Mono preamp (K1803) - how to adjust RV1?

Hi guys,
Assembled kit K1803 (universal mono preamplifier) as per instructions. I’m getting a voltage across the circuit so looks like it’s working.

But how do I adjust RV1? There isn’t any pot knob on it…is this via a matchstick or something?
Sorry if it’s a stupid one, but can’t seem to find the method in the manual.

Cheers,
Jon

How about a small blade screwdriver… :slight_smile: