Actually here are few problems.
1. When I turn wheel to capacity, it shows 66pF (without leads). It is offset, but stable. Is it possible to correct offset?
2. When I measure say 470uF (on auto range), it shows ok. Then I disconnect this cap and... device starts to jump in different ranges, shows different values, include negative; and this may last infinitely or sometimes it returns to 66pF. If I connect say 40nF while it is jumping it shows 40nF correctly and upon disconnecting it returns to 66pF (always). Or I can turn wheel forth and back to capacity to return it to 66pF.
3. DC mV sometimes shows tens of uV with probes shorted, sometimes few uV, and sometimes 0 or negative values (unstable).
4. AC mV shows ~150 uV with probes shorted (stable?). Reduces few times if I keep my hand nearby multimeter (even not touching it).
5. AC V shows ~3mV with probes shorted (stable?).
Device is very clean inside, also outside.
Any suggestions?