500 EL/X cycling and wont stop

A friend was asking if I knew what is causing a problem with his 500el/x (or m--he wasnt sure). He is

using a 9v battery adapter with new battery. He presses the shutter and it exposes the film, shutter on

lens remains closed, light baffle stays open and the film winding gear goes around and around and

wont stop until you turn the switch to L for lock, or pull the battery.

While I have heard of this many times before, I cannot for the life of me recall what causes it. He said

he just had the body cla'd by a competent (but not an expert on Hasselblads), a few months ago.

Anyone remember what causes this endless cycling? I suggested it might need adjustment, but wasnt

sure if it might be something with the 9 volt battery converter or something since I dont use them. The

lens is jammed in place, though I can probably unjam it when I see him. Thanks for any suggestions.

Had a look at the camera. It is a 500 el/m, not el/x, but has the newer plate release. Had a crappy

Neveready battery in it. Put in a fresh Energizer 9v battery, put the side plate on, took it off the Lock

position, and it immediately cycled correctly, including properly cocking the shutter. I guess a weak

battery prevents something from engaging. Hope this helps someone else.