GM328 Transistor tester wrong battery voltage

[james3]

Hello,
I just finished to assemble my Transistor Tester GM328, everything seems to work fine less than the battery voltage value that is always more (when I plug 9V it says 20V, when I plug 6V it says 18V)  Any idea what's wrong ?

UPDATE:

I just found that I misplaced the 33K and the 3K3 resistance, now that they are in the right place it works perfectly