Spring is Sprung ! ! !

I'm hoping that somebody out there can help me fix my SMCP-A 50mm 1:1.7 lens.

I have a second lens that has suffered the same fault as a previous one which I had repaired, that is, the aperture ring refused to move past f11 towards the A setting.

Not wishing to pay the £25 + postage to have this one fixed I thought I would have a go myself. Dismantling the lens wasn't an issue, neither was finding the problem, a broken mount for one of the 2 little leaf springs on the lens body inside the aperture ring. The spring had shifted and jammed.

Fixing that wasn't a problem, araldite rapid to the rescue and job's a good un. Fixed.

Trouble is, putting it back together wasn't without its difficulties. That little ball bearing that produces the satisfying click of the aperture changes was a so 'n so to keep in the right place. I even managed to get the A detent back in too.

Now, that little spring that fits inside the one and only electrical contact has grown legs and disappeared.

I was sooooo careful not to drop any bits and I had it on the end of a magnetic screwdriver ready for refitting the contact but . . . its gone.

Has anybody got an old lens that they could spare one of their springs to get my lens going again?

Here's the rub, I just sold an old A lens on Ebay for spares and repairs. I new I should have kept it.

If you can help me, PM me for my address subject to agreeing a fee + postage of course.

Thanks in anticipation.

BTW, If anybody else feels the urge to do a diy repair on a lens, don't unless you know what you are doing. It's taken me several hours to get this far. £25 seems very good value for money to me now.

I had the same problem exactly with a SMC Pentax-A 50mm f1.7 lens and I tried to repair it as well. I failed miserably and now would not dream of opening another lens. Well at least not with any anticipation that I would be using it again!

3 tips for finding lost springs...for those with loose screws also:

1) Magnetic Bingo Wand.
2) sticky tape lint roller.
3) good flashlight (torch) laid right on the floor to provide strong sidelight.

John,

I was feeling so pleased with myself too . . . until that darned spring disappeared. I've even been over the carpet with a magnet, twice. Dismantled my desk thinking that it had rolled into a drawer. Nope, gone.

Really exasperating.

I don't suppose you've still got that old lens in bits in a box somewhere ? Still, even if you have, chances are the same spring is missing

Hi Peter,

what are the dimensions of the spring, roughly?

I'm just off out, but my idea was to use the flint spring from the inside of a lighter.. cut to length, or one from a retractable ball point. The latter, I'm sure you'll have somewhere, and if you don't smoke, ask someone who does, for the former. They're bound to have loads of old disposables lying around.

Cheers

Liam

Nice idea Liam, but that's way too big. This spring is no more than 0.5mm in diameter and about 2 or 3mm long. It really is tiny. That's probably why i can't find it. I have loads of springs from my typewriter repair days (remember them) but they are all elephant sized and I need mouse sized ( very small comparatively speaking ). I think only a similar spring from a defunct lens will do.

To give you an idea of the size, if you look at the contacts on an A or later lens, it looks like a ball bearing but it isn't, its a tiny tube with a rounded end. This spring fits inside it. it really is miniscule and I take my hat off to the people that built these lenses and anybody that repairs them, their eyesight must be superb.
Thanks for the idea anyway.

Peter
I had the same scenario when I opened up my FA 135, even though I knew there were springs in the contact assemby I still managed to let a couple fly.

Took me a while scouring the carpet with a maglite and a 4" magnifying glass to find them. Don't think a magnet will do as I reckon they are made of very fine brass wire, could be nickel plated but they look to shiny, probably too small to plate as well.

It's a bit tricky to fit them back onto the contact pin too, I had to get the youngster with the A+ eyes to do it for me.

Happy hunting..........

Oh!..... and one was stuck on the end of a cat hair which was in turn clinging to my trouser leg....

Picture me, grinning like a cheshire cat.

I found the spring with the aid of a magnet ripped off of an old PC speaker.

I combed the carpet inch by inch around where i've been working and after about half an hour of searching, there it was, stuck to the magnet.

Its taken me another hour to reassemble the contact, yes, just 3 pieces but they are very small, and one piece is this darned spring.

Well the lens is back together now and working well.

I've learned a number of useful things from this exercise.

1: Don't take lenses apart unless you've got a day or two to spare and you don't necessarily need it to work again.
2: Don't buy deep pile carpets, ever again.
3: This is the sensible one, store all A lenses on their A setting when not in use so as to relax these little leaf springs that seem to break their mounts. On anything other than A, one or both of them is always compressed, probably the one that breaks, causing a permanent strain on its fixing.

For those who haven't experienced ( read 'been daft enough to try' )taking one of these apart, when the aperture ring is set to A, the little button that you press to move it to the A position pops out. It pops out under the pressure of one of these little leaf springs. The spring is fixed at one end, in a very cheap way I have to say. During manufacture, a hole in the fixed end of the spring is passed over a plastic post, the top of which is then melted to hold the spring in place. Its the melted bit that broke on mine leaving a tiny plastic post and causing the spring to be incorrectly aligned and jamming the movement of the aperture ring.

Thanks to all for your suggestions.

So glad you found it. I was going to suggest that if you have a wife or girlfriend you should call her out to the workshop. You've been searching for the tiny lost widget for an hour, trying all the tricks. She says, what's the matter. You say I've lost this little critical spring that holds (fill in the blank) what is, essentially, my whole world together.

She says, what's it look like? You describe it. She looks around and says, rather too offhandedly, it's right over there by the footstool, and walks out, clearly disenchanted by your incompetence.

Ted

I have one of these A 1.7 lenses. And it is quite difficult to move the aperture ring on a certain F-stop. If I move it off the A setting, it's quite difficult put it back there. That's why my A 1.7 never leaves the A setting nowadays.

After reading this thread, it looks like it's a common problem on these lenses.

Do you think it might happen to my beautiful A 1.4? I remember reading they are made with better quality...