[builttospill]

I have two MZ-S bodies (Asahi) which don't have any issues with the gear, and one MZ-3 body where I've removed the split plastic gear in two pieces. I have a brass gear ready but haven't had the time to fix it yet.

[Bonner04]

I have two MZ-S bodies (Asahi) which don't have any issues with the gear, and one MZ-3 body where I've removed the split plastic gear in two pieces. I have a brass gear ready but haven't had the time to fix it yet.

I miss my MZ-3...

[Eyewanders]

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.

I'm replying here (rather than in the other, more recent MZ-S thread) at the risk of being tedious regarding this issue, but my point is there is still not substantive proof that the MZ-S falls into this issue category. My fear is, as I said, going down the "most repeated thing is true" that can sometimes happen here on the forums.

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.

Without getting too granular over the thread history (the many) covering this topic, this post is key. I could be mistaken, absolutely, but it seems there's some conflation going on here, between Felixkh's specific case, and the problem gears found in the other MZ camera types that you have worked on. As I have understood it, the cameras that you (Violini) have personally repaired since 2010 have all be earlier MZ models, e.g. camera other than the MZ-S. Is it accurate that none of the motors shown in your photo are units that were removed from an MZ-S camera?

Going further, the line-in-the-sand as it were used to differentiate "problem" cameras by identifying them via the production stamp and serial numbers seems reasonable certainly, but it isn't definitive. Again, I fear conflation. You also mention removing the bottom plate to inspect suspect cameras. Can you show this specifically on the MZ-S in your photo? I ask because another forum member has reported the motor location being (not surprisingly) different on the MZ-S and, in contrast with the other MZ/ZX models, the gear in question was not visible for inspection by just removing the bottom plate. I would love to confirm with my own early model (which is stamped "Asahi Co. serial 4x...) but I found the teardown is much more complicated than my MZ-3 and without having a repair manual or prior experience with these personally, it seems that there is weather sealing involved and perhaps the grip and front covers hide further screw points for release of the bottom plate. Granted, I stopped well short into process because I'm not willing to accidentally sacrifice my working unit.

If you could provide just some brief partial teardown notes for removal of the bottom cap, and a photo from that vantage point pointing to the gear location, it would be ENDLESSLY helpful in putting the ambiguity in this issue to bed completely. Thanks in advance. Many, many thanks in advance.

---------- Post added 06-29-22 at 09:07 AM ----------

For clarity in case any want it, these are the most pertinent related threads:
MZ5n mirror blocked, service manual? - Page 8 - PentaxForums.com

The real truth on the MZ-S mirror motor gear? - Page 4 - PentaxForums.com

My old-New MZ-S After Returning From Repair - PentaxForums.com

Has your MZ-6 / MZ-L / ZX-L mirror gear failed? - PentaxForums.com

Looking to buy an MZ-S - Common issues? - PentaxForums.com



---------- Post added 06-29-22 at 09:21 AM ----------

Note:
Violini has not posted to the forum since 2019, around the time of this thread. I hope that he may come back around but it's my understanding that he has never owned an MZ-S, so I suspect the photo showing the serial stamp he included was just illustrative and taken from another source. But I REALLY HOPE that I am completely incorrect.

[Jonathan Mac]

I'm replying here (rather than in the other, more recent MZ-S thread) at the risk of being tedious regarding this issue, but my point is there is still not substantive proof that the MZ-S falls into this issue category. My fear is, as I said, going down the "most repeated thing is true" that can sometimes happen here on the forums.

Yes, I think you're right but overall it's enough to steer me away from the MZ-S when taken with the price and the fact that it's inferior in some ways to the Z-1.

If I ever see one for a decent price I'd still like to try it but for what they normally go for I wouldn't risk it.

[Eyewanders]

Yes, I think you're right but overall it's enough to steer me away from the MZ-S when taken with the price and the fact that it's inferior in some ways to the Z-1.

If I ever see one for a decent price I'd still like to try it but for what they normally go for I wouldn't risk it.

That's kinda why I brought it up again... These posts scare people away. Frankly I've heard of just as many Z1p/PZ-1p with mirror issues (very few but about the same number) and these days, for a good working copy (non "parts-only") they seem to be around same asking price as the MZ-S. The regular Z1 is slightly less expensive, but not by much now.

I think reality is that the Zs are older, but all of these, Z1 and MZ cameras alike, even those with replacement motors & brass gears still have a host of other plastic parts within the gear train, drive belts that can wear, seals etc. Point being.. there's reason to be scared of any of them but I don't think the MZ-S deserves any additional fear.

[gofour3]

I would love to confirm with my own early model (which is stamped "Asahi Co. serial 4x...)

If it is stamped: "PENTAX CORPORATION Made in Japan", most likely you'll have brass gear

Yeah the rule of thumb you hear is that the MZ cameras with "Asahi Opt. Co. Ltd. Made in Japan" and a serial number of 4xxxxxx have the plastic gear, but the "PENTAX CORPORATION Made in Japan" and a serial number of 5xxxxxxx have brass.

However my MZ-S has a s/n of 5xxxxxxx, but has "Asahi Opt. Co. Ltd. Made in Japan"???

So who knows for sure with the MZ-S. I'm betting the MZ-S camera is different and all have the brass gear. The dodgy plastic gear MZ cameras were released in 1996/97, the MZ-S did not come out till 2001. By then Pentax had already replaced the plastic gears on these older bodies with brass, so it's unlikely Pentax would have used plastic gears in any MZ-S in 2001.

My advice is just buy one, as the MZ-S are great cameras and fun to use. I like the aperture/shutter speed imprinting on the film edge, great for testing new (to me) lenses. (F Series or newer for imprinting)

Phil.

[Eyewanders]

Yeah the rule of thumb you hear is that the MZ cameras with "Asahi Opt. Co. Ltd. Made in Japan" and a serial number of 4xxxxxx have the plastic gear, but the "PENTAX CORPORATION Made in Japan" and a serial number of 5xxxxxxx have brass.

However my MZ-S has a s/n of 5xxxxxxx, but has "Asahi Opt. Co. Ltd. Made in Japan"???

So who knows for sure with the MZ-S. I'm betting the MZ-S camera is different and all have the brass gear. The dodgy plastic gear MZ cameras were released in 1996/97, the MZ-S did not come out till 2001. By then Pentax had already replaced the plastic gears on these older bodies with brass, so it's unlikely Pentax would have used plastic gears in any MZ-S in 2001.

My advice is just buy one, as the MZ-S are great cameras and fun to use. I like the aperture/shutter speed imprinting on the film edge, great for testing new (to me) lenses. (F Series or newer for imprinting)

Phil.

Exactly that. In this specific case, from everything I've been able to gather, that thumb-rule is derived specifically from the MZ-60 which was released earlier that year. The sticking point for me is that the change in name badging on those cameras allegedly occurred in 2002, the second year of MZ-S production. But the MZ-S was produced until 2006 so one would think that the vast majority of cameras in the wild should be badged "PENTAX Corporation", however the opposite is true; those with the Asahi badging are much more common, and the Pentax Corp versions seem to be quite rare in comparison. So one would think there'd be many many more failures reported. There aren't.

But yeah - I agree with you to simply not worry on it as a large issue, at least nowhere in the vicinity of the very warranted worry over the likes of MZ-5n or MZ-7 etc.
If mine ever fails, I'll rip it open and see but until then I'll carry on using.

[Sydley]

Ok I went there. It’s in Japanese and only translates the initial text. The repair request sheet is all Japanese. I forwarded the pdf from my iPhone to my pc as an email. I’ll see if it can sort it out from there.