My 4x5 CG has developed a quirk...I received it with broken rear bed rails, replaced them, got things aligned & smooth.

Today I noticed the focus tension is fine if the front standard lock is loose (the flip lever that is used to both slide the standard out to 'infinity' and is located by the L-R shift lock).

If I lock the standard, the focus tension greatly increased.

I may have tightened the screw under the lock lever a while ago when I thought it was TOO loose.

Does this sound more like a tension adjustment problem or a bent/alignment-again problem?

Thanks

Murray

1. With Front standard lock lever in the loose/center position does the yoke travel the full length of travel with the focus knob smoothly with the same amount of tension?

Yes=procede to next test step/question.

No=check both left and right bed blocks and guides with a square and set them square to the bed. With a straight edge across the foward end of the yoke is it parallel with the end of the bed? If no check that focus shaft is equal distant from the ends of the yoke and correct as needed.


2. Lock the front standard at 1/3 the distance from the yoke link to the front edge and run the yoke the full length of the bed, reposition the front standard and lock at 2/3 the distance from the yoke link and the front edge and run the yoke the full length of the bed. Did the focus tension increase and remain the same the full travel of the yoke on the bed with the stnadard locked in both positions?

Yes=Does the front standard try to twist in the direction that you are moving the lock lever when positioning the lock lever to the locked position? Yes=tension too high, adjust tension. No=Does the lock lever reach the mechanical limit of travel with equal pressure on the lever? Yes=tension setting good. No=tension too high, adjust tension.
If front standard lock tension is correct then loosen the screws on one bed block/guide assembly 1/4 to 1/2 turn and while mantaining squareness to the bed move the block .0001 to.0005 inches from yoke and tighten and recheck operation.

NO=Recheck bed block and guide installation and correct as needed.

If you do not have a small square that will fit in the tight areas of the bed then use two small straight edge or rullers. With one flush to the end of the bed and the other flush to the bed block slide the end of the one against the bed block to just touch the one flush to the end of the bed, they should be fully flush the width of the bed block straight edge.

The serivce manual shows no connection between the front standard lock and the focus tension, it just states that the tension on the yoke should be tight enough that the yoke will not slide any with the bed held vertically, focus lock off.