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Re: Slightly OT: How can I dissolve Potting Compound?
Dennis,
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A chemist friend once told me to try Dichloromethane. I have successfully unpotted two assemblies using this. First, it is nasty stuff, I put the part and the Dichloromethane in a glass jar with a tight fitting lid and left it outside in the sun. The jar was about half full and completely covered the part. If anything happened to the jar, it would just spill into the driveway. I did this in a reasonably warm part of the year. It would boil from the heat of the sun, condense at night, and do the same the next day. A tight fitting lid contained the liquid for months. Second, it is slow. I unpotted a motorcycle voltage regulator and a 7904 HV multiplier. In both cases, it took over a month. Third, it will eat anything plastic. It doesn't know the difference between potting compound and the plastic case of a diode or transistor. Fourth, frequent investigation can get you info. On day 10, a transistor may become partially visible, make note and move on. On day 15, a diode may become visible, and the transistor from day 10 might be just the metal lead frame and die. Looking every few days will yield new info. If you catch it at just the right time, you can make electrical measurements of the partially exposed leads. For the 7904 HV multiplier, all the ceramic caps were stripped of insulation but the leads and conductors were still there. The output resistor was still measurable, as was the low voltage feedback diode, which was the mystery for me at the time. I was even able to carefully measure a diode and a capacitor before the leads fell apart. It just depends on how desperate you are. As others have suggested, purchasing a new one would be far easier. And there will be no chance of repair, just the possibility of capturing a schematic and mechanical details. Tom Bowers PVH Engineering " " Dennis Tillman W7pF via <> groups.io 7:18 PM (4 hours ago) to TekScopes I need to dissolve the black HV potting compound........ " On Sat, Jan 2, 2021 at 11:31 PM Dave Seiter <d.seiter@...> wrote:
I've found that nail polish remover can have weird stuff in it (besides |
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Re: Slightly OT: How can I dissolve Potting Compound?
On Sat, Jan 2, 2021 at 10:31 PM, Dave Seiter wrote:
Yup. Some nail polish removers use acetone. Some removers use ethyl acetate or MEK or both. Remember MEK is used in the "glue" that plumbers use to solvent weld together plastic pipe.... in other words... it softens (and would dissolve) the plastic. |
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Re: Slightly OT: How can I dissolve Potting Compound?
On Sat, Jan 2, 2021 at 06:18 PM, Dennis Tillman W7pF wrote:
Hi Dennis: I couldn't remember... but finally did. There is the defacto go to FAQ... for "gas laser tube nuts" called "Sam's Laser FAQ" ... there is good bit of information about He-Ne laser power supplies, et. al. (No relation to the schematic service, for T.V. repair... and not a quack [ is/was a prof. and has a PhD, if that precludes that sort of thing.] ) Gas discharge laser tubes are similar to "spectrum discharge tubes" ... at least the spectrum tubes I'm familiar with. There's several scientific supply houses, in the U.S. that sell those spectrum tubes (but, I think they are all made in China.) The tubes I'm thinking of are about a foot long, have cold cathode electrodes on either end, and are made of glass. |
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Re: Slightly OT: How can I dissolve Potting Compound?
I've found that nail polish remover can have weird stuff in it (besides the obvious dyes and fragrances) that pure acetone doesn't.? Last summer I poured half a bottle into the plastic tub of a cheapo ultrasonic cleaner, and it immediately started attacking the plastic.? The thing is-? I've used pure acetone in that tub many many times and it's never touched it.??
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-Dave On Saturday, January 2, 2021, 09:09:47 PM PST, Roy Thistle <roy.thistle@...> wrote:
On Sat, Jan? 2, 2021 at 08:38 PM, Jim Ford wrote: Gasoline is worse, but... MEK is listed as a precursor... but a lot of industrial chemicals are precursors... and despite being listed... it produced, and used in vast quantities, in the U.S. Model airplane "glue" (actually solvent welding, not gluing) has it, plumbing "glue" has it (dido of welding plastic pipe)... it's used in a lot of products sold to the public. If plumbers and kids can handle it... well... It's not "particularly good" at dissolving the black epoxy potting compound, after it's cured... but, depends which epoxy was used... and given a long time... it might dissolve it. Acetone works better. (But, don't tell your wife of the horrors... or she might have nightmares after she does her nails.) |
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Re: Tek 465 Negative 8 volt rail issues
To wrap up my PS cap replacement:
I replaced all 5 power supply filter caps. See thread above for details on replacements. I spent a couple of afternoons carefully pulling old supply caps. With all the new parts in hand I got the new caps and adapter boards put together in another afternoon. The next day I spent the morning installing the new caps. See photos in: /g/TekScopes/album?id=258720 For the large negative terminal holes in the A9 board I used a pieces of aluminum ducting tape. Not silver duct tape of Mythbusters fame, but actual aluminum foil tape used for sealing stove exhaust vents. I used a three-hole punch to make nice little circles that matched the trace pad around the large hole. I just needed it to stop the solder from running through and pooling on the cap. Worked pretty darn well. By afternoon I had everything put back together, held my breath, and pulled the power switch on. Nothing. Not even a low voltage light. No channel indicator lights, no trace. Turned it off. It didn't take long to find the problem. I first checked the outputs of the rectifiers at the new caps. Good voltages and no more deep voltage dips. Output of 110v regulator good, output of 55v regulator 0v. Or just a couple of volts. After some investigation I found that the 57.3v at the anode of CR1532 was zero. Strangely the voltage at R1528 was zero, tho the + terminal of C1512 was fine. Tracing the trace between R1528 and C1512 I discovered that the via through A9 at the + terminal of C1512 lost its metallization when pulling the old cap. With no metal in the via reflowing the solder on the cap pin didn't allow solder to connect to the other side of A9 and left no connection to the trace to R1528. It took several attempts today to try to replace the metal via. I tried aluminum foil, but the solder wouldn't flow on aluminum. I realized I needed to use copper, and had some copper foil. I was able to reinstall C1512 and confirm the continuity to R1528. So finally all caps are installed and working now. I've started the calibration procedure and all PS levels are working perfectly. Setting the 55v supply to 55.0v results in all other supplies being within 20mV of perfect. I've a ways to go through the calibration, but I'm back where I was when C1513 failed. Dave |
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Re: Tek 577 D1 Repair (B07xxxx)
6. B072023
2020-Nov-15~30: Broken Trace The last trace's broken into two traces:1st half of last trace and 2nd half of base trace. </g/TekScopes/photo/255563/24?p=Created,,,100,1,0,0> The solution:Mod c265 1uf --->0.27uf on A1 Board,to improve discharging timing. /g/TekScopes/photo/255563/25?p=Created,,,100,1,0,0 /g/TekScopes/photo/255563/26?p=Created,,,100,1,0,0 7. B072023 & B108637 (Mod:11 Steps) 2020-Dec-1~15: Retrace / Double Trace issue(even steps) </g/TekScopes/photo/255563/21?p=Created,,,100,1,0,0> I prefer to eliminate the double trace and keep the 10th step,my solution is 11 steps(12 traces) why 11 steps(12 tarces)? a.it will eliminate double trace. b.refresh rate/per trace: 11 traces(10 steps): 240/22 traces(11x2,double trace)=10.9 times/s 12 traces(11 steps): 240/12 traces(no double trace)=20 times/s c.12 traces is 3 times of 4 (zero crosses):this will improve flickering. The solution is simple and easy(eliminates double trace issue only at Fast step rate): Put a 68K ohm resistor(>=1/4 W,5%) in parallel with R319(9.76K,A1 board) new R319=68kx9.76k/(68k+9.76k)=8.535K ohm New voltage of Pin 3 of U305B(adjustable by "Number of Steps"): Min:30mV(1 step) to Max 4.75Vdc(10 steps)------->Min:26mV(1 step) to Max:5.28Vdv(11 steps) Before and After: <;feature=youtu.be&ab_channel=JackSu> </g/TekScopes/photo/255563/26?p=Created,,,100,1,0,0> </g/TekScopes/photo/255563/27?p=Created,,,100,1,0,0> </g/TekScopes/photo/255563/28?p=Created,,,100,1,0,0> By changing R319 we can get more max steps(max 12v/0.5v=24 steps). |
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Just a quick note, I have updated the files yet again for those who have downloaded them in the past.
I added cutouts to the card edge connector to ensure full compatibility with mainframes that may have blanking keys inserted. I have accommodated for all Tek specified key locations that I could find. Also the manual has been updated with info on setting the rotary switch to a 4P6T configuration. Some relatively critical info I completely forgot to add previously. All going well, this should be the last revision. I'll be sure to provide Larry with the final files directly just before the order is made to ensure we all get the correct parts without any problems. |
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Re: Slightly OT: How can I dissolve Potting Compound?
On Sat, Jan 2, 2021 at 08:38 PM, Jim Ford wrote:
Gasoline is worse, but... MEK is listed as a precursor... but a lot of industrial chemicals are precursors... and despite being listed... it produced, and used in vast quantities, in the U.S. Model airplane "glue" (actually solvent welding, not gluing) has it, plumbing "glue" has it (dido of welding plastic pipe)... it's used in a lot of products sold to the public. If plumbers and kids can handle it... well... It's not "particularly good" at dissolving the black epoxy potting compound, after it's cured... but, depends which epoxy was used... and given a long time... it might dissolve it. Acetone works better. (But, don't tell your wife of the horrors... or she might have nightmares after she does her nails.) |
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Re: Slightly OT: How can I dissolve Potting Compound?
My first experience with MEK was in early 1966 in the Navy,I spilled some on my belly, It burned like fire, buy the time
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I got my pants down to wash it off it was gone, just a patch of very white skin that was very tender.I never messed with MEK again. I wonder if that had anything to do? with my having Kidney cancer in my right kidney in 2010. To stay on topic many Laser power supplies were potted with a soft and flow able epoxy that was vacuum impregnated and sealed with a hard black epoxy, I used to work for one of Lased Drive's competitors.Try grinding off one corner of the case and pry it up and see what is inside. Leon Robinson ?? K5JLR Political Correctness is a Political Disease. Politicians and Diapers should be changed often and for the same reasons. On Saturday, January 2, 2021, 10:38:48 PM CST, Jim Ford <james.ford@...> wrote:
MEK is really nasty stuff and a precursor to methamphetamine, from what I understand.? A funny but horrifying story about MEK came from a coworker.? Seems a coworker of his years ago wanted some of the used MEK to clean engine parts.? His boss signed off on a 55 gallon drum of the stuff, which he put in the back of his pickup truck.? On down the road, it started leaking onto the highway, which caught the attention of a state trooper!? Not only was he dripping MEK, but he had crossed the state line and had some serious explaining to do!? He and his boss got fired in short order.? ?Moral of the story is be very careful if you're going to use MEK.? IIRC, MEK is flammable and carcinogenic.? ? ?Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone -------- 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" |
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Re: Slightly OT: How can I dissolve Potting Compound?
Hi Dennis:
If it is some kind of epoxy, then acetone dissolves it better then MEK. Cured epoxy resins, like moulded parts, can be exposed to MEK... and show "fair" resistance. (MEK will eventually damage the part.) Exposure to acetone is "not recommended." Using either one... you'll have to immerse... and leave it in soak. As for the results... mileage will vary, according to what's inside (other resin parts/plastic parts might get attacked/dissolved too) ; so, there may be damage. Usually, what is left is enough of an indication to understand what was there; but, the damage may be so that repairing it is not possible. (If there is a pcb inside, you can usually trace that out.) Careful with acetone. It has a low flash point... but, is less toxic than MEK. |
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Re: Slightly OT: How can I dissolve Potting Compound?
MEK is really nasty stuff and a precursor to methamphetamine, from what I understand.? A funny but horrifying story about MEK came from a coworker.? Seems a coworker of his years ago wanted some of the used MEK to clean engine parts.? His boss signed off on a 55 gallon drum of the stuff, which he put in the back of his pickup truck.? On down the road, it started leaking onto the highway, which caught the attention of a state trooper!? Not only was he dripping MEK, but he had crossed the state line and had some serious explaining to do!? He and his boss got fired in short order.? ?Moral of the story is be very careful if you're going to use MEK.? IIRC, MEK is flammable and carcinogenic.? ? ?Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
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-------- 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"
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
On Sat, Jan 2, 2021 at 07:05 PM, Larry McDavid wrote:
Please include me in the list as "JF" since I meet the above qualification as, not identified by full name and some limitation. I'll send you and email now so you know who I am. Thank you sir. |
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Re: Slightly OT: How can I dissolve Potting Compound?
If the heat gun can melt epoxy resins, it may be hot enough to melt other
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plastics - like the insulation on wires (unless it's Teflon or silicone - which it may be in an HV supply). There are quite a few spectral lamp power supplies on eBay (some show up under "arc lamp power supply", but most I would call questionable. One shown operating with a lamp is the most expensive. Likely not worth taking a chance on the others but you could take a look. Steve H. On Sat, Jan 2, 2021 at 10:08 PM EJP <esmond.pitt@...> wrote:
On Sun, Jan 3, 2021 at 01:24 PM, Vince Vielhaber wrote:A heat gun is often the method for removing the potting, but care mustIt is also extremely smelly. Work outdoors or with fume exraction, or at |
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Re: Slightly OT: How can I dissolve Potting Compound?
Breaking down epoxies at room temperature has often come up here and in the hpagilent group. My standard answer is Dimethylformamide, but other solvents can do it too. It's a messy process and some internal parts may get damaged or lose their identity. I think it would be cheaper and cleaner to just get a fresh HeNe driver in the same size class as the original (probably for standard 1 mW HeNe). These used to be commodity items, and I would think used or NOS ones ought to be available cheap since HeNe lasers aren't used so much anymore.
As I recall, the ones I have are labeled something around 2-2.5 kV at 6-15 ma running, depending on tube size, with ignition voltage up to around 10-12 kV. I can't recall the ballast resistor size, but think around 75 kohms, 5W is typical. If your other driver is too big for the discharge tubes you have, you can up the ballast resistance. Also, the driver boxes usually have auto-ignition, so if it doesn't see approximately the normal HeNe load, it will re-strike maybe up to ten times a second, thinking the tube isn't lit. This could be the apparent stability problem you see. All these things can be fixed externally, but it's simplest to get the small kind that you had working already. Ed |
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Re: Slightly OT: How can I dissolve Potting Compound?
On Sun, Jan 3, 2021 at 01:24 PM, Vince Vielhaber wrote:
A heat gun is often the method for removing the potting, but care mustIt is also extremely smelly. Work outdoors or with fume exraction, or at least seriously good ventilation. EJP |
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Folks, a surprising number of you have asked to be included in a group purchase of the sets of four boards for this tester that Jared Cabot developed. I'm keeping a list of those who committed to the purchase and I have these in my list:
ML PA SM DC HB GL MH JR WR JT EW RD AW SG DS MU PE SC LM Those 19 above have identified themselves and not indicated any question or qualification to participating. But, there are others who either did not identify by full name or expressed some qualification or limitation. I recognize these: AA PD S? MP A? B? BO And, two additional with fully cryptic email addresses to whom I sent an email asking for full identity, but with no response. So, there are nine more who may, or may not, commit to the purchase. Please, each of these nine contact me with clarification. If you reply, please be sure your email includes your full name. Later I will need full postal shipping address. Jared has asked for a price quote for sets of three boards from a supplier of his choosing; we'll know that quote next week. For USA buyers, I can determine a packaging and shipping cost. With so many sets to be ordered, I must have payment in advance of ordering the boards. PayPal Friends and Family is an easy way to do this; if you object to that, we can talk about it. Jared is located in Japan and cannot practically offer these board sets himself. I, with Jared's help, can place the order and redistribute the board sets. I will not provide any other parts, including the rotary switch, which I now note is available from DigiKey. Jared below suggests an approximate board set cost but packaging and postage must be added to that. My preference is to ship by USPS Priority Mail; with packaging in an appropriate box, that might add $10 as an estimate. I'm a bit surprised at the number who want to build this TM500 tester. I'll reply again when I know more. Larry On 1/1/2021 10:31 PM, Jared Cabot via groups.io wrote: On Sat, Jan 2, 2021 at 06:29 AM, Larry McDavid wrote:...One small addendum to this, the PCB's will likely not be black as that is a premium option that adds significant cost. They will most likely come in the usual green (more period accurate! :) ) to save as much on cost as possible. -- Best wishes, Larry McDavid W6FUB Anaheim, California (SE of Los Angeles, near Disneyland) |
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Re: Grid Bias Adjustment on 475A
So I've measured everything EXCEPT the high voltage levels (waiting on an HV probe).
R1396 and R1399 feed the second grid on pin #8, the schematic says they should see +50 V, and I measured +50 V R1398 feeds the astigmatism grid, schematic says the range should be -8 V to +110 V, I see that range, the original setting was +40.82 V R1330, R1329, VR1329, C1329, and CR1329 feed the mesh and all meet at a node on one of the ceramic terminals, according to the schematic that node is supposed to be -150 V, but I measure -110 V. The -150V level is supposed to have (if I am reading the schematic correctly) a sine wave superimposed with a range of 300 mV peak to peak, but what I see when I hook the scope up to the common node on the ceramic terminal (rather than the opposite side of CR1329, which I think is high voltage) is only 150 mV peak to peak, and not very sinusoidal. So the mesh voltage is low (high?) and its AC signal looks wrong. Maybe one or more of the passive components is failed (which I can check pretty easily, with the power off, by lifting the legs attached to the ceramic terminal), but it might also be a problem with T1320, which I guess is on the opposite side of the board? I have an HV multimeter probe coming on Tuesday, so I'll feel better about checking the high voltage stuff then. I don't really understand what the mesh is doing in this CRT. Is the mesh bias really a good candidate for the symptom I'm seeing? -- Jeff Dutky |
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Re: Slightly OT: How can I dissolve Potting Compound?
You can try MEK, methyl ethyl keytone.
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It will dissolve a lot of epoxies. Be careful to not dissolve other things. 73 Glenn WB4UIV On 1/2/2021 9:18 PM, Dennis Tillman W7pF wrote:
I need to dissolve the black HV potting compound of a 12VDC powered --
----------------------------------------------------------------------- Glenn Little ARRL Technical Specialist QCWA LM 28417 Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178 QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR "It is not the class of license that the Amateur holds but the class of the Amateur that holds the license" |
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Re: Slightly OT: How can I dissolve Potting Compound?
A heat gun is often the method for removing the potting, but care must be taken since some of the potting compounds get very toxic with heat.
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Is there a model number on the dead supply? Vince. On 01/02/2021 09:18 PM, Dennis Tillman W7pF wrote:
I need to dissolve the black HV potting compound of a 12VDC powered --
K8ZW |
Dave Peterson
Jared Cabot
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