Zenzanon 75mm PE Repair

Hi everyone,

I have a problem with a 75mm PE. With or without the battery, it has erratic speeds, including often just hanging open or not firing at all. Bulb is the only reliable setting. While I couldn't find a repair guide online, I took a crack at disassembling the lens, but couldn't get into the shutter housing. I was able to confirm continuity on the ribbon cable and that's about it.

I'm guessing it's just a matter of cleaning the magnet. I have a second lens in worse physical shape but otherwise functional (apart from the DOF lever) parts are needed. I'm new to MF lens repair, so I don't know how feasible Frankensteining these into one working lens would be. Any advice is appreciated.

Welcome aboard! I do agree it sounds like an intermittent fault involving the solenoid. Regarding the erratic speeds, does the lens do speeds that are shorter than the set exposure, or both shorter and longer? I.e. assuming it's a solenoid failure, does it release too early, or does it (also) stick?

koraks said:

Welcome aboard! I do agree it sounds like an intermittent fault involving the solenoid. Regarding the erratic speeds, does the lens do speeds that are shorter than the set exposure, or both shorter and longer? I.e. assuming it's a solenoid failure, does it release too early, or does it (also) stick?

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Thanks for the reply. It does both. It can stay open until I wind on, any speed above or below, or just shut and not fire. Applicable to all speeds. Occasionally it does fire at the right speed, but it's very rare.

Since posting, I was able to access the internals. I got the shutter loose, but couldn't remove it because the innermost linkage ring wouldn't come out, so it just floated inside. I just stripped both lenses and swapped the nicer parts onto the working core. Surprisingly easy to get the helicoid aligned, so much so that I'm unsure if I actually did it correctly. I also managed to get the DOF lever fixed, since it was just the linkage slipped away from the switch's prongs. Not that it matters now, since that part is now on the problem shutter. What a semi-waste of time!

Ah, so you've made one working lens out of two problematic ones - sounds good! Sounds like the problem with the original shutter might have been a mechanical issue rather than the solenoid. Mostly with solenoid problems on these shutters, the shutter is limited to its native fastest speed.

If the new/Frankensteined lens focuses correctly to infinity, the helicoid should be inserted OK.

koraks said:

Ah, so you've made one working lens out of two problematic ones - sounds good! Sounds like the problem with the original shutter might have been a mechanical issue rather than the solenoid. Mostly with solenoid problems on these shutters, the shutter is limited to its native fastest speed.

If the new/Frankensteined lens focuses correctly to infinity, the helicoid should be inserted OK.

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I haven't had a chance to test it, but it only had like 5 mating threads and most of them were wildly off, so I'm sure its okay. It's dead on with the focus index but is maybe a millimeter off from the aperture dot. As for the busted shutter, you're probably right. Even with the battery removed, it would stick open.

BoardsofCanada said:

Hi everyone,

I have a problem with a 75mm PE. With or without the battery, it has erratic speeds, including often just hanging open or not firing at all. Bulb is the only reliable setting. While I couldn't find a repair guide online, I took a crack at disassembling the lens, but couldn't get into the shutter housing. I was able to confirm continuity on the ribbon cable and that's about it.

I'm guessing it's just a matter of cleaning the magnet. I have a second lens in worse physical shape but otherwise functional (apart from the DOF lever) parts are needed. I'm new to MF lens repair, so I don't know how feasible Frankensteining these into one working lens would be. Any advice is appreciated.

Click to expand...

M. Vettore created some Bronica shutter repair guides. You can find them here:
https://ianbfoto.com/downloads-page/#