MZ-7 problem?

IgorZ · 03-08-2017, 01:57 PM

I put new batteries in my MZ-7 back in the summer, and ran a couple of rolls of film through it. Then the batteries died, which I thought was odd, as I remember them lasting longer even when I used autofocus lenses. Now I just use manual focus. I thought maybe the batteries were bad. Now I take the lens off and the mirror is up. What is up with that? Is that what the famous stripped plastic gears syndrome looks like?

**grog85361** · 03-08-2017, 02:37 PM

In a word, yes. If the mirror is up, camera on or off, the plastic gear syndrome has bit you. I have had two MZ/ZX cameras do this to me.

IgorZ · 03-12-2017, 01:45 AM

Originally posted by grog85361

In a word, yes. If the mirror is up, camera on or off, the plastic gear syndrome has bit you. I have had two MZ/ZX cameras do this to me.

Hmm... I wonder if it's that or something else. Here is what happened, now that I think about it. I haven't used it for a while until last summer. I ran a couple of rolls of film through it until once when I was talking a photo the mirror didn't come down. I thought I'd look at it later and when I turned it on later the batteries were dead. I thought that was weird as I only had gone through a couple of rolls of film by then.

Fast forward to last Wednesday. I put in new batteries and the mirror comes down. I finish on old roll of film (1 shot) and load a new one. I take the camera out for some street photography and when I take the 11th photo the mirror doesn't come down. Basically, it sounded like a very long exposure shot. I tried to turn it off, but it wouldn't. I thought maybe it was too cold (- 17 Celsius), so I put it in the bag. When I took it out of the bag, the camera was off, which I thought was great. When I turned it on, the mirror was still up and the low battery sign was flashing. After 12 photos.

So I wonder if it is the stripped gears or something else. When I was taking the shot before the last one I remember being surprised that all of a sudden the camera changed exposure from something like 1/30 to 2 seconds. I was taking 3 photos in a row so I thought it was weird that the second one was metered longer than the other two. Then I thought it happened again when I took the last photo, just the mirror didn't come down. Could it be that it's an electric issue? Either way, does it make sense to fix it? That's my first camera and the only one I bought new, so I have an attachment to it...

Sluggo · 03-12-2017, 06:41 PM

Sorry, grog is right. What you describe is exactly how the MZ/ZX cameras behave when the gear on the mirror motor cracks. People sometimes assume it's an electrical problem because the battery drains so fast, but that's just an artifact of the motor getting stuck.

IgorZ · 03-12-2017, 07:47 PM

Originally posted by Sluggo

Sorry, grog is right. What you describe is exactly how the MZ/ZX cameras behave when the gear on the mirror motor cracks. People sometimes assume it's an electrical problem because the battery drains so fast, but that's just an artifact of the motor getting stuck.

Thanks guys. Oh well, I guess tike to close that chapter... Really appreciate your feedback!

**mlag** · 09-03-2022, 03:48 PM

Originally posted by Sluggo

Sorry, grog is right. What you describe is exactly how the MZ/ZX cameras behave when the gear on the mirror motor cracks. People sometimes assume it's an electrical problem because the battery drains so fast, but that's just an artifact of the motor getting stuck.

Just experienced this mirror up problem on my MZ-7.

Hence adding some extra info:
Symptoms:
- sounds like an extended exposure of many seconds, as mentioned higher.
- camera locks up (no reaction to any button, including on/off button)
- if you unmount lens, you can see the mirror is up
- batteries empty quickly, they even get warm, as some parts of camera. It seems the camera draws excessive power to keep mirror up frantically...

The last point is IMHO the reason why you should remove batteries as quick as possible. Overheating batteries and circuits can't be good.

Strange: the film advance picture number indicator keeps showing last number even when batteries removed, there seems to be some backup battery. Mirror keeps up, even after removing battery, might be because of backup battery.

Remedy, at least temporary:
Wait long enough without batteries in camera. Hour(s?), hard to say, didn’t wait next to camera.
Until LCDdisplay goes blank -no picture number- and mirror is down.
Re-insert batteries. Camera works again....

Just don’t know how many times I can repeat this trick... Time will tell.
But I have feeling that it is essential to remove batteries asap to avoid overheating and stressing the mechanism when it hangs...

**photogem** · 09-04-2022, 12:16 AM

As soon as the mirror is up and a short try to bring it down won't work, that's it with the MZ/ZX series.
It is a plastic part that is broken, difficult to repair, a working MZ/ZX7 is cheaper:
https://simonhawketts.co.uk/2016/04/16/mirror-return-motor-pentax-mz-5n/

As far as I know the Z/ PZ and SF/SFX versions (and the expensive MZ-S) of the Pentax AF filmcameras don't have that problem.
So an Z1/PZ1 or as SFX is a larger, heavier but better option.

03-08-2017, 01:57 PM	#1
IgorZ Veteran Member Join Date: Aug 2015 Location: Ottawa Posts: 1,735	MZ-7 problem? I put new batteries in my MZ-7 back in the summer, and ran a couple of rolls of film through it. Then the batteries died, which I thought was odd, as I remember them lasting longer even when I used autofocus lenses. Now I just use manual focus. I thought maybe the batteries were bad. Now I take the lens off and the mirror is up. What is up with that? Is that what the famous stripped plastic gears syndrome looks like?

09-03-2022, 03:48 PM	#6
mlag Loyal Site Supporter Join Date: Jul 2021 Location: Zuiderkempen - Grote Netewoud - Belgium Photos: Gallery \| Albums Posts: 1,399	MZ-7 mirror lockup - hanging camera - remove batteries longer time to reset Originally posted by Sluggo Sorry, grog is right. What you describe is exactly how the MZ/ZX cameras behave when the gear on the mirror motor cracks. People sometimes assume it's an electrical problem because the battery drains so fast, but that's just an artifact of the motor getting stuck. Just experienced this mirror up problem on my MZ-7. Hence adding some extra info: Symptoms: - sounds like an extended exposure of many seconds, as mentioned higher. - camera locks up (no reaction to any button, including on/off button) - if you unmount lens, you can see the mirror is up - batteries empty quickly, they even get warm, as some parts of camera. It seems the camera draws excessive power to keep mirror up frantically... The last point is IMHO the reason why you should remove batteries as quick as possible. Overheating batteries and circuits can't be good. Strange: the film advance picture number indicator keeps showing last number even when batteries removed, there seems to be some backup battery. Mirror keeps up, even after removing battery, might be because of backup battery. Remedy, at least temporary: Wait long enough without batteries in camera. Hour(s?), hard to say, didn’t wait next to camera. Until LCDdisplay goes blank -no picture number- and mirror is down. Re-insert batteries. Camera works again.... Just don’t know how many times I can repeat this trick... Time will tell. But I have feeling that it is essential to remove batteries asap to avoid overheating and stressing the mechanism when it hangs...

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03-08-2017, 02:37 PM	#2
grog85361 Site Supporter Join Date: Dec 2010 Location: Phoenix Arizona Photos: Gallery \| Albums Posts: 893	In a word, yes. If the mirror is up, camera on or off, the plastic gear syndrome has bit you. I have had two MZ/ZX cameras do this to me.

03-12-2017, 01:45 AM	#3
IgorZ Veteran Member Join Date: Aug 2015 Location: Ottawa Posts: 1,735 Original Poster	Originally posted by grog85361 In a word, yes. If the mirror is up, camera on or off, the plastic gear syndrome has bit you. I have had two MZ/ZX cameras do this to me. Hmm... I wonder if it's that or something else. Here is what happened, now that I think about it. I haven't used it for a while until last summer. I ran a couple of rolls of film through it until once when I was talking a photo the mirror didn't come down. I thought I'd look at it later and when I turned it on later the batteries were dead. I thought that was weird as I only had gone through a couple of rolls of film by then. Fast forward to last Wednesday. I put in new batteries and the mirror comes down. I finish on old roll of film (1 shot) and load a new one. I take the camera out for some street photography and when I take the 11th photo the mirror doesn't come down. Basically, it sounded like a very long exposure shot. I tried to turn it off, but it wouldn't. I thought maybe it was too cold (- 17 Celsius), so I put it in the bag. When I took it out of the bag, the camera was off, which I thought was great. When I turned it on, the mirror was still up and the low battery sign was flashing. After 12 photos. So I wonder if it is the stripped gears or something else. When I was taking the shot before the last one I remember being surprised that all of a sudden the camera changed exposure from something like 1/30 to 2 seconds. I was taking 3 photos in a row so I thought it was weird that the second one was metered longer than the other two. Then I thought it happened again when I took the last photo, just the mirror didn't come down. Could it be that it's an electric issue? Either way, does it make sense to fix it? That's my first camera and the only one I bought new, so I have an attachment to it...

03-12-2017, 06:41 PM	#4
Sluggo Veteran Member Join Date: Sep 2006 Location: Ames, Iowa Photos: Gallery \| Albums Posts: 774	Sorry, grog is right. What you describe is exactly how the MZ/ZX cameras behave when the gear on the mirror motor cracks. People sometimes assume it's an electrical problem because the battery drains so fast, but that's just an artifact of the motor getting stuck.

03-12-2017, 07:47 PM	#5
IgorZ Veteran Member Join Date: Aug 2015 Location: Ottawa Posts: 1,735 Original Poster	Originally posted by Sluggo Sorry, grog is right. What you describe is exactly how the MZ/ZX cameras behave when the gear on the mirror motor cracks. People sometimes assume it's an electrical problem because the battery drains so fast, but that's just an artifact of the motor getting stuck. Thanks guys. Oh well, I guess tike to close that chapter... Really appreciate your feedback!

09-04-2022, 12:16 AM	#7
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	As soon as the mirror is up and a short try to bring it down won't work, that's it with the MZ/ZX series. It is a plastic part that is broken, difficult to repair, a working MZ/ZX7 is cheaper: https://simonhawketts.co.uk/2016/04/16/mirror-return-motor-pentax-mz-5n/ As far as I know the Z/ PZ and SF/SFX versions (and the expensive MZ-S) of the Pentax AF filmcameras don't have that problem. So an Z1/PZ1 or as SFX is a larger, heavier but better option.