I was already building a switch mode HeNe laser when ex-UCC president David Emrich e-mailed the UCC list putting the historic 'siliconed components on perspex' laser up for sale. So after a brief exchange of notes I was off to the northern suburbs and returned with the scary monster itself...
|Basically all the components are stuck down on a bit of perspex with silicone (anti carona) and mounted in the 'less than Australian Safety Standards' cardboard box. It is so end heavy that the whole box can be balanced on your palm at the left edge!|
|A closeup of the perspex board. The HV multiplier stage is on the right, two large blocks of current limiting resistors can be seen in the middle and the startup caps at the top.|
|The beast transformer. 240VAC primary, 960VAC secondary! Pretty damn heavy too!|
|And burried beneath the perspex board wedged between bits of polystyrene is the tube itself (again mounted on a bit of perspex)...|
|Well the laser warranted
just a bit of work so I set about rebuilding it to make it a little
more safe / substantial. Many hours were spent using a razor to shave
the silicone off the tube and cleaning up the components.
After resoldering / rebuilding the supply I cleaned up a bit of perspex and cased all the parts in "Dip-It" a rather nice clear rubber compound from the local hardware. It is strong, very flexible, good adhesion, insulates well and is easy to remove if required (OK, easier than silicone anyway...)
And here is final product. A far cry from the original housing! I added a second tube to the enclose as well as a safety switch in the lid to avoid people getting zapped.
The Big HeNe Tube / Switch Mode Supply
This beast (from Oatley Electronics - see the link page) is a very compact device with an output range somehwre in the 7mW range and tightly collimated (looking in to this beam would be a BadThing )
|This is the assembled unit. It is constructed in a length of 50mm SWV pipe and painted with matt black and laquer. The laser head is substantial and occupied about 2/3rds of the tube.|
|This is the laser "exploded"|
|This is the switchmode supply with the HV end conveniently dipped in more "Dipit" compound.|
Law requires certain warnings to be adhered to laser devices. Included here are labels of my own design.