schneider woes

Hello,
So one of the lenses i have for my cambo is a schneider super-angulon 65mm. this lens is obviously a very nice german lens. Well it's got a problem. The glass is totally fine, no fungus, scrathes, split coatings, cracks, etc. the aperature works fine and everything. However, whenever i go to cock the shutter, once i release the lever, the shutter fires off. While this wouldn't be a problem if the shutter fired accurately to the time that i set, it does not, it fires as if it's in bulb. this problem can be remedied if i hold the shutter release lever the opposite of firing direction while i cock the shutter. The problem is intermittent, and luckily i'm careful enough to keep the dark slide closed while i cock the shutter, but does anyone know a simple fix to this? I don't want to pull apart such a nice lens, and i don't want to have to take it to a camera shop...
thanks,
Austin

How long has it been since the shutter has been serviced? More than 25 years possibly? It's probably time for some routine maintenance, and it will probably cost around $85. Better to send it in and have it done right than to find a temporary solution and discover other problems along with the main one, like speeds that are probably inconsistent.

it has been a while, my dad got the camera from working at an estate sale, and it sat in a basement for probably 15 years. so its been a while... 85 isn't so bad...