Prontor SVS shutter problem

I have a 127mm Ysarex lens on a Prontor SVS shutter from a Polaroid 110b, on my home made 4x5 field camera. My problem with the shutter is that it will not stay open on the "B" setting when using a cable release. It works when I trip the external shutter release. Its a real PITA to focus, or do exposures longer than one second. Any suggestions on a remedy?

Rick

I have three or four of these shutters (same source as yours) and they all need work. I'm trying to convince myself to send them out, but I keep finding ways to work around the problems, like using the lens only when I can do a relatively short exposure. I'll be interested to see if a good CLA has fixed other people's problems.

What I've been doing, is tripping the shutter with the external, and while holding it, depress and lock the cable. It feels like I should have three hands to accomplish this, and sometimes takes two or three tries. I was just wondering if there was an easy fix to get the cable to work without the extra fuss.

Rick

My 127 Ysarex Polaroid shutter was crappy (but I love the lens), so I removed the Ysarex cells and screwed them into a Synchro-Compur P shutter, from a 135mm Schneider Xenar. The Xenar's are commonly found on Speed or Crown Graphics, usually inexpensive. Screws right in, works great!

You might first try a cable release that has a longer "throw." And, lastly, I have a 152mm Ektar that sometimes won't stay open on "B" until I give it a REALLY firm snap from the cable release. Once it is firmly opened, it then works on bulb.