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Forum: Repairs and Warranty Service 01-22-2023, 02:24 AM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
Wow! I missed this post. Very interesting information!
This 645 has been in the back burner for a very long time, since it looks like there's a problem with the shutter button as well :/
That, and the 100+ cameras I'm going through 😄
I've been toying with the idea of using Nikon 7.2v batteries with a dc-dc converter, but there are several things to consider before that. We'll see.
J

---------- Post added 01-22-23 at 02:27 AM ----------



Hi there!
It has been a while, but as far as I remember there are a couple of screws on or underneath the side covers, and one or more at the top underneath the hotshoe. There may be another pair next to the eyepiece, but I may be confusing it with another camera.
Forum: Repairs and Warranty Service 01-14-2022, 09:39 AM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
Hi there!
Sorry for the delay in replying.
I'm afraid I can't help you that much :/
I wasn't able (and didn't have to) to remove the viewfinder to tighten the lens mount screws. I have a 2nd 645 that needs a bigger intervention, but I have not made that jump just yet.
Are you stuck with the viewfinder as well?
Forum: Repairs and Warranty Service 12-22-2020, 12:42 AM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
Will do! :)
Forum: Repairs and Warranty Service 12-12-2020, 08:29 PM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
No updates so far :/

Well... not on this at least. I have bought some very nice cameras :D

I'm in the middle of a thousand projects, and one of those is upgrading my 3d printer to handle better filaments. My goal is to make the battery holder (and a few other parts) in carbon fiber reinforced nylon or polycarbonate, but either one requires higher temperatures than what my printer can handle at this point.

I'll see if can shift a couple priorities around here ;)

Cheers!
Forum: Repairs and Warranty Service 08-17-2020, 09:10 AM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
Selling them may be interesting :)
But I'll need to really work out the battery contacts before I can do so. As of now I'm using some plastic foam and thin metal strips, but replacing the batteries is a pain in the neck :/
Forum: Repairs and Warranty Service 12-11-2019, 11:10 PM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
I printed it at home, and the materials probably cost just a few bucks (not counting the hours doing the reverse engineering, that is).

The thing is not yet fully "cooked", though. My solution to the battery contacts (metal stripes held by double-sided tape) needs to be improved, but as a proof of concept it works just fine.

I just need to go back and correct tolerances :)

I'm also looking at using a different material (probably polycarbonate). The PLA I used may warp if exposed to heat.
Forum: Repairs and Warranty Service 12-09-2019, 08:12 PM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
Hi! Thank you for the offer, but as Niceshot says it seems to be very different. The 645n has two rows of 3 batteries, while the original one has them in 2 triangular arrays.

The good news is that I already printed one and it's fine. I had to sand it like crazy because I forgot to include tolerances 🙄, but at least I can power the camera 😬.

Now I'm looking for a lens for a fair price, but I'll wait until I find a good deal. In the meantime I'm trying to design an adapter for a Mamiya Press lens. The short distance between the lens and the flange is proving difficult 😕
Forum: Repairs and Warranty Service 11-19-2019, 07:16 PM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
I got one already :)
Minus the battery holder :(
...and it happened to be attached to another Pentax 645, with slightly different issues O.o

I'm reverse-engineering the battery holder right now. I expect to be 3D printing one in the very near future.

EDIT: if any of you can take a head-on picture of the bottom of the battery holder it would be great. The latch needs to be in a very specific place, and it's easier to get the data from a decent picture :)

J
Forum: Repairs and Warranty Service 10-14-2019, 07:48 PM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
Alright... I hate when this happens, but I'm somewhat glad it did: I have to answer my own question - at least partially.

I still don't know how far the "diopter ring" (the rubber-covered ring around the eyepiece) should turn in either direction, but at the end of the day it didn't matter. It wasn't necessary to remove the eyepiece at all.
The only thing preventing the top cover from moving far enough to be able to tighten the mount screws was one of the metal side covers. Tolerances are very high, and the increased resistance was enough to make me doubt myself-and the service manual.

In any case: the deed is done. Now I just need a battery grip - and a lens :)
Forum: Visitors' Center 10-13-2019, 08:46 PM  
occupation
Posted By jay_2791
Replies: 54
Views: 4,857
Engineer in the automotive sector, but in my previous life I designed a couple of cameras for a small startup.
I enjoy taking pictures and have received some tips for doing so, but it remains a hobby.

But I'm seriously addicted to collecting cameras. Too many of them :D
Forum: Repairs and Warranty Service 10-13-2019, 08:40 PM  
Pentax 645 - Loose lens mount - can't remove top cover to fix it
Posted By jay_2791
Replies: 19
Views: 4,586
Hello people,

I just added a Pentax 645 (original, not N) to my camera collection, and I need some help with it :)

I bought the camera from one of the traditional retailers for a small price, due to it being sold "as-is". The camera seems to be in very decent shape, with one exception: the lens mount is loose (it's also missing the grip, but that's another story). Before "investing" any more money on this setup, I want to make sure everything is working fine, and this implies fixing the lens mount.

I bought the 645's service manual (and then found it free somewhere else :mad:), and managed to remove the bottom cover and tighten the *very* loose two bottom screws. Now I'm trying to get to the top two screws, but I can't make any sense of the instructions. Specifically, the instructions tell to remove three "A502" screws. Two are obvious, but there seems to be another one below the eyepiece (see image). If that's the case, the eyepiece (and the diopter adjusting ring) need to be removed. But:

I managed to remove the threaded tube containing the rear element of the eyepiece, but the diopter adjusting ring is *very* stiff, and I don't even know if it should come out by turning it or . The ring was very stiff to begin with, but I have no idea how much -or how easily- it should turn.

I wonder if anyone around here has gutted one of these before and knows (and is willing to share) how to get the diopter adjusting ring and/or the top out - in a reversible manner :lol:

Thanks!

JR
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