Bolex Viewfinder Grime + Bolex maintenance/S16 conversions?

[Gerrit Fahr]

I have a Bolex H16 Reflex, with a serial number that should date it to 1972. I have tried to shoot with it once, but found once I had the appropriate gel 85ND filter and f-stop - the image was so dark, revealing a layer of 'grime' (for lack of a better word) in the viewfinder so that I could barely make out focus. Alas, I just recanned the film and came here. 

When I adjust the eyepiece diopter, it reveals a layer of scratches when focused to itself (that seems to be a separate issue), but when I focus to the ground glass, this aforementioned layer of grime comes into view. Could this buildup by inside the viewing tube or on the ground glass itself? I have attached a photo of this buildup. 

Any tips on how to clean this? I've taken apart the viewing tube to clean it myself to no difference. 

Additionally, any recommendations for places to get a Bolex some CLA and potentially upgrade it to S16?

[Dom Jaeger]

If you’re in the US, try Procam or Du-all or Dr Bolex. Jean Louis Seguin is probably the best Bolex tech in the world but I’m not sure if he has retired from Bolex servicing  and conversions.

Bolex reflex viewfinders can be a bit dim, but yours looks like it needs a professional clean. Check your lenses aren’t fogged or have coating damage, same for the reflex prism. If the top viewfinder is too dim you can use the non-reflex door mounted finder on the side for framing, which is unaffected by gels or f stop, and only use the top finder for checking focus at max aperture. 

[Gerrit Fahr]

47 minutes ago, Dom Jaeger said:

If you’re in the US, try Procam or Du-all or Dr Bolex. Jean Louis Seguin is probably the best Bolex tech in the world but I’m not sure if he has retired from Bolex servicing  and conversions.

Bolex reflex viewfinders can be a bit dim, but yours looks like it needs a professional clean. Check your lenses aren’t fogged or have coating damage, same for the reflex prism. If the top viewfinder is too dim you can use the non-reflex door mounted finder on the side for framing, which is unaffected by gels or f stop, and only use the top finder for checking focus at max aperture. 

Don't have a non-reflex finder unfortunately, but thank you for the recs!