开云体育

-------- Original message --------From: Glenn Little <glennmaillist@...> Date: 1/2/21 6:26 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Slightly OT: How can I dissolve Potting Compound? You can try MEK, methyl ethyl keytone.It will dissolve a lot of epoxies.Be careful to not dissolve other things.73GlennWB4UIVOn 1/2/2021 9:18 PM, Dennis Tillman W7pF wrote:> I need to dissolve the black HV potting compound of a 12VDC powered> Helium-Neon laser inverter power supply I have that stopped working. I would> appreciate any suggestions on what works to do this. I’m guessing it may be> epoxy. I stuck the tip of a hot soldering iron in it for a few seconds> without much effect.>> When it was working it turned out to be perfect for powering gas filled> Spectrum Tubes. These spectrum tubes (smaller versions of neon signs) filled> with a variety of gasses are an excellent source of spectral lines for the> 7J20 / J20 Rapid Scan (Optical) Spectrometer to measure.>> Spectrum tubes require an initial high voltage (1,000V to 1,500V for> example) to break down the gas and start it conducting. Once the gas in the> spectrum tube conducts the voltage across the gas drops (250V to 450V for> example) and unless you limit the current (to a few mA) it will destroy the> tube. Can anyone can point me to a source of information on how to determine> the proper voltage and current I need to power these spectrum tubes? Is> there a web site or group devoted to Spectrum Tubes?>> Something happened to the inverter and it stopped working. The input is now> open. The inverter is a black potted brick 3” x 1?” x 1”. The ballast> resistor has continuity so that is not the problem. The original label on> the inverter is partially destroyed so I can’t tell what its initial high> voltage output was or what it current limits at. All I do know is that it> was made by> Laser Drive Inc.> 5465 Wm. Flynn Hwy. Gibsonia, PA 15044> Model: 1150-6330, S/N: 610574> The input was +12VDC at 0.35A.>> I wrote to the company that took over the company that took over Laser Drive> Inc. asking if they could tell me the output voltage and limiting current> but I didn’t receive a reply.>> At this point I am hoping if I can remove the potting compound I can figure> out what went wrong with it.>> I have a different, bigger Laser Drive Inc. potted inverter which is powered> by 115VAC. It puts out 2350VDC at 6.5mA. This causes the Spectrum Tubes to> flicker. They do not run continuously. I am guessing that this because 6.5mA> is more current than the tube can conduct. The amount of current the tube> draws increases in proportion to the inside diameter of the tube but I don’t> know much about this matching the power supply to the tube. All I do know is> the one that went bad seems to be an ideal match for the spectrum tubes I> have.>> Battery operated (DC input) inverters are much more desirable than AC input> inverters for this application because the AC rectification and poor> filtering shows up on the output DC as significant ripple causing the> amplitude of each spectral line to be blurred.>> Dennis Tillman W7pF>>> >>-- -----------------------------------------------------------------------Glenn Little??????????????? ARRL Technical Specialist?? QCWA? LM 28417Amateur Callsign:? WB4UIV??????????? wb4uiv@...??? AMSAT LM 2178QTH:? Goose Creek, SC USA (EM92xx)? USSVI, FRA, NRA-LM??? ARRL TAPR"It is not the class of license that the Amateur holds but the classof the Amateur that holds the license"