mikec
21-Apr-2007, 05:12
Question for the shutter experts:
I have recently bought a used 75mm f8 Schneider SA in a Linhof synchro-compur 0 and found that the low shutter speeds were very slow, the 1sec completely sticking. Looking around this and other forums I have seen that flushing any gunge is usually all that is needed to fix this. So I decided to take the plunge and started by inspecting for possible damage.
After removing the retaining ring, shutter speed ring ,facia plate and the shutter speed cam plate, I could see what appeared to be a liberal quantity of graphite grease applied to the main spring and that some had migrated onto the surrounding surfaces. As I had not read any reference to the use of such grease I thought it a possible source of a problem. I therefor removed the cocking rack and took out the timing gear set to give it a bath in lighter fluid and cleaned up the mainspring without removing it. I also put a little solvent on all the other pivots and then reassembled.
problem 1
When putting back the timing gear set I found that the shutter could not be cocked. This turned out to be due to the tip of the timing gear block preventing the mainspring gear plate from turning. On looking at the timing gear I noticed that the pin which engages in the speed cam plate was at the deapest point in its slot but remembered that before unscrewing the unit it had been a little up the slope. After removing the unit again I could see that by pushing the pin up the slope I could move the part that had blocked the main spring. So, thinking that I had solve the issue I slid the pin back up the slope while reinserting and screwing down the unit. Now I could see that the main spring gear was free and I could tension the shutter ( I did not do this fully while disassembled as the cocking leaver return spring pops off its post rather easily). I reassembled everthing and tested the shutter.
problem 2
The 1s, 1/2s and 1/4s speeds are now correct, but the 1/8, and 1/15 appear to fire at about 1/125s. 1/30 to 1/500 seem OK.
So I disassembled it again and when I excersized the speed cam plate without the ring being present and I could see that speed selection pin which follows the cam, was not following into the deeper cam recesses. This is due to the fact that adjustment I had had to make above, had prevented the pin getting to the base of the slope on the timing gear set top plate. grrrrrr!!!! Needless to say I tried to rebuild, but with the same result.
I am sure there is a simple solution to this as the only piece I removed, was the entire timing gear set which is held by just two screws with no possibility of adjustment I can see.
Does anyone who has pulled these apart know the answer, or should I pack it off to one of the experts?
I have recently bought a used 75mm f8 Schneider SA in a Linhof synchro-compur 0 and found that the low shutter speeds were very slow, the 1sec completely sticking. Looking around this and other forums I have seen that flushing any gunge is usually all that is needed to fix this. So I decided to take the plunge and started by inspecting for possible damage.
After removing the retaining ring, shutter speed ring ,facia plate and the shutter speed cam plate, I could see what appeared to be a liberal quantity of graphite grease applied to the main spring and that some had migrated onto the surrounding surfaces. As I had not read any reference to the use of such grease I thought it a possible source of a problem. I therefor removed the cocking rack and took out the timing gear set to give it a bath in lighter fluid and cleaned up the mainspring without removing it. I also put a little solvent on all the other pivots and then reassembled.
problem 1
When putting back the timing gear set I found that the shutter could not be cocked. This turned out to be due to the tip of the timing gear block preventing the mainspring gear plate from turning. On looking at the timing gear I noticed that the pin which engages in the speed cam plate was at the deapest point in its slot but remembered that before unscrewing the unit it had been a little up the slope. After removing the unit again I could see that by pushing the pin up the slope I could move the part that had blocked the main spring. So, thinking that I had solve the issue I slid the pin back up the slope while reinserting and screwing down the unit. Now I could see that the main spring gear was free and I could tension the shutter ( I did not do this fully while disassembled as the cocking leaver return spring pops off its post rather easily). I reassembled everthing and tested the shutter.
problem 2
The 1s, 1/2s and 1/4s speeds are now correct, but the 1/8, and 1/15 appear to fire at about 1/125s. 1/30 to 1/500 seem OK.
So I disassembled it again and when I excersized the speed cam plate without the ring being present and I could see that speed selection pin which follows the cam, was not following into the deeper cam recesses. This is due to the fact that adjustment I had had to make above, had prevented the pin getting to the base of the slope on the timing gear set top plate. grrrrrr!!!! Needless to say I tried to rebuild, but with the same result.
I am sure there is a simple solution to this as the only piece I removed, was the entire timing gear set which is held by just two screws with no possibility of adjustment I can see.
Does anyone who has pulled these apart know the answer, or should I pack it off to one of the experts?