HP 10529A Repair Question

I picked one these and it has LED's 13 threw 16 lit in the test mode all the time. Problem points to U6. Quad 2 Input NOR Gate. TI SN4467, HP 1820-0328.

When the output is low the Led lights up.

It looks like the replacement would be a SN7433, Quade 2 input NOR with

open collector.

Can someone conferm this.

Dose anyone have a cross reference to the HP IC part numbers for this model?

Thanks

RJ