This may help someone else seeking to restore/repair an old darkroom timer. I believe many mechanical timers use a similar Intermatic timer motor described here.
I received as a gift a complete set of darkroom gear that dates back to 1983 or so. The gem in the collection was a Graflex Super Graphic camera. However, I also received a Beseler 23C enlarger that had been equipped with a Dual Dichro 23 head and stabilized power supply.
With the enlarger came this Omega timer, clearly patterned after the venerable Gralab models. Initially it worked fine, but gradually it began having startup issues. Eventually it failed completely.
I opened the case and found that the timer mechanism is run by this simple Intermatic timer motor. These things are used in water softeners, pool timers, Christmas light timers, appliance timers and lots of old and current equipment.
Oddly, I could hear the motor running, but none of the gears were turning. I called Intermatic (near my house), but they said the motor was discontinued and no longer available. I was ready to pitch the timer, when I decided to do an Internet search to see if anyone had discovered a component-level repair for the motor. Sure enough, someone had!
Similar motors are use in an old clock that used metal ball bearings to keep time. A man sells the replacement parts needed to replace the bad parts. More importantly, he has prepared an excellent YouTube video on how to service these motors.
It turns out nearly all of this style of Intermatic motor use the same armature and idler gear assembly beneath the top cover. Only the underlying visible gearing is different to provide various levels of torque and rotation rate. The common parts may be accessed by bending two of the tabs and popping off the cover.
The failure mode on all of these motors is the amber-colored small gear mounted on top of the motor rotor/pole piece on the left. With heat and age, the plastic decays and the teeth just crumble away. That is what happened to my timer. Here is the gear. Almost no traces of the teeth can be seen.
The other idler gear has a small arm mounted to the bottom. This bar rotates around the gear hub and sets the rotation direction of the motor, depending upon its orientation on the shaft in relation to the armature assembly. Mine was stiff and barely moved.
In addition, there is an oiler disk spacer beneath the armature that has a felt pad to supply lubrication to the fixed shaft as it rotates about it. That seemed ok.
The guy on the internet sells the two replacement gears for a fairly steep price, considering what they are. I decided to look around the house for an on-hand cheaper (read FREE) solution. I found this old garden lighting timer in the junk box made by Intermatic. It looked promising, so I opened it up.
Inside was a motor that looked very similar to the one in my darkroom timer.
I opened the cover and removed the two gears. They fit perfectly! The new armature assembly uses self-lubricating plastic, so the old oiler disk is not needed (and would not fit). I cleaned all the old oil and gunk off of the two fixed shafts and installed the gears, being careful to position the swing arm for correct rotation. The video explains all of this very well. I put the cover back, bent the retaining tabs back and I now have a quiet and fully-functioning timer. Total cost: $0.00.
Here is the video that describes the entire process at length:
Best regards,
Don
I received as a gift a complete set of darkroom gear that dates back to 1983 or so. The gem in the collection was a Graflex Super Graphic camera. However, I also received a Beseler 23C enlarger that had been equipped with a Dual Dichro 23 head and stabilized power supply.
With the enlarger came this Omega timer, clearly patterned after the venerable Gralab models. Initially it worked fine, but gradually it began having startup issues. Eventually it failed completely.
I opened the case and found that the timer mechanism is run by this simple Intermatic timer motor. These things are used in water softeners, pool timers, Christmas light timers, appliance timers and lots of old and current equipment.
Oddly, I could hear the motor running, but none of the gears were turning. I called Intermatic (near my house), but they said the motor was discontinued and no longer available. I was ready to pitch the timer, when I decided to do an Internet search to see if anyone had discovered a component-level repair for the motor. Sure enough, someone had!
Similar motors are use in an old clock that used metal ball bearings to keep time. A man sells the replacement parts needed to replace the bad parts. More importantly, he has prepared an excellent YouTube video on how to service these motors.
It turns out nearly all of this style of Intermatic motor use the same armature and idler gear assembly beneath the top cover. Only the underlying visible gearing is different to provide various levels of torque and rotation rate. The common parts may be accessed by bending two of the tabs and popping off the cover.
The failure mode on all of these motors is the amber-colored small gear mounted on top of the motor rotor/pole piece on the left. With heat and age, the plastic decays and the teeth just crumble away. That is what happened to my timer. Here is the gear. Almost no traces of the teeth can be seen.
The other idler gear has a small arm mounted to the bottom. This bar rotates around the gear hub and sets the rotation direction of the motor, depending upon its orientation on the shaft in relation to the armature assembly. Mine was stiff and barely moved.
In addition, there is an oiler disk spacer beneath the armature that has a felt pad to supply lubrication to the fixed shaft as it rotates about it. That seemed ok.
The guy on the internet sells the two replacement gears for a fairly steep price, considering what they are. I decided to look around the house for an on-hand cheaper (read FREE) solution. I found this old garden lighting timer in the junk box made by Intermatic. It looked promising, so I opened it up.
Inside was a motor that looked very similar to the one in my darkroom timer.
I opened the cover and removed the two gears. They fit perfectly! The new armature assembly uses self-lubricating plastic, so the old oiler disk is not needed (and would not fit). I cleaned all the old oil and gunk off of the two fixed shafts and installed the gears, being careful to position the swing arm for correct rotation. The video explains all of this very well. I put the cover back, bent the retaining tabs back and I now have a quiet and fully-functioning timer. Total cost: $0.00.
Here is the video that describes the entire process at length:
Best regards,
Don
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