Shutter problem, power related?

[rubbernglue]

I now have two cameras with pretty much same kind of problem, and I am sure this have happened to several but it is kind of hard to find threads related to this.

I first noticed this on one of my old Mamiya M645 housings when suddenly it does not fire (or at least not properly). On the mamiya the shutter actually fires, but it remains open as if the battery is taken out - but I then hit the "battery check-button" and the shutter retracts. The Battery check-button also lights up the lamp (I therefore know it has power). When this occurrs I have taken out the battery and remounted it and it may work again. Recently I had this problem and I didnt get it to work and started to take it apart to reach its electronics and suddenly when mounting the battery it started working again, but I dont know for how long.

I also have a Bronica EC-TL which have started to be similar, however it doesd not fire at all when I hit the button, I take the battery out and back and it starts working for a few shots and then it fails again. This is very frustrating of course.

I have noticeds that these cameras uses a (kind of) large electrolytic capacitor, and I know these have a limited lifespan and as it works like a battery, it works bedst when brand new. I am planning to replace these capacitors based on that feeling, but I dont KNOW if this component is at all related/connected to anything that might cause this problem or not.

Does anyone have any input in this matter, or perhaps a different thread that I might have missed?

 

[shutterfinger]

Battery check lights on most cameras are worthless. The battery check does not put the battery under load therefore the reading is mute.
The 6V battery used in these cameras should read 6.5V to 6.6V when new on a volt meter. When they read 6V or less they need replacing.
If I were having problems and the battery read 6.1V I would replace it.

 

[rubbernglue]

Hmm so you dont think it has anything to do with old components?

 

[MattKing]

What type of battery are you using?

 

[rubbernglue]

I am using the 4LR44 batteries, and in some situations I have taped 4* LR44 batteries together, but they get a little small and is typical to loose contact from time to time.

Interesting regarding corrosion.. is there anything you would replace/change to minimise this effect?

 

[rubbernglue]

Great, will do! How about the capacitor, what is actually its job?

 

[shutterfinger]

Do you have fresh batteries?
Yes-what voltage do they read?
No- get one.

Do you have a volt meter?
Yes- proceed to the next step.
No- buy or borrow one, they do not cost that much.

Open the camera so that you can access the circuit board and still operate the camera.
Measure the battery with it disconnected from the camera and record the voltage.
Connect the battery to the camera. With the camera turned off measure the voltage of the battery, it should be the same as it was out of the camera.
Turn the camera on, wait 30 seconds then measure the battery again. It should be as before to a few tenths of a volt less.
Measure the battery voltage at the circuit board. It should be the same as it is at the battery.

While monitoring the battery voltage activate the meter then trip the shutter. Voltage drop should be 1 volt or less.
Camera circuits are current dependent and if operating correctly with a good battery will only drop a few tenths of a volt. A bad battery or failing components will cause a large voltage drop.

Replacing parts without doing any test is chasing wild geese. You might get lucky.

 

[rubbernglue]

Replacing parts without doing any test is chasing wild geese. You might get lucky.

You are so right, however I thought that perhaps replacing that capacitor would not damage anything but might enhance something else

 

[John Koehrer]

Two things, Shutterfinger said BC lights are useless. Better Believe It!
#2 a Voltmeter doesn't necessarily load the batteries, which means they may read good but will be
marginal or no good in camera,