[Test-Equipment] HP Multimeter

[j.foster]

Greetings All:

                   I have two HP 8840A 51/2 digit DMMs both with non-working AC ranges
(you press the AC button and an error message is displayed).   DC ranges are OK.
   HP quote several hundred dollars each to fix (blanket "covers most repairs" rate). Anybody have any idea if these are likely to be repairable "at home".  ie by buying an IC, for example,
from HP (no doubt at a steep price but hopefully less than above quote)

TIA   J. Foster.