In the UK you can find these things in "chemists" (pharmacies) and large supermarkets; prices vary, but they go for fifty or sixty quid or so. And currently less than £ 40 on eBay, I notice.

I doubt that a proper service manual has ever been made available.

Have you got the "piece of paper" (OK, "leaflet") that serves as an Instruction Manual?
But "static pressure"? The Omron works on the oscillometric method. What are you trying to do ... test it?
