Bronica SQ-Am problem

I have been experiencing a problem with my SQ-Am lately. It fires for several shots, then fails mid-way through the firing sequence. I've checked the batteries, both the AAs and the small one, and they are fine. The backs I am using seem fine. I've tried two different types, just in case. Taking the batteries out and back off, and repeated attempts at firing the shutter eventually clears it. The motor sounds very healthy.
There was a thread about a similar problem with a Bronica camera, perhaps two years ago. The solution was to lubricate a linkage in the camera body. The only problem is that I cannot find that thread. I've tried various search options without success. Does anyone recognise the problem, or the thread I am looking for?
Thanks for any advice,
Alex.

Alex, many years ago, with a practically new ETRSi but a used magazine, I experienced intermittent shutter operation, in a single roll I might get a number of shots no problem, but then a number of no-shutter operation shots...no shutter-close confirmation light in the viewfinder. I had no problems with other film magazines that I had.

Bronica instructed me to send in body+lens+magazine. The problem which was resolved by Bronica's shop (before Tamron takeover) was that the magazine's 'film-advanced' interlock pin protruded too far into the body of the camera, which prevented the reflex mirror from swinging up FULLY, which then failed to allow the shutter to operate. The fix was for Bronica to shorten the film magazine's interlock pin very slightly, and the problem went away.

My old problem sounds reminiscent of your current issue...fires for several shots,then fails mid-way through the firing sequence!

Hi, and thank you for the response. These are the same symptoms, but I tested the body alone last night by firing it without a back attached. Sadly, the problem persists. I read through as many old threads as I could find, and I noticed your earlier posts about the back problem. That caused me to try different backs, and then without. I do recall, however, there was a thread identifying a problem with a small linkage in the mechanism that surrounds the lens mount on the body. There were photos attached to show the problem part, and where to lubricate. It's not the gold contacts, but a moving part. I may need to send it off for repair, but would do it myself if it is simply a lubrication issue. The motor sounds fine when it is working.
Alex

Since you tested with no back at all, and encounter the same issue without back, I would suspect the mechanical linkages within the body are in need of adjustment or lubrication. Without an official repair facility from the distributor, I am not able to recommend a knowledgable repair shop qualified in Bronica.