HP 46 repair

[AndiGer]

What is the best material for lubrication?
What do you use for those old machines?
Often hardened grease is told to be the problem of breaking the printer's hammers ...

I have an HP-81 and an HP-46 to care for ...

The HP-46 suffers from the printer not working at all. Does not run the printer motor even when PRT OFF pressed while powered (so being very silent when powered on but not the kind I hear when I turn the HP-81 on).

PRT OFF pressed down when powered runs the machine as desired. Calculates everything ok. PRT OFF released (i.e. print should be done) and powered just gives a hardly to hear "Cilck" and the machine does not turn on. PRT OFF released after successful power on and some print request gives error on Option 1 display and needs power off (another "Click" to be heard) to reset the machine.