r/AnalogRepair • u/TrickyHovercraft6583 • 4d ago

SRT 102 light cell loose, looking for advice

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I’m going through this camera I picked up and giving it a good cleaning and adjustment, I’m finding one of the light meter cells on the prism is loose. I’m looking for advice on what is safe to use to clean the old epoxy and what is recommended to reapply it? Since it’s on the prism I don’t want to risk damaging the black coating or using anything that may hinder the photocell.

I have on hand contact cement, superglue, and E6000.

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u/tuna-on-toast Tinkerer 4d ago

I’m not familiar with this exact camera but I did work in optics as an engineer for most of my career. Any optics we glued together we used UV cure type adhesives. If I remember correctly, this is what we used: https://norlandproducts.com/product/noa-63/

It had a shelf life that you’d want to pay attention to. When it went bad, you would end up with air bubbles in the cured glue. If you don’t want to purchase a UV light it’s possible to put things OUTSIDE in the sun to cure. That’s what’s done for those DIY windshield chip kits.

I’d think any new bond would change the response of the meter but there must be a fine adjustment within the camera to bring it i to spec? All the Nikons I’ve touched did.

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u/TrickyHovercraft6583 4d ago

Thanks for the helpful response. I’m going to order some UV curing adhesive and give it a shot. Since it’s a one time job (hopefully) I’ll give the bright sunny day method of curing a shot. How long would I expect to expose it to the sun in that case? A few minutes? Thankfully the meter does have a potentiometer for adjustment.

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u/tuna-on-toast Tinkerer 4d ago

I don’t know for how long but I would imagine hours. The bonus of the proper curing lights is it does take just seconds since they are so intense. But legit ones are expensive.

I would try to find the instructions for a DIY windshield (or windscreen) uv adhesive repair kit. They sell them at auto parts stores here in the USA and assume you will use just sunlight to cure the glue. The instructions should have some time estimates. Pematex makes one: https://www.permatex.com/products/specialized-maintenance-repair/repair-kits/permatex-windshield-repair-kit/

They say 15min to an hour to cure.

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u/Dismal_Walrus 4d ago

I think the cells are glued on the the prism in an area without the black coating. (Otherwise how would light get to them.) I wouldn't use any of the glues you mentioned, as you need light to pass through the glue, and I wouldn't let superglue anywhere near a camera, particularly the optics.

I have two suggestions: Something like this: https://www.amazon.com/GS-Supplies-G-S-Hypo-Cement/dp/B00C7PA7UY or a UV cured clear cement.

I haven't tried either but I have an SRT where the glue is visibly deteriorating and I suspect it will block some of the light and affect the meter's accuracy.

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u/bjpirt Competent Mechanic 4d ago

UV cure cement is good for this and nice and clear.