Ext 10MHz for Hameg HM8021

For a long time I wanted to calibrate the Hameg 8021-2 to my external 10MHz GPSDO. But, unfortunately, the crystal oven is not very stable. My thought was, why calibrate if you can use the back BNC connector to feed the external 10MHz signal from the GPSDO? So, this was an easy task. Find the internal 10MHz, disconnect it, connect to rear via 1nF capacitor. Done ;)

Precise 10MHz counted from back BNC, which also provides 10MHz ref signal
Cable routing for stability
Disconnect at the black marked point, then connect back via 1nF
Connect at front switch via 1nF