Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-29-2018, 12:02 PM - 1 Like   #16
Moderator
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 10,510
QuoteOriginally posted by felixkh Quote
I am sorry but I not longer have that part. Threw it away 2 days after the camera came back.
Alas, a positive ID of the gear might have helped to clear up if the S came with the metal gear from the factory. Do you recall where the gear was melted? Overall? Teeth? Shaft hole?

09-30-2018, 05:21 AM   #17
Site Supporter
Site Supporter




Join Date: Nov 2008
Location: Singapore
Photos: Gallery
Posts: 1,201
Original Poster
QuoteOriginally posted by Not a Number Quote
Alas, a positive ID of the gear might have helped to clear up if the S came with the metal gear from the factory. Do you recall where the gear was melted? Overall? Teeth? Shaft hole?
Sorry, but they did not indicate where the part was actually located.My understanding from the gurus in Singapore is the gear that rotates for the mirror motor to move the mirror up/down. I have the original spare and the gear is plastic. I bought it in 2-13 expecting someone in Singapore to be able to repair but alas none could do so.
09-30-2018, 08:58 AM   #18
Moderator
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 10,510
QuoteOriginally posted by felixkh Quote
Sorry, but they did not indicate where the part was actually located.My understanding from the gurus in Singapore is the gear that rotates for the mirror motor to move the mirror up/down. I have the original spare and the gear is plastic. I bought it in 2-13 expecting someone in Singapore to be able to repair but alas none could do so.
What area or section of the returned gear was melted? The entire gear? Just around the shaft? The teeth?

The entire gear melting might indicate material failure. Melting around the shaft or teeth could indicate either the motor seizing (if it was the motor gear) or the rest of the train seizing up. The motor gear would be identifiable by the number of teeth, diameter and width.

Since they only replaced the one gear and not the motor or two or more gears I would suspect the gear spinning on the motor shaft with enough friction to melt the gear but not enough to spin the gear and melt or break the teeth.
09-30-2018, 09:56 PM   #19
Site Supporter
Site Supporter




Join Date: Nov 2008
Location: Singapore
Photos: Gallery
Posts: 1,201
Original Poster
QuoteOriginally posted by Not a Number Quote
What area or section of the returned gear was melted? The entire gear? Just around the shaft? The teeth?

The entire gear melting might indicate material failure. Melting around the shaft or teeth could indicate either the motor seizing (if it was the motor gear) or the rest of the train seizing up. The motor gear would be identifiable by the number of teeth, diameter and width.

Since they only replaced the one gear and not the motor or two or more gears I would suspect the gear spinning on the motor shaft with enough friction to melt the gear but not enough to spin the gear and melt or break the teeth.
It looked like the little black plastic gear that moves another gear on the shift of the mirror motor.I don't really know which is the part as there was no note about where and what was replaced.

05-01-2019, 03:35 PM - 3 Likes   #20
Veteran Member




Join Date: Aug 2010
Location: Winnipeg MB
Photos: Gallery
Posts: 350
Plastic Mirror Motor Gear

I am one of the persons who replaced mirror motors in MZ series of cameras. Since the plastic gear is press fit to the motor shaft, the internal stress eventually would split the gear so the motor would keep on rotating but the gear would not turn resulting in permanent mirror lock. If you have replacement motor with brass gear, it is possible to DIY. I've written done detailed procedure some where in the Forum. If you have the 13-tooth gear made, the center hole has to be drilled just a shade smaller than the motor shaft. Put the metal gear in boiling water, dip motor shaft in ice water, then press the gear into the shaft.
The company changed name to Pentax Corporation in 2002. If your camera is stamped "PENTAX CORPORATION Made in Japan", you probably have metal gear on mirror motor shaft. My post-2002 MZ-6 has brass gear. The other MZ-6, stamped "ASAHI OPT. CO. LTD." has black plastic gear.
Attached Images
View Picture EXIF
X10  Photo 

Last edited by violini; 05-01-2019 at 03:44 PM.
05-01-2019, 04:02 PM   #21
Otis Memorial Pentaxian
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 42,007
QuoteOriginally posted by violini Quote
I am one of the persons who replaced mirror motors in MZ series of cameras. Since the plastic gear is press fit to the motor shaft, the internal stress eventually would split the gear so the motor would keep on rotating but the gear would not turn resulting in permanent mirror lock. If you have replacement motor with brass gear, it is possible to DIY. I've written done detailed procedure some where in the Forum. If you have the 13-tooth gear made, the center hole has to be drilled just a shade smaller than the motor shaft. Put the metal gear in boiling water, dip motor shaft in ice water, then press the gear into the shaft.
The company changed name to Pentax Corporation in 2002. If your camera is stamped "PENTAX CORPORATION Made in Japan", you probably have metal gear on mirror motor shaft. My post-2002 MZ-6 has brass gear. The other MZ-6, stamped "ASAHI OPT. CO. LTD." has black plastic gear.
So perhaps you know; does the MZ-S (released 2001) have the plastic gear? This question comes up with some regularity with no firm answers. Even on this thread, the OP was not certain which gear melted.


Steve
05-01-2019, 06:40 PM - 4 Likes   #22
Veteran Member




Join Date: Aug 2010
Location: Winnipeg MB
Photos: Gallery
Posts: 350
Yes, same as MZ-6 released in 2001, has black plastic gear as shown in the above photo. These motors are taken out from failed MZ cameras. The plastic gear is not melted, just split at the center hole and can no longer hold on to the motor shaft. I have not seen any melted plastic gear but it is possible. If the gear splits in the middle of a cycle, the motor will continue running at 15K rpm if the camera is not immediately turned off, the friction between motor shaft and the pinion would generate sufficient heat to melt the plastic. Removing the bottom cover of the camera, you can easily see the mirror motor and the gear. If it is stamped: "PENTAX CORPORATION Made in Japan", most likely you'll have brass gear. The other two motors (one for focusing, another for transport film) are equipped with brass gears. I don't know why Pentax engineers would choose plastic gear for the mirror motor. The gear is 3.75mm in diameter; the center core area is very thin and would not be adequate to take the torque for flipping the mirror. I've opened two MZ-60, both have brass gear and stamped "PENTAX CORPORATION Assembled in Philippine". So when you are in the market for a MZ camera, look for the marking shown in the photo below. If it is stamped "ASAHI OPT. CO. LTD.", you will have to remove the bottom cover to see if the mirror motor gear has been replaced or not. If it is not, don't buy it.

Attached Images
 
View Picture EXIF
X10  Photo 

Last edited by violini; 05-10-2019 at 07:02 PM.
05-01-2019, 07:30 PM - 1 Like   #23
Otis Memorial Pentaxian
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 42,007
QuoteOriginally posted by violini Quote
Yes, same as MZ-6 released in 2001, has black plastic gear as shown in the above photo.
OK...If you have taken plastic-geared motors out of an MZ-S, then that seals it. The reason I ask is that there has been speculation for years on this site that due to the MZ-S' flagship position and ground-up new design (shares little in common with its cousins), its robust metal build might have included ruggedized film transport and mirror drive components.


Steve
05-10-2019, 03:39 AM   #24
Pentaxian
womble's Avatar

Join Date: Apr 2010
Location: Hertfordshire
Photos: Gallery
Posts: 4,324
QuoteOriginally posted by leekil Quote
They are not all that complicated.
Perhaps I should have said "mechanical". I spend my life using high-tech gear so it is nice, for fun, to use something (almost) completely mechanical and manual, like my 1964 Spottie or one of my 1950s folders. At some point I should be getting a nice medium format pinhole camera to play with... If I need the convenience of automation I use my K-3.

---------- Post added 05-10-19 at 11:44 AM ----------

QuoteOriginally posted by violini Quote
Yes, same as MZ-6 released in 2001, has black plastic gear as shown in the above photo...
Perhaps one of the most useful postings ever. Thank you for the definitive answer.... at last!
11-22-2019, 08:40 AM   #25
New Member




Join Date: Nov 2019
Posts: 6
I was wondering/hoping that possibly the change to a metal gear took place when the production line moved to the Philippines. I’ve just picked up a working MZ5n branded Asahi Opt Co but made in the Philippines rather than in Japan. It would seem more logical to me to make the change when setting up a new production line rather than a name change, but if I’m right I’ll never know!
QuoteOriginally posted by violini Quote
Yes, same as MZ-6 released in 2001, has black plastic gear as shown in the above photo. These motors are taken out from failed MZ cameras. The plastic gear is not melted, just split at the center hole and can no longer hold on to the motor shaft. I have not seen any melted plastic gear but it is possible. If the gear splits in the middle of a cycle, the motor will continue running at 15K rpm if the camera is not immediately turned off, the friction between motor shaft and the pinion would generate sufficient heat to melt the plastic. Removing the bottom cover of the camera, you can easily see the mirror motor and the gear. If it is stamped: "PENTAX CORPORATION Made in Japan", most likely you'll have brass gear. The other two motors (one for focusing, another for transport film) are equipped with brass gears. I don't know why Pentax engineers would choose plastic gear for the mirror motor. The gear is 3.75mm in diameter; the center core area is very thin and would not be adequate to take the torque for flipping the mirror. I've opened two MZ-60, both have brass gear and stamped "PENTAX CORPORATION Assembled in Philippine". So when you are in the market for a MZ camera, look for the marking shown in the photo below. If it is stamped "ASAHI OPT. CO. LTD.", you will have to remove the bottom cover to see if the mirror motor gear has been replaced or not. If it is not, don't buy it.
06-13-2022, 07:40 AM - 1 Like   #26
Junior Member
estost's Avatar

Join Date: May 2016
Photos: Gallery
Posts: 33
QuoteOriginally posted by Not a Number Quote
This company was discussed previously in this thread:

Lens Repair Co. run by Retired Pentax Engineers - PentaxForums.com

Note: The mirror motor gear problem is usually that the plastic gear on the motor cracks. The replacement motors had metal gears on them, and perhaps some of the later production cameras came equipped with the metal gear. There is a website (in Poland as I recall) that sells a compatible gear that you can get in brass. However, you need to either change the gear yourself or find a technician that will do it for you.

kkpmo - Zahnrad / Trieb M0.25 / 13 Zähne

You need to change the 1.5mm and the width to 2.0 and material to brass - although you could leave it as plastic that might break again in time. If you searched around you could probably find another source for the same size gear.
Really happy about this quality thread. Even the links are all still alive. My MZ-S is running fine, but since it is the older Asahi model with S/N 483nnnnn I thought I'd rather be on the safe side and order one of those gear wheels from Poland. Your sentence about the specifications unfortunately may have some words missing, just to make sure: Do you mean the hole diameter should be set to 1.5 and the gear width to 2.0 or do you mean both values should read 2.0? This way the gear would be ready for pressfitting the way violini describes in comment #20 or would it need some further manual tinkering? Thanks for a swift reply even after more than three years
06-13-2022, 08:11 AM - 1 Like   #27
Pentaxian
Jonathan Mac's Avatar

Join Date: Apr 2009
Location: Madrid, Spain
Posts: 10,852
QuoteOriginally posted by yucafrita Quote
Are we sure that this is the same issue like with the other MZ-series cameras? I find it puzzling that there are basically no reports on that with the MZ-S. Or is it just because few MZ-S were sold? Hope mine doesnt fail.
I was surprised when I first came across a report of this problem in the S but it does seem that early versions did have the problem. I had thought it was limited to the cheaper cameras but no, Pentax even cheaped out on the top model.
06-14-2022, 12:35 PM   #28
Moderator
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 10,510
QuoteOriginally posted by estost Quote
Really happy about this quality thread. Even the links are all still alive. My MZ-S is running fine, but since it is the older Asahi model with S/N 483nnnnn I thought I'd rather be on the safe side and order one of those gear wheels from Poland. Your sentence about the specifications unfortunately may have some words missing, just to make sure: Do you mean the hole diameter should be set to 1.5 and the gear width to 2.0 or do you mean both values should read 2.0? This way the gear would be ready for pressfitting the way violini describes in comment #20 or would it need some further manual tinkering? Thanks for a swift reply even after more than three years
The hole diameter should be 1.5mm. The thickness of the gear should be 2mm.
06-15-2022, 10:25 PM   #29
Veteran Member
Eyewanders's Avatar

Join Date: Jan 2008
Location: Land of the Salish Sea
Photos: Gallery | Albums
Posts: 3,343
I have two or three of these gears that I ordered (for MZ-S and MZ-3, just in case) years ago now in an envelope.... somewhere.... hopefully well-labeled. I should probably sort that out.

---------- Post added 06-15-22 at 10:26 PM ----------

QuoteOriginally posted by Jonathan Mac Quote
I was surprised when I first came across a report of this problem in the S but it does seem that early versions did have the problem. I had thought it was limited to the cheaper cameras but no, Pentax even cheaped out on the top model.
Yeah. I really had my money on it being metal in the S as well. :womp womp:
06-16-2022, 06:17 AM   #30
Pentaxian
Jonathan Mac's Avatar

Join Date: Apr 2009
Location: Madrid, Spain
Posts: 10,852
QuoteOriginally posted by Eyewanders Quote
I have two or three of these gears that I ordered (for MZ-S and MZ-3, just in case) years ago now in an envelope.... somewhere.... hopefully well-labeled. I should probably sort that out.

---------- Post added 06-15-22 at 10:26 PM ----------



Yeah. I really had my money on it being metal in the S as well. :womp womp:
Yep. What I haven't heard though is any indication of Pentax changing to using the metal gear in the other MZ series cameras once they became aware of the problem. So it seems the S was the only one they were willing to spend the extra $0.01 on to make much more reliable.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
bottom, camera, cameras, email, film, gear, mirror, motor, mz, mz-s, old-new mz-s, pentax, photo, plastic, slr
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Returning to photography after years. Looking for advice. MrTiburon Troubleshooting and Beginner Help 25 04-30-2017 09:54 AM
Returning to Pentax after 30+ years! ldgreen Welcomes and Introductions 2 07-06-2012 04:03 AM
The difference between MZ-5, MZ-7 and MZ-10? Raffwal Film SLRs and Compact Film Cameras 7 02-11-2012 05:03 PM
Wanted - Acquired: any of Pentax MZ-S, Z-1P, Z-1,MZ-3, MZ-5N, MZ-5, MZ-6 tianyawoya Sold Items 1 07-10-2010 08:13 AM
Hands-On Comparison MZ-5n vs MZ-L(6) vs MZ-S k100d Film SLRs and Compact Film Cameras 37 02-01-2009 11:25 PM



All times are GMT -7. The time now is 05:03 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top