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?