HP Nixie tube display card

[judge]

I bought some HP display boards recently and I am wondering what they were used in. They had B5441A and B7221 Nixie tubes in them, so I suspect a calculator (decimal points and sign tubes). In fact they also had B54370A tubes, which I can find no information on at all. These tubes have a left hand decimal point and a right hand comma.

Anyway, as I say, it would've nice to know what the boards were used in.

There should be an attachment, but I am doing this on my phone, so who knows?

[edpalmer42]

A few minutes with Google would have told you that it's from an HP 5505A Display that's part of a 5526A Laser Measurement System.

[judge]

Thanks! I spent more than a few minutes with google 

[edpalmer42]

All I did was put in the part number on the circuit board.  That usually gives you at least a couple of hints to work on.  In this case, it gave me the user/service manual.