ETRSi - 120 back problems

[spolly74]

I've done a fair amount of searching, without any luck. I'm hoping someone here will have a suggestion.

I have a Bronica ETRSi with two 120 backs. One of the backs tends to have problems mid-roll. Usually what happens is that the film simply won't advance. It feels like it does, but it doesn't. The winder winds and feels normal, but the frame indicator doesn't advance, and I end up with multiple exposures. Eventually, it will "kick in" and start advancing again.

The shutter works fine, the dark slide is out, the multi-exposure switch is set to single exposure. I haven't had problems with the other back, so I'm assuming it's a back issue. I'm reluctant to just buy a new back and assume its fixed, because it kind of stinks when it freezes up when I'm out and about.

Any suggestions for things I can check/do?

 

[paul ron]

Does this happen with other backs or just this one particular back? If it is only this back, it sounds like the film advance gear is stripped. It's a wafered notched soft metal that a pawl grabs. Once stripped, throw it away, it's cheaper to buy another back.

If it happens to all backs then the body has an issue with the small gear that aligns with the gear on the back. Check it for damage?

 

[CD55]

Have you tried using the 120 film insert with the other back that you have? If it still happens then that insert is bad and you can buy just an insert instead of the whole back which will save you some money.

 

[spolly74]

Have you tried using the 120 film insert with the other back that you have?

I haven't tried that - I will, thanks. For some reason, i'd been thinking that the gear was part of the back itself. Looking at it closer I see it's part of the insert.

 

[paul ron]

Not all inserts are compatable with all shells. Swapping inserts can cause another line of problems.

That gear you see might be one problem but not generally the cause if it is in good shape on visual inspection. The internal gear that mates with it should also be inspected for damage.

The waffer inside the the counter mechanism is most likely the cause in 9 out of 10 back failures not advancing film properly.

*Try another back (don't swap insrets) n see if it has the same symptoms, this way you'll eliminate the body to back interface gears?

As you say the other back works, the one that is slippping is a junker, throw it out n get another to save you alot of grief.

If you have a small screw driver handy, peel off the leatherete n open the side with the counter n see it work for yourself? Notice the counter wheel has slots, that is the waffer gear I am telling you about. Once it is stripped or damaged, it is junk n can't be replaced.


.

 

[jamesgignac]

I agree that you should replace the back though I would always swap inserts with my system (had a couple of handy little Bronica insert holders that attached to a belt, so I assume Bronica meant for the inserts to be interchangeable) and never had any problems. Buying a new back is not usually much more than buying an insert so see what you can find out there.

Don't throw out the old back - it's fun to open up and experiment on 'junk' like this so that you'll have a better idea of what to do in the future if something new goes wrong.

 

[paul ron]

If you examine the inserts and shells you will find they are not all created equally. Swaping inserts asks for light leaks, as the one insert has seated the seals to itself n it's irregularities.

A back will cost you as much as an insert.

 

[spolly74]

Thanks everyone. It seems like one or more new backs is in order.