Rolleicord Compur timing adjustments

[KiyoKiyo]

Heya all

I'm servicing my Rolleicord, I've dissassembled, cleaned, lubricated, and am at the adjustment step of CLA.
My 1/1 is near bang on (997ms!)
My 1/500 is as I've read most expect of a leaf shutter (~1/280)

My 1/15 however... is a different beast. It's currently running at 1/180.
I've attempted to put a slight force on the adjustment pin a few times, but it doesn't seem to be affecting the timing.
I managed to get it to run 1/8 on the 1/15 setting one singular time, but I couldn't leave well enough alone, and haven't been able to reproduce that.

Am I missing something? I've got the compur manual but it doesn't seem to mention this scenario

 

[OAPOli]

Synchro Compur?

The pallet is released, so 1/15 runs at 1/250. The pallet cam is clockwise from the speed cam. I think you'll need to shift the speed governor so that the pallet lever drops in the deeper cutout at 1/15. Bending the pin is for small adjustments only.

 

[KiyoKiyo]

pallet cam

Sorry, having trouble identifying which one is the pallet cam/lever

Is the yellow circled arm the pallet lever? I've been adjusting the red circled pin for context

I assume by speed governer you mean the small plate with the cutouts to restrict the movements.

 

[Dan Daniel]

How are higher speeds? 1/60, for example?

You are on the right track, most likely. Bending that pin is the answer. And it can be very very touchy. I will cock the shutter, move the speed cam toward 1/30 to get the pin to slide down the ramp a bit, and grab it with smooth tipped needle nose pliers. Then give a slight bend one way or another. Keep the pliers on the upper straight part of the pin, not grabbing the wider base flange. If I try to bend without cocking the shutter, the pin is too close to the outer edge for me to get much movement.

'Much' being very relative here! Small small bends. It is possible to break that pin off.

When the shutter is not cocked and you move to 1/15 second, then cock the shutter, you should see that pin move a very small amount. Just a touch. If it is hitting the speed cam before cocking, it will be too fast. If too far away, too slow. And we are talking in 1/100s of a millimeter. I find watching the little movement toward the came that shows me how far off the cam the pin is is a good check on things.

There are two springs in the escapement that are prone to come off their settings. At each end for the two dark gray parts that curve down. But it soulds as if yours are fine.

Patience and more patience.

 

[OAPOli]

Red: detent pin
Yellow: pallet lever
Both are on the speed governor, also called retard gear train, escapement, etc...

The plate that goes on top is the cam ring.

On your second photo (set at 1/500) you can see the detent pin in the speed cam, as well as the pallet lever in the pallet cam at 5 o'clock. At 1/15 the pallet lever should drop down in the pallet release cam where it becomes wider. At 1/15 and 1/250, the speed cam puts the detent at the same height, so if there is no retarding action provided by the pallet (which becomes connected when the lever drops) they will run at the same speed.

 

[KiyoKiyo]

How are higher speeds? 1/60, for example?

1/30 and above are spot on.

escapement

Ah! that's the name I knew it by

pallet lever drops in the deeper cutout at 1/15.

Testing it again, it is dropping into the deeper groove at 1/8 and 1/15, but still running fast, is it possible I misaligned something in the speed governer/escapement during reassembly? A spring or some such that maybe isn't pushing on the lever with enough force?

1/4 seems to roughly work (1/6), but that would suggest that the pallet lever is dropping in just fine, and engaging the mechanism, no?

 

[Dan Daniel]

1/30 and above are spot on.

Ah! that's the name I knew it by

Testing it again, it is dropping into the deeper groove at 1/8 and 1/15, but still running fast, is it possible I misaligned something in the speed governer/escapement during reassembly? A spring or some such that maybe isn't pushing on the lever with enough force?

1/4 seems to roughly work (1/6), but that would suggest that the pallet lever is dropping in just fine, and engaging the mechanism, no?

I'm pretty certain it is the pin. I've seen this dozens of times. Did you look if the pin moves when set to 1/15 and you cock the shutter? Small nudges and it will pull into correct timing. And yes, 1/6 at 1/4 makes sense, it's a logarithmic effect.

 

[KiyoKiyo]

I'm pretty certain it is the pin. I've seen this dozens of times. Did you look if the pin moves when set to 1/15 and you cock the shutter? Small nudges and it will pull into correct timing. And yes, 1/6 at 1/4 makes sense, it's a logarithmic effect.

10 minutes of fettling later, I've got
1/1: 1.37
1/8: 1/6.3
1/15: 1/12
1/500: 1/302
I didn't have to touch the pin, just adjust the whole escapement backwards and forwards
some, I could probably dial it in further, but I'm going to test the rest of the speeds and see how far out it is from here.

 

[OAPOli]

@KiyoKiyo I think @Dan Daniel is correct: the detent pin regulates pallet engagement when the pallet lever is dropper. But if you can get good speeds without bending the pin it's better; this thing is fragile.

 

[Dan Daniel]

To set speeds, 1) rotate escapement to get 1 second. 2) bend pin to get 1/15. 3) adjust 1/500 pin if needed to get full clearance of main spring. 1,2,3 in that order. tHAT'S it.

So moving escapement and getting 1.37 for 1 second tells you that the pin is too close and needs to be bent away from the center.

Now in reality most people will use 1/30 to 1/250 for 95% of shots so if those are close and you are happy, seal it up and go shoot.