Repairing a Practica BC1

2026/05/07

At the beginning of the year I stumbled upon a film camera on a local auction website. The listing said it was functioning, with only its timer mechanism being stuck. At the time I thought to myself it would be an easy fix. Boy was I wrong.

(Exhibit one: I was wrong)

After I got my hands on it I quickly realised there was something wrong. Replacing the battery it became obvious there was something wrong with the electronics. No matter the setting the shutter speed seemed to either always be in bulb mode or on a random setting. Digging myself deeper into a hole I did some research and found out these cameras often had their electronics fail. I also discovered there was very little information about repairing these.

Taking the camera apart

Lets get into how to take one of these apart. I should warn you that you may damage or fully destroy your own camera if you try your luck with opening it up. I myself cracked the plastic shutter lock and scratched the body.

# Top part

(Sadly didnt have a better photo)

To remove the top part of the body we first need to remove the winding mechanism, the flash plate and the wind lever. After that we need to remove 5 screws and carefully remove it.

Starting with the winding mechanism first pull it up to pop open the film compartment. Leaving the compartment open pull it down and secure the fork which would normally hold the film. It should be enough to just hold it in place with your fingers, but if your camera is a bit rusty, like mine was, you can use a flathead screwdriver instead. Having it secured you can now unscrew the top plastic part you would use to wind up the film.

Having unscrewed the winding mechanism you should see a funny looking nut. You can try your luck unscrewing it with screwdrivers or buy a specialized tool. I unscrewed it using pliers (the surrounding plastic part can be pressed down, but be careful).

Removing the flash bracket is way easier. The screws holding it in place are covered by a metal plate. The plate is just snapped in place so all you need to do is prop up the middle front (front meaning closer to the lens) part of it and slide it out. I also had a very thin piece under the main plate, but that wasn't secured in any way. Removing the 4 screws the metal part should come loose. You don't need to remove the black screw as that's holding plastic part which isn't in the way.

To remove the wind lever first remove the screw holding the plastic cover from the bottom. Once the plastic cover is removed you can just unscrew the nut holding the metal part, but be careful as if you rotate the lever mechanism too far you may bend some springs. Having removed the metal part we are now faced with the same funny looking nut, which we need to remove.

Having removed all three parts we can now unscrew the 4 small screws and the 1 larger one near the winding mechanism and carefully remove the top part.

# Bottom part

Removing the bottom part is way easier. So much so that I don't even need to show an image. All you need to do is unscrew the 4 small screws and carefully remove the bottom part.

# Front part

Now sadly here I don't have *any* good photo, but I'll still try my best.

(Yes this is taken from the first photo)

First thing needed to be removed is the leather covering on both sides. When I removed mine one of them had their underside fall apart, but after attaching them with some 3M tape it seems to be ok.

Next up we need to remove the timer lever. The plastic button can just be pulled out. We can pry it out using a flathead screwdriver or a debit card. Once the button is out we'll be faced with another funny looking nut. This one should come out easily compared to the other two. With the nut out we can fully remove the lever.

Last step is to unscrew the four large screws on the front side. After that we can slowly remove the front part. We'll need to do it slowly as a wire is attached to it from the inside of the camera. It's secured using a small flathead screw.

Repairing the electronics

After poking around with a multimeter I came to the conclusion that I won't be able to fix them and so I decided to rip them out and make my own.

The electronics ended up being just an Atmega328P with an Arduino bootloader. It scans the currently set shutter speed and whether the shutter is open and uses the millis() function to time when the shutter should close. The camera uses an electro-magnet to hold the shutter open. The microcontroller controls the magnet using a transistor to protect it.

The red circle is the trigger from which I read whether the shutter is open.
The orange circle is where the flash LED is hooked up. I use it to signal whether the electronics are ready.
The green circle is where the trigger button completes the circuit when held down. Fully pressing it you trigger the mechanical shutter open mechanism.
The blue circle is a random buck-boost converter I found. I don't know if it is safe to use with an 4LR44 battery.
The cyan circle is the electro-magnet used to control the shutter.

Does it work?

Yes, yes it does.

If I ever do get around to improving this I'd like to get rid of the Atmega328P and use something smaller as it barely fits. Another cool thing would be to reimplement autoexposure and the indicator LEDs.