Petri 7s Aperture blade cleaning

[ted_tofield]

[FONT=Arial, Helvetica]Hello chaps,

I'm hoping someone can help me, I have sticking aperture blades on my beloved Petri 7s and have decided to tackle the job myself.

I'm fully armed with tiny screwdrivers, cotton buds and Ronsonol and have got as far as taking off everything in front of the shutter mechanism....BUT....I'm now stuck as I can't work out how to remove this to access the next layer back (which should be the aperture section)

I've got the instruction manual and the service manual, however the repair manual only has exploded diagrams and not descriptions of techniques...

Can anybody help me please?[/FONT]

 

[FallisPhoto]

[FONT=Arial, Helvetica]Hello chaps, [/FONT]

[FONT=Arial, Helvetica]I'm hoping someone can help me, I have sticking aperture blades on my beloved Petri 7s and have decided to tackle the job myself. [/FONT]

[FONT=Arial, Helvetica]I'm fully armed with tiny screwdrivers, cotton buds and Ronsonol and have got as far as taking off everything in front of the shutter mechanism....BUT....I'm now stuck as I can't work out how to remove this to access the next layer back (which should be the aperture section) [/FONT]

[FONT=Arial, Helvetica]I've got the instruction manual and the service manual, however the repair manual only has exploded diagrams and not descriptions of techniques... [/FONT]

[FONT=Arial, Helvetica]Can anybody help me please?[/FONT]

First off, I don't have a Petri 7S, so I can't give you any firsthand advice. However, the service manual should have disassembly instructions: http://www.tradebit.com/filedetail.php/831492-petri-7s-camera-service-manual

If not, then you'll get a lot better advice on the Classic Camera Repair Forum than you are likely to find here: http://www.kyphoto.com/cgi-bin/forum/discus.cgi

Next thing to try is this website: http://pheugo.com/cameras/index.php At the bottom of the page are links to illustrated pages on cleaning many types of shutters. You do have to know what kind of shutter your camera has though.

If all else fails, then if you can just get the lens elements out of it, you can clean the shutter blades with lighter fluid and stop them from sticking. You wet one end of a Q-tip, sopping wet, and swab them down, work the blades a few times and mop up the wet lighter fluid (and dissolved crud) with the dry end. Throw the Q-tip away and repeat. You'll have to do this about 50 times (no joke), but it works. This is how about 90% of the people here get their cameras working.

Lastly, it might just be that you don't have an essential tool used for opening shutters. I noticed that you mentioned jeweller's screwdrivers, but you did not mention a lens wrench: http://cgi.ebay.com/A-NEW-SPANNER-W...ryZ30038QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

[btgc]

There on kyphoto is service manual for Petri 7s for free, would be interesting to know if paid version is different from free one.

Full disassembly and cleaning gives guarantee for couple of next (or decades) years. Also opens chance for having nice parts camera, for first time.

 

[FallisPhoto]

There on kyphoto is service manual for Petri 7s for free, would be interesting to know if paid version is different from free one.

Full disassembly and cleaning gives guarantee for couple of next (or decades) years. Also opens chance for having nice parts camera, for first time.

Full disassembly is probably not a good idea, unless he has done this before. If it is his first time, I think he should start with a much simpler camera -- maybe an Argus C-3.

 

[btgc]

Full disassembly is probably not a good idea, unless he has done this before. If it is his first time, I think he should start with a much simpler camera -- maybe an Argus C-3.

Heartfully agree! And cotton swab technique is adequate if dirt is not too much.
Only thing I noticed - fast feedback of fast route makes camera usable, and if cleaning is not completed, shutter freezes up after some time. Especially when weather gets wet.
So your mentioned 50 cycles is realistic milestone.

 

[FallisPhoto]

Heartfully agree! And cotton swab technique is adequate if dirt is not too much.
Only thing I noticed - fast feedback of fast route makes camera usable, and if cleaning is not completed, shutter freezes up after some time. Especially when weather gets wet.
So your mentioned 50 cycles is realistic milestone.

If you don't go through at least 50 cycles, then dirty grease spreads from other parts of the shutter through the wet naptha and redeposits on the shutter blades. It takes that many times to have a chance of dissolving and removing enough crud to make a difference. Of course, disassembly and hand cleaning is the best method. Sadly, many people are not competent to do this. For them, it is better to use the cotton swab method, They will at least have a working camera instead of a pile of parts that they can't reassemble then.

 

[btgc]

Of course, disassembly and hand cleaning is the best method.

OK, cleaning teeth with brush and string gives much better results than just rinsing with water.

Interesting - when this cameras were new, how many years of impeccable work owners enjoyed before taking them for shutter cleaning - I mean disassembly'n'cleaning - if ever? Sure, it depended on environment where cameras were used...but on average? How much owner had to pay for this kind of servicing (compared to price of new camera) - back then, not this days?

 

[FallisPhoto]

Interesting - when this cameras were new, how many years of impeccable work owners enjoyed before taking them for shutter cleaning - I mean disassembly'n'cleaning - if ever? Sure, it depended on environment where cameras were used...but on average? How much owner had to pay for this kind of servicing (compared to price of new camera) - back then, not this days?

A schedule of regular routine maintenance should include a CLA (clean, lubricate and adjust) at least every 10 years and replace normal polycarbonate foam light seals at the same time (Neoprene or Interslice light seals can easily last 20 years). That is if the camera gets minimal use. If it gets heavy use, then it should be serviced at least every 5 years.

Unfortunately, only pros seem to service their cameras at all. I've bought many vintage cameras on ebay, and in every one of them that used foam light seals, the foam had deteriorated far beyond the stage where it needed to be replaced.

In vintage cameras I have only one time seen evidence that the original owner had replaced the seals. Since this is usually done at the time the camera is serviced, I think that only this one, out of over 100 cameras, was cleaned back in the day.

 

[ted_tofield]

Thanks for the advice guys, given that this is my first dismantlement I'm not prepared to take the whole thing apart into tiny cogs and springs! I'll be swabbing and gently cleaning first and I'll return here to let you know how I got on! 🙂

 

[FallisPhoto]

Thanks for the advice guys, given that this is my first dismantlement I'm not prepared to take the whole thing apart into tiny cogs and springs! I'll be swabbing and gently cleaning first and I'll return here to let you know how I got on! 🙂

With the front of the shutter, this is as far as you need to go:

Once you have reached this stage, just squirt some naptha (lighter fluid) in there and start scrubbing with an artist's brush. Then flush the loosened crud out with more naptha.

 

[ted_tofield]

Yup, that's where i'm at.....thx!

 

[btgc]

Oh, good idea on brush! I've always wanted to take more crud out by reaching areas inside, so I gently pushed inside small strips of lens cleaning paper (folded several times to have some strength).

Will try brush on my Lynx 5000, while shutter is opened [for slow speed escapement washing]

Ted, get back with your results!

 

[ted_tofield]

Hmmm... the news is not good. Whilst the Ronsonol cleaning process went well and everything now moves very smoothly, one of the aperture blades seems to have jumped off it's guide and doesn't move with the others. (hopefully not broken off...)

If I could get to it I'm confident it could be hooked back on. Unfortunately the shutter mechanism is in the way and is in no way easy to remove. The service manual (well...exploded diagram) suggests the whole lot comes away as a single piece... but I wouldn't bet my life on it.

Any advice?

I could send it off for a service but don't want to splash out cash if I don't have to... (a shame as I inherited the camera from my dear departed grandparents)

 

[btgc]

Haven't taken 7s' shutter apart, so can't comment on how easy or not it reacts to repair efforts.

It can be done, with [some or a lot of] efforts. If it's dear memory from grandparents, maybe keep it as is, at least for a while. Get another 7s, use it or take apart to learn if sample isn't particularly good? Later you can return to this one to fix it. Just look for same model/lens (2.8 or 1.9) - to have spare parts in case you'll need.

 

[ted_tofield]

Hmmm. unless I can get more explicit instructions I think I'll heed your advice and leave well alone for the meantime...unless anyone else has any bright ideas?

 

[FallisPhoto]

Hmmm. unless I can get more explicit instructions I think I'll heed your advice and leave well alone for the meantime...unless anyone else has any bright ideas?

I don't know if this will help, because I am not sure what kind of shutter you have, but I have a website bookmarked that has repair notes on close to 20 different shutters. Odds are good that it is in here: http://pheugo.com/cameras/index.php

 

[FallisPhoto]

Oh, good idea on brush! I've always wanted to take more crud out by reaching areas inside, so I gently pushed inside small strips of lens cleaning paper (folded several times to have some strength).

Will try brush on my Lynx 5000, while shutter is opened [for slow speed escapement washing]

Ted, get back with your results!

I used to do that too, but one day I was in a hobby shop, saw some inexpensive brushes and thought they would be really good for cleaning shutters. The really cheap plastic ones they sell at hobby shops are best. They have very fine plastic bristles, will stand up to naptha without the glue that holds the bristles in dissolving, and they don't shed. When you are done, they are cheap enough to just throw away. I use them for all kinds of stuff (applying contact cement, epoxy paint, and so on) that would ruin a brush, because they are disposable.

 

[btgc]

I don't know if this will help, because I am not sure what kind of shutter you have, but I have a website bookmarked that has repair notes on close to 20 different shutters. Odds are good that it is in here: http://pheugo.com/cameras/index.php

This is useful site, and finally Ted you just have to make a step...once you go, step follows step. It's possible that you ruin camera, that's why I suggest getting another 7s in $5-10 range.

On lens barrel is written Petri MVE - I'm not sure if they used proprietary shutter design instead of generic one for inexpensive camera. Could it be Citizen MVE ? I weren't able to find confirmation, at least speed range matches that on 7s.

Anyway, it doesn't depends much - I haven't dealt with Citizen, though Copal leaf shutter varieties are pretty similar each to other and suffer from same problems - mostly, deposited crud and dried grease.

P.S. Fallis, thanks for "plastic brush" tip - recently I bought squirrel brush for lenses so I could forget requirement to withstand naphtha :bang:

 

[ted_tofield]

Excellent work lads!

I've just taken a quick look and a couple on there look very similar... I'll check it out when I have more time over the weekend.

thanks again!

 

[btgc]

Yeah, Ted, do yourself a nice weekend 😉 just watch your sight if it's not top notch - easy to fall into lust "oh, seems that I'll fix it in next five minutes" - this job puts a lot of strain on eyes.

FallisPhoto - "brush method" is excellent! Allows to reach inner space and much much easier to clean between leafs, much stronger and faster than paper strips.
Revisited Lynx 5000 while it's opened and 72E - little one became lazy again after last roll.

I think this is good resource, too http://shutter-cla.blogspot.com/