Bronica Zenzanon PG 250 (GS-1) not firing

[Hassasin]

I've only owned GS-1 for a couple of months. Recently I got two of PG 250 5.6 lenses. One was said to have a firing problem (and I got it free, so no issue) second one was to be fine, but upon mounting it does the same as the free one, will not fire. I managed one shutter release, else it's just not going off. I have two other lenses, the 50 and 150, both working fine on same body, so it is not an issue with body.

Not asking for "return it" advice, not doable + lens is still like new, and price was right anyways, so am hoping to get it going or use as display item. With two I have perfect book ends, if it comes to that

But I find it interesting that two examples of this lens, both looking new, show same problem. Has anyone experienced similar issue with the 250 (or any other, for that matter, in GS line up0 ? It's odd to me and somehow it makes me think the 250 issue is not a coincidence, but possibly manufacturing oddity.

So far I've not found much on the net for PG lenses repairs or firing issues, except some reports on GS1 not firing in general. This appears to be isolated to lens itself.

 

[Hassasin]

To add, with mirror up switch I can release the shutter on this lens, meaning when MU switch is moved to position shutter fires. I'm not yet versed with how MU is linked to shutter mechanism as it appears to be doing a thing of its own (mostly be design, but also releasing shutter on this 250 lens)

 

[Truzi]

I've no real clue, but when I got my GS-1 the shutter wouldn't fire. I found a couple pins at the interface between lens and body were sticking in a bit. They are spring-loaded.

I wiped them with a dry cloth and worked them in-and-out a bit, and everything has been fine since.

Hope your issue is as simple.

 

[Hassasin]

I've no real clue, but when I got my GS-1 the shutter wouldn't fire. I found a couple pins at the interface between lens and body were sticking in a bit. They are spring-loaded.

I wiped them with a dry cloth and worked them in-and-out a bit, and everything has been fine since.

Hope your issue is as simple.

Thanks, I've played with them a bit but not all that much, will probably try some more. I know I can trip shutter manually with lens off, and also, when I release camera shutter I hear a faint click, probably from electromagnetic trigger.

When I mount lens on body I get shutter off on first trigger, then no more. Only with MU lever, but that is likely because MU is an actual direct mechanical release.

I think I'm going to get a fresh silver oxide battery and see if this lens needs maybe more juice to get going. Manually I feel no difference how much pressure I need to get these lenses off vs. the other two that do work on the body without issues.

 

[reddesert]

I'm not clear on what is happening or not happening when you say "doesn't fire."

When you press the shutter button on the GS (or other electronic Bronicas) the body linkage that carries the lens shutter cocking pins should move toward the uncocked position, causing the shutter to close, and then at the end of its travel to open and stay open for a time timed electronically by the body. As you know (mentioned in post #4) the shutter can be tripped mechanically with the lens off, by depressing a little lever hidden behind the bayonet flange and moving the pin to the uncocked position.

When you flip the mirror lockup lever on a GS-1, with the body+lens cocked, it should send the mirror up and mechanically move the body linkage, but not all the way, so that the lens shutter winds up in the closed position. Pressing the shutter button will then cause the lens shutter to open for the desired time. (This makes sense since the MLU should not actually open the shutter.)

So it's not clear to me if you're saying that (without MLU) the shutter button doesn't cause anything to happen at all, or that it mechanically fires the linkage but the shutter doesn't open. Also, not clear if you're saying that the MLU lever itself causes the shutter to open, which shouldn't happen.

 

[Hassasin]

So it's not clear to me if you're saying that (without MLU) the shutter button doesn't cause anything to happen at all, or that it mechanically fires the linkage but the shutter doesn't open. Also, not clear if you're saying that the MLU lever itself causes the shutter to open, which shouldn't happen.

I can see how I may have caused confusion, will have to get back home and check actual shutter movement when using MU lever, so I need to get back on this.

I can trip shutter with lens off, it trips once after I mount the lens on body, does not on subsequent tries. This sort of supports the idea of battery being drained to a degree and one shot takes below required level. After an hour I get same once and nothing result.

Shutter release in itself is electromagnetic on GS1 but mechanical on other formats (shutter itself is tripped mechanically ). Hence I am thinking of testing this lens with new battery just to get that possibility out of the way, but I've read a case where problem was seemingly same as mine and new battery fixed it.

 

[itsdoable]

All the Bronica lenses trip mechanically, the electromagnet just holds the shutter open for anything longer than 1/500 sec. Thus they all have a mechanical 1/500 shutter speed (and T).

The GS1 body mechanism also has a mechanical release option with the lever to the right of the lens mount. That should trip your 250mm lens' mechanical shutter speed. If the electric release on the body is not working with that lens only, there may be a short in the lens electronics, causing battery drain when that lens is mounted, and that would prevent the shutter button from tripping the body, but the mechanical release should still work.

 

[Hassasin]

All the Bronica lenses trip mechanically, the electromagnet just holds the shutter open for anything longer than 1/500 sec. Thus they all have a mechanical 1/500 shutter speed (and T).

The GS1 body mechanism also has a mechanical release option with the lever to the right of the lens mount. That should trip your 250mm lens' mechanical shutter speed. If the electric release on the body is not working with that lens only, there may be a short in the lens electronics, causing battery drain when that lens is mounted, and that would prevent the shutter button from tripping the body, but the mechanical release should still work.

“Mechanical lever to the right of lens” you mean the MU lever, none other exists. Mechanically shutter trips, electronically does not.

And you keep saying what electromagnetic release does. You must be referring to the electromagnet within each lens, which is true for every Bronica of that vintage so all G, E and S lenses. Camera controls speeds after shutter is tripped though. But I read what I do.

Unlike other bodies, release on GS is also electric, I’m not going to argue whether this is a momentary contact or what Bronica calls it “ electromagnetic” as it is probably moot to problem at hand since I have no problems releasing other lenses.

But having two like new 250 lenses with exact same problem I find any shorting suspicious as being the cause. When I get to it I will check on that, never know it might be the case.

 

[Hassasin]

So it's not clear to me if you're saying that (without MLU) the shutter button doesn't cause anything to happen at all, or that it mechanically fires the linkage but the shutter doesn't open. Also, not clear if you're saying that the MLU lever itself causes the shutter to open, which shouldn't happen.

When MU lever is put back (MLU is turned off) shutter is released mechanically, this is how it works on GS1. I'm not sure if that was part of the confusion, but what it means is that, with my issue, shutter is released mechanically with MU lever (as it should be), but not electronically with shutter button.

I have some work to do on this, but first stil need to get a new battery first to get rid of that idea being, or not, a solution. Then get to electromagnet in the lens as I am reading about this being stuck sometimes preventing proper shutter operation.

All I know at this point is that mechanically there is nothing wrong. The fact two same lenses have this problem, might be leading to lack of use (250's are generally not frequent flyers) and shutter's electromagnet not having sufficient exercise time (there are still moving parts, so not necessarily an electronic problem).

 

[Hassasin]

Update:

Since I have two GS1 bodies I went to the second one, all lenses fired off, even if the 250 needed a few cycles to get started. But back to first body and 250 does not fire. Meanwhile I discovered same issue with the PG 50, so not an isolated case to the 250 at all.

Battery made no difference, as one body works fine on either battery and the other does not.

Now I have two bodies, one of which manages PG 150 fine, but my 50 and 250 is a no go on that body. That "half" working body is fine otherwise, and all other functions are good, just releasing lens shutter is not. Seems like trigger lever in the body does not have enough power to trigger some lenses, and I don't know how much is actually needed. All I can think as without lens everything is moving fine in that body.

 

[itsdoable]

“Mechanical lever to the right of lens” you mean the MU lever, none other exists. Mechanically shutter trips, electronically does not.

And you keep saying what electromagnetic release does. You must be referring to the electromagnet within each lens, which is true for every Bronica of that vintage so all G, E and S lenses. Camera controls speeds after shutter is tripped though. But I read what I do.

Unlike other bodies, release on GS is also electric, I’m not going to argue whether this is a momentary contact or what Bronica calls it “ electromagnetic” as it is probably moot to problem at hand since I have no problems releasing other lenses.

But having two like new 250 lenses with exact same problem I find any shorting suspicious as being the cause. When I get to it I will check on that, never know it might be the case.

The sequence of events when you trip the GS1's shutter button is as follows:
- The shutter button (and electrical switch) trips an electromagnet in the body that releases the mirror mechanism and mechanical lens coupling.
- at the same time, the electronics in the camera engage the electromagnet in the lens to hold the shutter open.
- the mechanical sequence in the body is as follows:
- the mechanical lever connecting the lens (that also cocks the shutter spring in the lens) slides to the shutter closed position
- the mirror lifts, as the does secondary shutter baffle
- the mechanical lever connecting the lens moves to trip the shutter open
-the electronic timer in the body cuts power to the electromagnet in the lens, which then allows the shutter to close.

The Mirror up lever, which is also the mechanical backup shutter release works as follows:
- flipping the lever to the mirror up position:
- mechanically trips the lever connecting the lens to slide to the shutter closed position
- the mirror lifts, as the does secondary shutter baffle
- the mechanical lever connecting the lens moves and trips shutter open
- since there is no power to the electromagnets in the lens, the shutter is tripped at it's 1/500 mechanical speed.

So, if the mechanical releases are working correctly, then the mechanical parts of the lens and body are OK.

Then electrical side is probably the issue.
If the shutter is not staying open for longer shutter speeds, then the issue is the electromagnet in the lens is not getting enough power. This is not your issue.
If the mirror is not going up, then the electromagnet that triggers the body mechanism is not getting enough power. Similarly if you trip the mechanical mirror up, then try the shutter release. This seems to be your issue.

The electromagnets in the Bronicas are NOT momentary pulse circuits (like a lot of later electronic shutters), and need a sustained high current during operation (pulsed system store the pulse energy in a capacitor, so they work with poor batteries - and use less power). As a result, they are sensitive to battery type and condition. For instance, if you set a shutter speed of 1 sec, the electromagnet in the lens must sustain an adequate current for the full 1 second. The manual recommends silver oxide batteries, as they are capable of sustaining a high current. I've had good success with Li-ion batteries too, but Alkalines often do not last long. If the battery is old or depressed, they often do not work. New silver oxide batteries that are past their due dates sometimes do not work.

Since you report that the body works without a lens, it appears that attaching the lens causes the system to draw too much current from the battery. This may be because the battery cannot handle the current draw, or that there is a short in the electrical system that causes excess current draw. Since you have 2 bodies, if the latter is the issue, you should be able to figure out which item is at fault - which body and/or which lens. (Olympus OM4T's were notorious for having resistive shorts, but I have not come across this issue in Bronicas)

I would start with a good battery, and work through the process to identify the root issue.

 

[Hassasin]

The sequence of events when you trip the GS1's shutter button is as follows:
- The shutter button (and electrical switch) trips an electromagnet in the body that releases the mirror mechanism and mechanical lens coupling.
- at the same time, the electronics in the camera engage the electromagnet in the lens to hold the shutter open.
- the mechanical sequence in the body is as follows:
- the mechanical lever connecting the lens (that also cocks the shutter spring in the lens) slides to the shutter closed position
- the mirror lifts, as the does secondary shutter baffle
- the mechanical lever connecting the lens moves to trip the shutter open
-the electronic timer in the body cuts power to the electromagnet in the lens, which then allows the shutter to close.

The Mirror up lever, which is also the mechanical backup shutter release works as follows:
- flipping the lever to the mirror up position:
- mechanically trips the lever connecting the lens to slide to the shutter closed position
- the mirror lifts, as the does secondary shutter baffle
- the mechanical lever connecting the lens moves and trips shutter open
- since there is no power to the electromagnets in the lens, the shutter is tripped at it's 1/500 mechanical speed.

So, if the mechanical releases are working correctly, then the mechanical parts of the lens and body are OK.

Then electrical side is probably the issue.
If the shutter is not staying open for longer shutter speeds, then the issue is the electromagnet in the lens is not getting enough power. This is not your issue.
If the mirror is not going up, then the electromagnet that triggers the body mechanism is not getting enough power. Similarly if you trip the mechanical mirror up, then try the shutter release. This seems to be your issue.

The electromagnets in the Bronicas are NOT momentary pulse circuits (like a lot of later electronic shutters), and need a sustained high current during operation (pulsed system store the pulse energy in a capacitor, so they work with poor batteries - and use less power). As a result, they are sensitive to battery type and condition. For instance, if you set a shutter speed of 1 sec, the electromagnet in the lens must sustain an adequate current for the full 1 second. The manual recommends silver oxide batteries, as they are capable of sustaining a high current. I've had good success with Li-ion batteries too, but Alkalines often do not last long. If the battery is old or depressed, they often do not work. New silver oxide batteries that are past their due dates sometimes do not work.

Since you report that the body works without a lens, it appears that attaching the lens causes the system to draw too much current from the battery. This may be because the battery cannot handle the current draw, or that there is a short in the electrical system that causes excess current draw. Since you have 2 bodies, if the latter is the issue, you should be able to figure out which item is at fault - which body and/or which lens. (Olympus OM4T's were notorious for having resistive shorts, but I have not come across this issue in Bronicas)

I would start with a good battery, and work through the process to identify the root issue.

Thanks, it helps, a lot actually. Have just read a case, from the days of actual factory repair available, in similar case the electromagnet in the body was replaced to fix it. I am at this point believing that body electromagnet is too weak and does not pull enough to trigger the lens. As lens works fine on another body, I can't see how the lens has issues.

I have now no time on hand to poke into the body, but as great as the camera is, if it is indeed the electromagnet, which I've no expectations there are replacement parts for, this must be the weak spot for the GS1, and possibly THE reason for many "tea" GS1 bodies out there.

Camera in question does not look used much. Hopefully I get it fixed (I can use it with my PG 150 with it