The Case of the low Amperage

Issue as reported by customer:
Reduced power of laser, 18mA where it should read 28mA+
other factors included a failed and replaced 150W PSU as well as a replaced CO2 tube at 130W.
Customer has “tried everything” and is convinced there is a problem but can not determine the problem.

Diagnostics on site:
Inspection of PSU and wiring of tube to ensure all good.
Removed PSU from machine and tested with dummy load and a new mA meter using a power lead directly into the mains. PSU shows 40mA reading on touching the TEST button on PSU.
Reconnected to the customers CO2 tube to test if the tube strikes (signal connection removed from PSU) using TEST button. Tube strikes and mA meter shows normal amperage.
Test using machine power as above with same result.
Test using customers machine amp meter, which reads 18mA
Rigged my amp meter to customers amp meter wiring with same result. Beam unaffected.
Inspect machine and find that the downward alignment is off. Beam is clipping the cone on exit from the lens, reducing power output at the work piece.

Realign machine.

Remove and replace wiring from cathode cable to amp meter test and if needed replace amp meter.

Note: In other cases where half expected amperage has been found, it has been an indication of a failing PSU where one of two transformers has stopped working producing half the required load for the tube.