Fil, Camilla. WP#11031 CO2X :S/N 20706-21015D. Follow on from tips given in alog 67757 from laser company.

Summary: Touching RF cables made the CO2X laser power change 35W <-> 50W. We replaced one cable and now laser seems to be less sensitive and is locked with 49.1W out of the laser head and 0W into the vacuum.

When the Laser was outputting 35W, we measured the current drawn by the BNC/TNC between the Laser RF Driver and Laser to be between 4-8A.(Block diagram E1100892). While we were touching the BNC's on the laser side, the power out of the laser jumped to 49W and the current drawn decreased to ~0.2mA. 

We found that the laser power would jump if we touched any of these cables but only seemed to stay down at 35W when we touched the BNC cables on the laser. 

We tried the same on CO2Y and tapping or touching the cables didn't make the power change more than ~0.1W. 

We checked the grounding between the table and both lasers and cable. All seemed well grounded.

We found the upper left BNC (see attached photo) had the male connector not long enough. Fil replaced this RG-223 cable with a cable he made from LMR-195 of the same length. We installed the new upper left RF cable (BNC/TNC between the Laser RF Driver and Laser) and when we turned the laser back on it came on with 35W but jumped to 50W when I touched a cable on the on the RF Driver. 

After the cable swap, tapping and wiggling cables only momentarily spiked down to ~45W. See comparison left vs right plot attached. We are calling this a success but will watch the laser power over the next days/weeks to decide if we still need to replace this laser with the spare. We might also dive deeper into what we should expect through these RF cables.