bill santen

Some of your symptoms sound similar to some problems I had with my NPR motor, assuming they are both the same.

I know it's not very clear on this snap, but this is the motor on my camera:

 

My problem was that everything would run fine, then for no apparent reason the motor would just stop. In this condition the switching FET bolted to the top of the box would heat up (thus warming the box). If the motor was removed from the camera then it was possible to see the motor shaft would turn slowly, but it didn't have any power behind it to drive anything.

 

With a bit of fiddling I seemed to track the problem down to the green connectors used to connect the motor and its feedback encoder to the control circuit board inside:

 

 

These appear to be unavailable these days, and there isn't much space in there to fit alternatives. I did solve that problem by carefully applying "silver conductive paint" to each of the contacts, then pushing the two halves together whilst the paint was still in its liquid state.

 

Once I'd sorted that problem, I then found it would run fine for 100's of ft of film before suddenly starting to play up and stall for no apparent reason. If the switch was turned off and the manual advance knob given a tweak then suddenly you'd see the motor wake up and return the shutter to the 'park' position again. I never did quite find a definate reason for that one, but think it might be related to load on the camera.

 

I found that the 'problem' seemed to be related to how well seated the motor was on the camera, and the exact angle of alignment between the two. By shuffling the motor position I was able to make it complain a lot more frequently, or almost not at all. Since sending the camera off for service/lubrication I don't appear to have had a repeat of the problem (touch wood).

 

I was put in touch with a chap here in the Uk that does camera electrical repairs, and is used to working on the NPR motors. He explained how circuit diagrams have never been available, and even supposedly motors of the same type have different value components - suggesting each one was tweaked on assembly. The green connectors going a bit dicky is a frequent problem, and if he can't fault find the circuits fairly quickly then it works out more effective to replace the circuit with a board of his own design.

 

If you're not 'into' electronic engineering, then there's nothing to see and nothing to adjust inside the box, but with a bit of care and a screwdriver it shouldn't be beyond someone being careful to open it up and wiggle the green connectors to see if they've got an intermittent connection, or dose them with conductive paint to see if it sorts things.

 

You mentioned that the motor runs fine when it's disconnected from the camera. Does it do the problem if you load the output wheel by rubbing it against something, or carefully squeezing with your fingers whilst not on the camera? If the camera hasn't been serviced in a long time then perhaps that's getting a bit stiff and needs a touch of oil? The fact that your times gradually reduce until you let it rest for an hour or so suggests something in the circuit is heating up (not just the switching transistor bolted to the motor box).

 

Sorry I can't really say what's wrong, hope you get to the bottom of the problem.

Any suggestions are very much appreciated:

My eclair NPR crystal sync motor worked fine yesterday and this morning a disturbing pattern began. The problem occurs with or without the film magazine.

1. sync speed for 45 seconds, wobbling sound from the shutter, whine, motor disengages and runs at 1/8 speed-

2. after 45 seconds, restart camera and the motor is normal for 30 seconds

3. 15 seconds

4. 5 seconds

The square controller box becomes hot when the motor slows-

If the motor rests for an hour or more, the cycle can be repeated.

When the motor is removed from the camera body, the problem disappears.

Help!!

Thanks

Bill