With the Hammarlund HQ120 that I recently purchased, If been having a great time DXing on all the bands and learning the in's and out's of this particular Vintage radio operation. However, yesterday I lost my OD3 tube. While working, I noticed that it put off a what appeared to be... ultraviolet or bluish colored light, and about mid-day the radio quit working. Wondering what might have went out, I let the radio return to room temp and later turned it back on with the top lid opened a couple inches to view the bulbs in operation. From what I could see, they all lit except the OD3 tube which I initally noticed because of the color, so I asume that is the cause of inoperability. I got online and bought a tube kit which included a complete HQ120 tube-set. I have no idea of course as to the lifespan of the old 'original' ....OD3 tube and if it's 'is' original or has been replaced sometime in the life of this radio.

Back to the title of this post.... should one operate the HQ with the lid opened for cooling or add additional fan cooling from an outside source? Also I was operating this in an enclosed cabinet with sides, top and back, with about 8-10" of open space all around the radio? The inside temp of the room was probably 60 or so degrees, so it was typical cool fall weather. SHOULD I also cool and have the hood open? and should it be in a more open environment? Thanks......... Plotus AKA Richard...