]

From the outside, only a piece of the shrink tubing is visible in the right battery compartment and the spot is slightly higher than before.

This should last another 50 years!

With less at the table it probably won’t work


+++

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

 

[koraks]

Brilliant!

 

[Andreas Thaler]

Brilliant!

Thanks!

 

[Andreas Thaler]

Detailed information about the Canon EF:

Canon EF (1973)

What is it? This is a Canon EF 35mm single lens reflex camera made by Canon Inc of Japan between the years of 1973 and 1978. It used Canon's FD lens mount

mikeeckman.com

 

[Chan Tran]

The electrical connection, fixed with epoxy, obviously didn't hold, so I'll continue. Thankfully it's only one connection on the battery holder that I need to fix.

More on that soon.

I have a non working EF with good battery holder. How do I send it to you?

 

[vandergus]

Amazon.com

 

[Andreas Thaler]

I have a non working EF with good battery holder. How do I send it to you?

Very nice, thank you!

I have a third EF for that I could use, but that's for spare parts.

I would offer the battery holder on eBay, for example, it would certainly be a sought-after replacement.

 

[Andreas Thaler]

Amazon.com

Thanks will try to get.

 

[Chan Tran]

I can't post to the classified section but I have 3 cameras,
Nikon FM
Canon EF
Minolta XE-7
All bad. I want to give them away for someone willing to pay the shipping cost.

{Moderator's Note - post copied to its own thread in the "Free" section of the Classifieds}

 

[Andreas Thaler]

Another fight with the battery compartment: attempt with copper foil

View attachment 382816

Since the power supply was no longer working, I checked the connection fixed with epoxy for continuity.

As expected, no current was flowing here.


View attachment 382810

Using the Dremel Stylo and my smallest milling head, I removed the epoxy.


View attachment 382814

View attachment 382815

Since I cannot solder on the contact, I attached two pieces of self-adhesive copper foil that conducts on both sides.

I linked both pieces with enameled copper wire that could be soldered onto the copper foil. This means the battery is connected again in the compartment.

The wire was actually not necessary, since the copper foil made a conductive connection with the contact. But since my multimeter showed no continuity between the two sides of the foil, I decided on this solution.

I later discovered that the foil does conduct on both sides, namely when it is soldered.

Learned something new again.


View attachment 382821

View attachment 382813

To stabilize the blue cable, I applied epoxy again.

The solution seemed stable and passed the continuity test with the multimeter.


View attachment 382820

The test after installing the battery holder showed that the voltage supply was not working.

The cause was a short circuit between the plus and minus of the battery induced by the surrounding contacts being pressed together.

In the EF's viewfinder, the measuring needle abruptly swung up and down when the shutter speed dial was turned.

When removing the battery holder, the blue cable came off.

So a more mechanically robust solution was needed.


All's well that ends well: Connecting the cable with eyelet, screw and nut

Following @Donald Qualls in

Post in thread 'Spare parts for photo equipment repairs: three options and a fourth'
https://www.photrio.com/forum/threa...hree-options-and-a-fourth.209949/post-2841295

I started looking for a suitable eyelet, screw and nut in my spare parts supply.

There are two holes in the battery contact that are actually intended for stabilization in the battery holder. I wanted to use the hole with the protruding connection to attach the cable.


View attachment 382817

New screws and nuts are available in abundance.


View attachment 382812

View attachment 382822

As if I had asked for it, a suitable cable with an eyelet was also findable.

The installation on the contact worked.


View attachment 382809

To avoid another short circuit, I added a piece of shrink tubing for insulation.


View attachment 382819

View attachment 382811

A new attempt …


View attachment 382823

… the battery compartment is mounted, all three cables are soldered onto the circuit board.


View attachment 382818

And now the power supply is working as the battery test LED indicates.

The connection of the cable to the battery contact via eyelet, screw and nut holds. The light meter and battery control work.

This completes the double project.

For similar cases, I recommend looking for an original battery compartment for replacement, with all three cables still soldered on.

 

[Laurent]

@Andreas Thaler I think I need to thank you

Your post inspired me to get the EF I bought for parts some time ago, investigate a bit, which made me able to fix the battery test circuit.

By some careful cleaning/oiling, I even got the shutter to "work" (one speed for all settings, with or without battery).

So when a EF + 50/1.4 combo was offered for sale I pulled the trigger, hoping to make one working camera with the two, and corssing my fingers for the lens to be in a fixable state.

I've got it today, and this has been my first full success: the "new" camera was missing the "on/off" lever, which made it inoperative (if the ball bearing is missing, it does not even stay on when one uses a spanner to turn it on). So I removed the lever from the other one, put two batteries and voila... works like a charm.

And the lens is not so bad, even if focus is a bit stiff and the original hood does not lock in position (but I guess I'll find a way)

So I'm a very happy "repairer" today!

(yes, she needs some cleanup, I've just dusted the most I could with compressed air)

 

[Andreas Thaler]

Great!

 

[Dennis S]

Very informative post as I have 3x EFs and only one of them works properly. They were purchased many years ago when digital was just starting and people were letting film cameras go for a song and a dance. None of them worked until I got home and replaced the batteries with 1.4v hearing aid batteries. One came back without any problems and with your detailed instructions I may attempt the other 2 as I have been looking for battery repair on these as finding information on this was virtually impossible. Your references to other sites like NatCam was extremely helpful to me.

 

[Andreas Thaler]

Very informative post as I have 3x EFs and only one of them works properly. They were purchased many years ago when digital was just starting and people were letting film cameras go for a song and a dance. None of them worked until I got home and replaced the batteries with 1.4v hearing aid batteries. One came back without any problems and with your detailed instructions I may attempt the other 2 as I have been looking for battery repair on these as finding information on this was virtually impossible. Your references to other sites like NatCam was extremely helpful to me.

I am very pleased

Good luck!

It's worth investing work into this beautiful camera!

In addition to a new shutter and auto exposure, the EF was loaded with many other useful features. It was positioned below the F-1, but above the FTb in Canon’s lineup. See the image to the left of a Sears catalog from 1976, which lists the F-1 with 50mm f/1.4 lens for $549.00. The EF and FTb with the same lens are listed at $459.00 and $299.00 respectively. When adjusted for inflation, those prices are $2350, $1965, and $1280 today. Like the F-1, the EF is only available in black, which was the preferred color for professional photographers. The lack of a silver model and the EF’s high price, confirms it was targeted primarily at the advanced amateur or professional photographer.

Canon EF (1973)

What is it? This is a Canon EF 35mm single lens reflex camera made by Canon Inc of Japan between the years of 1973 and 1978. It used Canon's FD lens mount

mikeeckman.com

 

[tokam]

I bought my EF from a Canadian member on this forum about 10 - 12 years ago. I sent it off to my favourite tech who was trained by Canon in earlier days. He approved this mod to the battery chamber which consists of a spring wound inside the battery chamber to provide both electrical contact with the battery and to firmly locate the smaller silver oxide, 1.5V battery. It currently has an Everready 357 sized battery and is performing perfectly.

 

[Andreas Thaler]

I bought my EF from a Canadian member on this forum about 10 - 12 years ago. I sent it off to my favourite tech who was trained by Canon in earlier days. He approved this mod to the battery chamber which consists of a spring wound inside the battery chamber to provide both electrical contact with the battery and to firmly locate the smaller silver oxide, 1.5V battery. It currently has an Everready 357 sized battery and is performing perfectly.

Also visually an attractive solution

 

[Dennis S]

Well thanks to your photographs and NatCam repair PDF I have another EF SLR meter working correctly. The blue wire was giving me problems and resoldering it gave the right connection. The other camera had a dent in the bottom near the batteries and I found the capacitor C2 was smashed and needs replacing. Not a professional repair but I can follow photographs and not too sure that replacing the C2 is possible. I may go into the camera again and see about the battery test switch as the light does not come on in a test. If I have 2 out of 3 EF's working seems like a good place to be with older cameras.

 

[Andreas Thaler]

Well thanks to your photographs and NatCam repair PDF I have another EF SLR meter working correctly. The blue wire was giving me problems and resoldering it gave the right connection. The other camera had a dent in the bottom near the batteries and I found the capacitor C2 was smashed and needs replacing. Not a professional repair but I can follow photographs and not too sure that replacing the C2 is possible. I may go into the camera again and see about the battery test switch as the light does not come on in a test. If I have 2 out of 3 EF's working seems like a good place to be with older cameras.

Great!

 

[Andreas Thaler]

I opened my spare parts EF today when I removed the winding lever for a colleague.

Here are a few impressions from the top deck:

 

[Andreas Thaler]

The winding lever can be removed after unscrewing the retaining ring to the left (as seen from the back of the camera).

The paint on the camera is very sensitive to scratches, and slipping with the tool will result in immediate punishment

Most of it is made of solid metal.

Attention, there are also two ball bearings in this area.