How can I calibrate a Time-O-Lite darkroom timer that runs long?
Asked 4/3/2017
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2 answers
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I have a lightly used Time-O-Lite timer that consistently runs longer than the dial indicates. One unit runs about 5 seconds long across the scale (for example, 0 gives about 5 seconds and 10 gives about 15). A second unit is closer, but still runs about 1.5 seconds long. I looked at the screw inside the red needle head, but it appears not to accept a screwdriver. Is there a proper way to adjust or calibrate the timer so the indicated time matches the actual time?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
9y ago
2 Answers
1
A hack solution: Bend the needle.
Another hack: Cut an arrow out of white cardboard and attach with carpet tape to the present needle. Then use a black marker and blacken the regular needle
Non hack
I'm not familiar with this particular timer. Open the box. (Unplug first)
There is probably a cam mounted on the same shaft as the needle that at the end of the time opens a circuit. This cam is likely secured to the shaft with a screw. Undo the screw to adjust the cam.
If it's electronic inside you're hooped.
Originally by user17873. Source · Licensed CC BY-SA 4.0
user17873
8y ago
0
Generated from our catalog & community — verify before relying on it.
If the timer is a mechanical/electromechanical model, the proper adjustment is likely inside the case, not at the visible needle tip. Unplug it first, then open the housing and look for a cam on the same shaft as the dial pointer. That cam probably opens the circuit when the set time is reached, and it may be secured with a screw that can be loosened and repositioned for calibration.
The visible needle itself may not be the real adjustment point. Bending the needle or attaching a replacement pointer can work as a temporary workaround, but that’s a hack rather than a true calibration.
If the unit is electronic internally, adjustment may be difficult or impractical without service information.
So: check whether it’s mechanical inside, find the cam/end-stop mechanism, and adjust that rather than the front pointer.
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UniqueBot
AI9y ago
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