Weird light leak in Yashica TL Electro

[Mr_Flibble]

Bought a Yashica TL-Electro with a Yashinon-DS 50mm f/1.9 for the awesome sum of $3 at a flea market. The lens is in great shape, but the camera needed some attention.
I replaced the seals and mirror bumper with a replacement set ($10 + shipping from ebay)


But I still get this light leak in a few frames per roll:

As you can see it appears to starts at 1/4th from the bottom of the frame and fans out into the middle. (So I guess the leak is somewhere at a quarter from the top of the film in the camera).

The leak runs horizontally across several adjacent frames, also over the blank space between frames.
It's got me stumped at the moment.


Any ideas would be appreciated,

 

[bsdunek]

It may not be from the back. Look to see if it's coming from the top, inside of the camera, that is, from the viewfinder area. I've seen that happen.

 

[Mr_Flibble]

Thanks Bruce,

The light has to get round the top of the shutter curtains somehow. Hmmm I'll see if I can take the top off. Wanted to clean some dust out of the viewfinder anyway.

 

[Mr_Flibble]

White fogging on color negative film (fujicolor 200) seems to indicate the light leak is on the emulsion side

 

[Greyscale]

You may have left too much of a gap around the counter reset switch in the top channel on the back.

 

[John Hermanson]

Is there a foam seal around the perimeter of the back cover? If so, have you replaced it? Light leak can go through the backing of the film too. John

 

[Mr_Flibble]

Yeah, it's has a brand new seal set installed, and no gap around the counter-reset button in the grove.

considering the sharp edge to the leak I think it might be coming from the shutter curtains/mirror area.

 

[Mr_Flibble]

Finally had the top of the camera off yesterday (with a little help of the assemlbly PDF), but still none the wiser of where the leak might be located.

 

[bgb]

Any chance the back is not perfectly flat ? If the seals are good there should be no leaks like that ... is it possible the foam is too thin? I'm guessing but ya never know 🙂

 

[Mr_Flibble]

Thanks for the idea,

I'll take a look at it this evening.

I've read something about the film roller on the back cover being held on by two screws that are bolted straight through the back. Their heads covered by leatherette.
I recall one of the spots being particularly lumpy. But if this was the source of the leak I would have thought the color of the fogging would be different.

 

[Mr_Flibble]

Found it!

The little foam cushion underneath the VF eye lens has shrunken/deteriorated. This lets in light in along the top of the shutter curtains run. Right between the curtains and the film. Should be relatively easy to fix!

Thanks for all the ideas!