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Ollie
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 14, 2005 - 05:18 pm: | 
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Dear all,
I have a Canon A-1 and all the foam seals have gone, including the piece which buffers the mirror as it flips up. Some bits of foam got onto my focusing screen, so I tried to lift them off with a very soft paintbrush. However this made it worse smearing a couple of bits all over it and speckling the viewfinder.
So my question is: Is it possible to clean the focusing screen using say acetone or something?? has the screen had it forever? also how easy is it to replace the foam seals and buffer piece?
PS: Does anyone have a repair manual they could send me??
regards
Ollie |
ralph jones
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 14, 2005 - 06:00 pm: |
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Ollie:
The focusing screen on the A-1 is very easy to remove. With the lens removed locate the small screw just above the mirror foam bumper. Remove this screw and the screen retaining plate will fall out with the mirrow foam attached. The frame holding the screen will now come down and you can remove the screen for cleaning. Don't rub the screen, I soak mine in a warm water solution of dishwashing liquid and rinse with cold water and blow dry. Now is the time to replace the bumper foam while you have the mounting plate removed from the camera. Be very careful in handling the screen,they are easily damaged. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 14, 2005 - 07:08 pm: |
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Ollie,
If the retaining plate has not been messed with,it will not fall out when screw removed.There are two dimples on the back that hold plate in place so with camera lying on it's back you should lift the plate up and out,using tweezers and a finger to start it moving.The dimples are there for a purpose;when you put screen back you sit it in the hinged frame and slide the retaining plate upwards,lifting the frame.Gentle pressure locates the dimples and the frame will stay put.You can then locate the screw and tighten up.A touch of grease on the +head driver will stop you dropping the screw into the mirror box.
Note the way the screen is orientated as you remove it.Each of the long edges has a raised lip,but they are of different lengths.The longer edge is located at the back of the camera.
Soapy water in an ultrasonic bath is the best way to clean.However if you have crud on the screen careful wiping with a micro lens cloth just dampened with Naptha (lighter fluid) will remove,prior to a final soapy water rinse.Always wipe WITH the Fresnel Lines,never ACROSS them.The procedure is wipe once then if required wipe again with a FRESH area of cloth.Never use the same area twice and wipe in one direction,do not rub.Some say use Q Tips,but cotton wool can be very abrasive and the screens are a soft acrylic.
Seals and buffer are simple to replace,do the buffer when the plate is out of the camera.Look up Jon Goodman who trades as Interslice on eBay.His self-adhesive seal are the best and cheapest around.Kits contain every thing even a scraper, also specific instructions for A1 if you ask when you order.His email is,
[email protected]
For a free A1 Repair manual in pdf go to,
WWW.canonfd.com/choose.htm
Glenn |
Ollie
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 14, 2005 - 08:30 pm: |
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Dear Glen & Ralph,
thank you very much for your advice. I have managed to remove the focusing screen very easily, once I kn ew which screw to undo.
When cleaning the focusing the only thing I have are lint free lens tissues, will these be OK combined with lighter fluid or are they too harsh?? (forgive my ignorance but what is a micro lens cloth?)
Thank you also for the link to the service manuals. I don't suppose you know of any Rollei 35 srvice manuals about?? Also thank you for the contact about foam seals
regards
Ollie |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 15, 2005 - 10:51 am: |
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Ollie,
Lens tissue OK,just use as instructed above.Remember that you roll the tissue up into a cylinder,tear in half and use the torn edge fibres as the cleaning medium.If you ever come across any of the old Whatman Greens lens tissues buy them.Much better than modern stuff.A bit like the absorbent/nonabsorbent toilet paper syndrome!
Micro fabric lens cloth is very finely woven acrylic fibre.The cloth attracts dirt and lifts greasy marks.It is very soft and as long as you keep well washed,much better than tissues or cotton based wipers.
The so called lens pens use a similar fabric on the cleaning pad.As a point of interest there is a digital screen 'lens pen'which has a triangular pad,instead of the normal round one.This allows you to get into corners of viewfinders as well, but I have used just the angled tips to lift dirt from a couple of screens recently.Screen must be out of camera obviously,but the fine fibres obviously got into the fresnel ridges and removed the dirt.
Do a search in archive for Rollei 35 manuals.Somebody was talking about them recently, I think. |
Jan Dvorak
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 15, 2005 - 01:10 pm: |
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Ollie,
Just wanted to stress again - do not use any lighter fluid, acetone and such cleaners on the focusing screen. It is plastic and very easily damaged.
As Glen and Ralph mentioned above - the best is warm water with dishwashing detergent. If you have access to an ultrasonic cleaner, that would be even better. The trick is to touch the screen as little as possible during the whole cleaning and drying process.
Good luck,
Jan |
Ollie
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 15, 2005 - 03:39 pm: |
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I had to use some lighter fluid with a camel hair brush to get the gunky foam deposits off. I have now got my hands on a small sonic cleaner and have already put it through one 15 mins cycle with washing up liquid, but it still had a few marks on it, so I am going to put it through again after soaking for a while.
Is there anywhere where I could get a new (old) focusing screen if the problem remains??
Also is it possible to clean the mirror?? I heard that you shouldn't touch the mirror in case you mess up the TTL.
Ollie |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 15, 2005 - 06:26 pm: |
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I have some A1 standard screens,if you run into problems I will see if there is a really good one.However I must point out that these are ones I removed in first place because I was not happy with them for a 'back to new' restoration.Screens also come up on eBay,do not pay silly money as many are damaged.
Personally I find cleaning screens a doddle compared with mirrors.Bodies stored without body caps are the worse as the mirrors can become very greasy.On a couple of occasions I have stripped the whole mirror and backplate out and cleaned in the ultrasonic bath before dewatering with ethyl alcohol.I have used naptha and a fine camel hair brush to remove damper goo.You would have to really damage the mirror surface to make noticeable differences in the meter reading.Apart from camel hair brushes,the only other material that I have used to clean a mirror are pieces of micro fibre lens cloth.Unless the image is really degraded and the exposure way off,I would just gently dry brush. |
Leo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 28, 2005 - 01:00 am: |
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Listen good - this is your way out of this trouble. Buy at Home depot - Lowes etc. some "GOOF OFF 2" - do not use the regular harsh GOOF OFF since it may spoil your focusing screen.
I have cleaned several screens on Pentax and Chinon SLRs with outstanding results.
Use a small amount of the stuff - you dont want it to get inside your prism.
Do not touch any rubber or foam parts with this liquid. |
Ollie
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 01, 2005 - 09:10 am: |
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Glen do you hink you could have a route around to see if you have a decent focusing screen, not having much joy. Now I have cleaned it, i can see permanent marks on it.
Also what is the best way oof cleaning lenses?? it may sound like I silly question but is it best to use a brush then microfibre cloth with fluid or can just polishing with cloth do just aswell???
Ollie |
Glenn middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 01, 2005 - 06:44 pm: |
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Ollie,
Will have a look for a screen later today.See my comments on lens cleaning in the earlier thread.
Glenn. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 02, 2005 - 12:37 pm: |
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Ollie,
Send me your address details,I have found a good standard screen.Just one hardly noticeable mark on it-even fussy yours truely would use it!!
Glenn |
