It still sounds like your LPS is not putting out full power.
The attached diagram shows how to connect a DVM to measure the current in the tube.
Summary of the measurement
The tube’s anode is connected to the HV side of the LPS (stay away from this end)
The tubes cathode (the other end of the tube) is connected to ground at the LPS.
The cathode wire is typically green and connects to the FG pin on the left-most connector of the LPS.
We are going to put the DVM in series with the cathode side of the tube and ground and measure mA.
Setup the measurement
- Disconnect the green wire at the LPS and connect it to the plug labeled mA on the front of the meter.
- Connect a lead from the COM plug on the meter back to the place where the green wire was connected on the LPS. This should be FG on the leftmost connector of the LPS.
Set the dial on the meter to the DC amp scale (has an A with a dotted line under it).
The meter should read the cathode current in milliamps typically between 0 and 30.
Map your current output vs the % set on your digital control panel.
- Set the control panel power to 10%
- Close all covers, enable laser
- Push and hold the fire button and read and record the value on the digital meter
- Increase the digital setting by 5%
- Go to step #3
You will end up with a table like this
% power setting tube current
An example table is here: https://donsthings.blogspot.com/search/label/K40%20Laser%20Power%20Supply
[ignore the rightmost column]
Cathode wire at the LPS:
Cathode wire at the tube: