[Amps] Old HP analyzer needs some repair

[Bill Turner]

I have an old HP 4191a Impedance Analyzer that needs some repair. HP no 
loner supports this model so I'm wondering if anyone knows who might do 
the work?  It boots up and goes through the self calibration procedure 
but the impedance readings are totally wrong. It's a great old machine 
and I hate to scrap it if it can be repaired at a reasonable cost.

Any suggestions will be appreciated.

73, Bill W6WRT