Bronica prism loose mirror?

rickbraun · Dec 22, 2022

My eye-level prism's mirror is apparently loose (rattles when shaken) (not stirred). Can anyone share any repair ideas or info on how the mirror is shimmed or attached?

reddesert · Dec 22, 2022

What kind of Bronica? There are several and the prisms are not all the same.

If it's an ETRS or SQ, the first things I would check are:

- Make sure the eyepiece lens hasn't come loose from its mount and fallen inside.

- If you remove the cover of the prism (screws on sides), the prism is usually held down by a plastic form. like a strap, with some foam and then a plastic shield between the foam and the glass (thank you Bronica; this prevents the foam from damaging the reflective coating). If the foam has deteriorated or the prism is loose for whatever reason, you can stuff some new foam or other shim material in between the shield and hold-down strap, and that should keep the prism from sliding forward once reassembled.

This is fairly simple for non-metered prisms. It might be similar for metered prisms but I haven't taken one apart.

Sirius Glass · Dec 22, 2022

A trip to KEH could get that mirror fastened down before it chips, cracks or breaks.

rickbraun · Dec 23, 2022

reddesert said:
What kind of Bronica? There are several and the prisms are not all the same.

If it's an ETRS or SQ, the first things I would check are:

- Make sure the eyepiece lens hasn't come loose from its mount and fallen inside.

- If you remove the cover of the prism (screws on sides), the prism is usually held down by a plastic form. like a strap, with some foam and then a plastic shield between the foam and the glass (thank you Bronica; this prevents the foam from damaging the reflective coating). If the foam has deteriorated or the prism is loose for whatever reason, you can stuff some new foam or other shim material in between the shield and hold-down strap, and that should keep the prism from sliding forward once reassembled.

This is fairly simple for non-metered prisms. It might be similar for metered prisms but I haven't taken one apart.

Bronica ETR non-metered prism. Having a difficult time removing the screws. Probably need to purchase better set of mini-phillips driver set. Any recommendations on those? Thanks for taking the time to respond.

grat · Dec 23, 2022

rickbraun said:
Bronica ETR non-metered prism. Having a difficult time removing the screws. Probably need to purchase better set of mini-phillips driver set. Any recommendations on those? Thanks for taking the time to respond.

Do NOT use phillips bits. You really do need JIS (Japanese Industry Standard) bits. Regular phillips drivers will chew the screw, which is an unfortunate rhyme.

Personally, I love my iFixit Pro kit-- it meets about 95% of the needs for disassembling cameras, and it includes four JIS driver bits.

rickbraun · Dec 23, 2022

grat said:
Do NOT use phillips bits. You really do need JIS (Japanese Industry Standard) bits. Regular phillips drivers will chew the screw, which is an unfortunate rhyme.

Personally, I love my iFixit Pro kit-- it meets about 95% of the needs for disassembling cameras, and it includes four JIS driver bits.

I'll get a set and investigate. Thanks

reddesert · Dec 23, 2022

There are sets made by Vessel that include various JIS screwdrivers that are pretty good price and easy to get on ebay or elsewhere. You likely need a #0 driver. Using a too-small driver will damage cross-point screws.

This page explains the difference between JIS and Phillips: https://www.vesseltools.com/handtools/screwdrivers/jis-japanese-industrial-standard

IME, the screws in the Bronica prism were not as unreasonably tight as some camera screws I have seen, and a good #0 Phillips driver would work if you have a careful hand. However, YMMV. Emphasis on good as there are a lot of cheap but low quality "precision" screwdrivers out there.

I think you need to take out about four screws to remove the prism cover, two in the front sides and two near the rear, but can't remember exactly where and I'm not near an ETRS at the moment. It wasn't too hard to figure out.

rickbraun · Jan 8, 2023

Update - purchased a set of JIS screwdrivers - worked like a charm to remove the 2 screws on each side of the prism cover. Internally, there is a cork pad, which had deteriorated. Applied a few layers of duck tape over the pad to increase its thickness (thus lessening the distance between the pad and the cover. Perfect fix - thanks to everyone for your responses and help.

ic-racer · Jan 8, 2023

Maybe of help:

Rollei 45 degree Prism Repair

I have had this 45 degree prism since about 1993. Recently it sounded loose, and the glass is rattling around.

www.photrio.com

Bronica prism loose mirror?

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