Beaulieu 4008 ZM II light meter.

[bakasutchi]

I have been putting some rolls of Ektachrome 64t through my Beaulieu with some nice results, and have been encouraged that all seemed to be working well, until! I have just finished a roll of Tri-x which I rated at 160 asa with the filter in. It seems to be underexposed by at least 1 stop. After checking the meter without film by rotating the asa dial, increasing the asa causes the needle to gradually rises until about 160 and then the needle jumps about. With the speed dial there is a similar fault when increasing the filming frame rate the needle moves accordingly until after 24 fps when it hardly moves. The frame speed does physically increase but the meter does not relate to the decrease in light after 24 fps. I have a schematic that shows a potentiometer as part of the asa and speed setting dials. Is there just one pot that is connected and could be causing both results? Could it be that the carbon track is faulty or dirty, is there any way of cleaning it or is there a more common cause of this sort of fault. I would appreciate any thoughts or answers on this subject.
Stuart.

[bolextech]

Hi Stuart,

If you can figure out how to remove the left side cover, you will see how the ASA potentiometer works when you change both the ASA and the running speeds. Like you say, a faulty or dirty carbon track would cause intermittent readings on the meter. Also, the nameplates frequently become unglued from the dials and this could also cause exposure errors. Cleaning the tracks and the contacts would certainly help. You can apply a minute quantity of electronic contact cleaner and work the dials from one end to the other a few times.

Good luck!

Cheers,
Jean-Louis

[bakasutchi]

Thanks for your help again, I shall give this a try. I have bought some switch cleaner which I will apply carefully. I am familiar with removing the case side, also information from you a while back. Thanks. Stuart.