[volt-nuts] Integrator errors from dielectric soakage?

[Charles Morris]

I recently repaired a Weston 4442 (3.5 digit dual-slope DVM) which had
a failure of the integrating cap. It had decreased in value from 2.2
uf to 0.42 uf; a radial-lead green "box" containing an unknown
dielectric) Not having a suitable polystyrene or Teflon cap in the
junk box, I used a handy polyester cap (looks like an orange-drop but
white epoxy).

Any ideas as to how much error the (presumably) Mylar integrator cap
will introduce? In other words, will such error be significant in a
mere 3.5 digits? (I imagine that Weston would have used a less
expensive cap if it would do the job). The absolute value isn't
important due to the dual-slope technique, but time-variant storage
effects are...

I have an HP 4.5 digit DVM and a MAX6385 (2.5 volt) reference, but no
"volt-nuts"-league meters or standards, other than a 596.5 ohm 0.01%
resistor ;)

thanks
Charles