Tektronix 7603 with 7B53A and 7A26 plug ins

[Nick]

It may help that the US military has a National Stock Number (NSN) for this part - NSN 5962002368572 or 5962-00-236-8572 with the correct formatting.

Seems it was used (i.e. in the Tek 7000-series scopes) in the support of various interesting US military projects (source:http://www.parttarget.com/5962-00-236-85...21-00.html):

• Strategic Weapon Systems(Poseidon and Trident)
  
• Aircraft, Eagle F-15
  
• Ballistic Missile Early Warning Sys. (Bmews)
  
• Support Equipment, F-15 Aircraft
  
• Ticonderoga Class Cruiser(47)
  
• Arleigh Burke Class Destroyer
  
• Fms - Knox Class Frigate
  
• General Purpose Electronic Test Equipment (Gpete)
  
• Calibration Standards Equipment
  
• Fms - Build Frigates Class Ships