strange voltage on ground path

[Dimitree]

Hi everyone
I was checking the voltages on my old Dynacomp, (original, '70).. The pedal works fine, so I was checking the voltage across the IC and the transistors.. Well, the strange thing is that I always get 8.3V on the ground path, while 9.2V on the +
If I check the voltages across the power supply, is it a normal 9.2V / 0V, but then it becomes 8.3V, so all the voltages across the transistors and the IC are not the usual one..
What it is wrong? the pedal works fine, I repeat..
I'm measuring with a 9.2V regoulated power supply, without the guitar plugged in, with the Sensibility pot at min.. Am I doing that wrong?

[R.G.]

It is possible that you're connecting the ground lead of your meter to the wrong place on the circuit. It's also possible that you have an open ground wire in the circuit so that part of it is getting ground voltage, part is not.

[Dimitree]

none of them.. 
I've put the ground lead across the - of the battery wire, then across the jack, then across the pot lug connected to ground.. And the ground path it is not open..I checked with the multimeter and there's connection between chassis and jack and pot and ground path on the circuit..

I'll try again

[R.G.]

I'm measuring with a 9.2V regoulated power supply, without the guitar plugged in, with the Sensibility pot at min.. Am I doing that wrong?

Is this one of the old pedals which only connect the circuit board ground to the battery (-) when there is a plug inserted into the input jack?