P Speed focal plane shutter repair/DIY/info schematic etc…any gurus in here?

[Memento Mori]

Good morning to all! I am getting started on my LF project and need some help. I did basic light leak/focus/lens shutter testing on my new 1953 Pspeed the other day with some surprising results. The result that brings me in here today is the two frames I shot using the FPS came out exactly the same even though I shot them at 1/30th and 1/50th. So, it appears that the little lever at the bottom that shifts between the two groups of shutter speeds is needing my attention.
I have that wonderfully comprehensive “War Dept” manual but it’s for a 1947 model with the very different focal plane shutter mechanism.

Anyone know how exactly that group selector lever works? Or where I can find a repair manual for the later model FPS?
I’m shooting wide open on my lenses and need the flexibility of 6 speeds…
Cheers!

[Dan Fromm]

Have you looked here: http://www.southbristolviews.com/pic...cmanuals.html?

[Memento Mori]

Have you looked here: http://www.southbristolviews.com/pic...cmanuals.html?

Yes! Thank you. I now have an exploded view of my FPS mechanism, but no explanation of how it affects the shutter speeds. I already disassembled much of the area to tighten the tension on the curtain so I guess I’m goin back in!
From the looks of it, the little pot shaped “brake drum” spins, and the little plunger pushes out on it just like a brake.

I was hoping someone who had already dealt with this would chime in.

[Yourix]

Between 1/30 and 1/50 it's not even a stop... Minus spring un-accuracy and tolerance, plus film dynamic range... No wonder they look exactly the same.

I don't know your shutter but I recently tested two Thornton-Pickard FPS that I refurbished and while you can set speeds from 1/15 to 1/90 I found that in reality the top speed was 1/25. I tried tensioning the spring but it had almost no effect. I don't want to damage it so let it as is.
I think you can't expect much from an old mechanism like that. One or two usable speed are enough for me but If you want more you may have to change the spring.