So the HVT on my LPS went and did a zombie on me. Since I needed to replace my LPS I decided it was time to do a bunch of upgrades I’ve been sitting on. In addition to the LPS I also replace the tube (2.5yrs original). Also wanted to get rid of the digital control panel and go to a potentiometer and ammeter so I can see how much current I’m actually running. @donkjr was big help in getting me going on this upgrade.
To make the transition I did a series of measurements . With the new tube and LPS I first measured the voltage between the G and In pins on the LPS as a function of % on the digital control panel. I next hooked up my multimeter into the cathode wire of the tube to measure tube current as a function of power %. The a table of values and a chart are shown below. My new tube is rated at a maximum of 16ma which gave 38W when the tube was measured just prior to shipment. As you can see from the chart, I reach the maximum current at about 55% on the digital control panel. When you operate above the maximum rated current the power output (watts) quickly plateaus off and it shortens the life of the tube. So if you are just using a digital control panel please keep in mind that there is no real value in operating the tube much above 50%.