Greetings to the group, hope all of you are doing well, staying positive and testing negative!
I'm still going through the estate of a deceased collector of test equipment and recently came across a sealed bag from MAXTek dated Jun 2004 of these 165-2389-00 (H2389) hybrid ICs.  Google says they are used for the Tek TDS400 scopes.  But, no schematic to confirm that.  So, if you have one of these scopes, I have (what I believe to be) New old stock of these hybrid attenuator IC's.  The sealed package contains 20.  I'll keep 4 of them and offer the remaining 16 of them to the group at $35 USD (each) plus shipping costs.  Please email me at n7qj@arrl.net for pictures and additional details.  
Thanks and Regards, Ryan Scott
N7QJ