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hondgm@yahoo.com: Oct 08 06:55PM -0700 I have this old fluorescent desk lamp from the 60s at the latest that I'm fixing. It weighs a ton, has been passed down from my father-in-law, and it just retro-cool. According to him it's always worked, except the F15-T8 bulbs are possibly original and very worn out, and only one bulb ever lights. I've been told this has always been a problem, and holding the start button for a long time will sometimes get both to start. I've never been successful but I don't like this and want to fix it.   Upon reverse engineering it I come up with this schematic (it's rough, drawn in Paint!):     https://imgur.com/a/0YYKV   I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?   If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.   I'm a little surprised to see some that seems this hokey (to me) in something this old.

Tom Biasi <tombiasi@optonline.net>: Oct 08 10:56PM -0400 > I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?   > If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.   > I'm a little surprised to see some that seems this hokey (to me) in something this old.   Check connections and/or new tubes new ballasts.

Rheilly Phoull <rheilly@bigslong.com>: Oct 09 02:09PM +0800 > I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?   > If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.   > I'm a little surprised to see some that seems this hokey (to me) in something this old.   Like Tom said also change the tubes over and see if its the one tube U/s

John Robertson <spam@flippers.com>: Oct 08 11:28PM -0700 > I have this old fluorescent desk lamp from the 60s at the latest that I'm fixing. It weighs a ton, has been passed down from my father-in-law, and it just retro-cool. According to him it's always worked, except the F15-T8 bulbs are possibly original and very worn out, and only one bulb ever lights. I've been told this has always been a problem, and holding the start button for a long time will sometimes get both to start. I've never been successful but I don't like this and want to fix it.   > Upon reverse engineering it I come up with this schematic (it's rough, drawn in Paint!):   > https://imgur.com/a/0YYKV   Normal old style start circuit where a 'starter' is not used. This circuit is found on desk/counter fluorescent lights where you pushed a button to light the tube, after holding the button for a second or two. Button switch is momentary on.     > I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?   The bulbs are independent of each other (even though the start windings are shorted together for starting) - each has a ballast. I would expect that the tube that doesn't light has a bad ballast. Did you exchange the bulbs to see if the good one lights in the other position? It may also be that the tube connector pins are bent or a broken connection. Use an ohm-meter to check continuity with only one bulb installed at a time.     > If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.   > I'm a little surprised to see some that seems this hokey (to me) in something this old.   This light was just after WWII is my guess, and starters were not always used.   If you need a 15watt ballast they are around $10US - you want the two-wire version. We use these in jukeboxes and arcade games.   John :-#)#   -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."

tabbypurr@gmail.com: Oct 09 01:58AM -0700 > I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?   > If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.   > I'm a little surprised to see some that seems this hokey (to me) in something this old.   The circuit is a right bodge. The 2 tubes are connected in parallel, the lit one will be taking around twice its rated run current.     NT

hondgm@yahoo.com: Oct 09 04:29AM -0700 I should clarify a few things.   -I already purchased new bulbs. The old ones worked but were very dim.   -The ballasts each measure about 30 ohms. I have not yet put an inductance meter on them but my guess is they are good.   -I connected the bulbs using jumper wires to eliminate bad connections in the sockets. No change.   -If I install only one bulb with everything wired as it originally was, that one always starts. If I remove it and install the other bulb in the other bulb socket pair, that one also always starts. With both in circuit, I've never seen them both start, only one does.   -With both bulbs in circuit one specific bulb tends to start, but randomly the other does instead.   -If I separate out each bulb-ballast circuit so they look like completely independent fixtures and start each manually by temporarily shorting the one bulb pin at each end, each starts and runs no problem. So that's why I believe both ballasts are good.   The part of the original circuit I'm having trouble dealing with is how the bulbs are permanently connected at the same end as the ballast connection. It seems one bulb could steal the start pulse from both ballasts, hence the reason for the issue. But then again this was designed this way and supposedly would work?   I have a DPDT relay on the way to isolate each starting switch and that will fix it, but did these desk lamps ever intend to work correctly? Seems odd.

Chris Jones <lugnut808@spam.yahoo.com>: Oct 09 03:17PM +1100 On 07/10/2017 00:00, Tim R wrote: > The neighbor has a Sharp LCD tv, small screen size but rather thick profile, with a cracked screen.   > The glass in front isn't cracked but if you turn it on there's a nice pattern of cracks radiating out from what looks like a small impact site.   > We're trying to figure out how to dispose of it without paying the recycling fee. It's $25 per unit for electronics here. Would there be any components in it worth salvaging? I dunno, power supply, memory, something like that?   You could try looking on e-bay to see whether others have successfully sold any of the PCBs with the same part numbers on them. Perhaps selling a couple of the boards would get you nearly enough to pay for the disposal fee for the rest of it.

"Michael A. Terrell" <mike.terrell@earthlink.net>: Oct 08 08:04PM -0400 > i) The cats and dogs are also healthy - the cats are both more intelligent than the average Republican as well, and I have the T-Shirt to prove it. The dogs are simply better than the average Republican. > j) I sleep well and peacefully.   > tRump has nothing I want, nothing I would aspire to wanting, and has done nothing that catches my imagination or admiration. Clearly he lives an unhappy, frightened and tiny little world as proven by his tweets, choice of language, bullying behavior and pathological fascination with "winning". I wonder when he last got a good night's sleep, or if he will get one ever again in the future.     Yawnnnnnnnnnnnnnnnnnnnnnn...     -- Never piss off an Engineer!   They don't get mad.   They don't get even.   They go for over unity! ;-)

"Michael A. Terrell" <mike.terrell@earthlink.net>: Oct 08 08:06PM -0400 Trevor Wilson wrote:   > **Do you mean: > How many millions did I inherit from my father?     It was one million to invest in real estate. Do some research.     -- Never piss off an Engineer!   They don't get mad.   They don't get even.   They go for over unity! ;-)

"Michael A. Terrell" <mike.terrell@earthlink.net>: Oct 08 08:09PM -0400 Foxs Mercantile wrote:   > You're wasting your breath on this one. > Michael has spent the entire 8 years of President Obama bitching about > "That Nigger in the White House."   Liar.I never called him that. I've never called anyone that.   > And replaying all the usual claptrap from the Right Wing echo chamber.   And you were bragging about the worthless 'Democrat' candidates, Clinton and Sanders. That was why I unfriended you and your wife on Facebook.     -- Never piss off an Engineer!   They don't get mad.   They don't get even.   They go for over unity! ;-)

Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au>: Oct 09 11:46AM +1100 On 9/10/2017 11:06 AM, Michael A. Terrell wrote:   >> **Do you mean: >> How many millions did I inherit from my father?   > It was one million to invest in real estate. Do some research.   **A million Buck in 1976 Dollars would be a very substantial amount in today's money. Moreover, Trump's father either directly loaned money to his son, or guaranteed loans to Trump. None of which is easy for the vast majority of Americans to obtain. Trump got it easy. VERY easy. In fact, back in 1974, my father offered to loan me $1,000.00 so I could buy my second car. He then said, that a loan form him was to be a last resort and that I should go to the bank and borrow my own money. I did so. Trump, by comparison received 1,000 times that amount from his father.   -- Trevor Wilson www.rageaudio.com.au

Foxs Mercantile <jdangus@att.net>: Oct 08 10:11PM -0500 On 10/8/2017 7:09 PM, Michael A. Terrell wrote: >> Michael has spent the entire 8 years of President Obama bitching >> about "That Nigger in the White House."   >    Liar.I never called him that. I've never called anyone that.   Uh huh, "He said, she said." You parroted every conspiracy theory from the GOP echo chamber   > And you were bragging about the worthless 'Democrat' candidates, > Clinton and Sanders.   And we're supposed to be impressed by the moron you voted for?   > That was why I unfriended you and your wife on Facebook.   Good riddance.     -- Jeff-1.0 wa6fwi http://www.foxsmercantile.com

"fynnashba@yahoo.com" <fynnashba@yahoo.com>: Oct 08 11:53AM -0700 please can anyone show me how to calculate the base resistor for an NPN transistor used as a switch. the supply voltage is 12 volts, the load is a 12 volts relay with a resistance of 300 Ohms. thank you.

nobody@nowhere.invalid (natp): Oct 08 08:12PM >please can anyone show me how to calculate the base resistor for an NPN transistor used as a switch. the supply voltage is 12 volts, the load is a 12 volts relay with a resistance of 300 Ohms. >thank you.   When the NPN transistor is saturated (fully on), the emitter-collector voltage will be about 0.2-0.3 volts. Using the other values you have, you can calculate Ic; the current flowing through the collector (and the relay).   To saturate the transistor, the base current must be greater than Ic / beta where "beta" is the minimum current gain of the transistor.   The last piece of information you need is that the base-emitter voltage is one "diode-drop"; about 0.7 volts.

mike <ham789@netzero.net>: Oct 08 01:33PM -0700 On 10/8/2017 1:12 PM, natp wrote: > where "beta" is the minimum current gain of the transistor.   > The last piece of information you need is that the base-emitter > voltage is one "diode-drop"; about 0.7 volts.   It's customary to overdrive the base. I normally use a factor of 10. It's also customary to put a reverse diode across the coil so that the turn-off transient doesn't overvoltage the collector.

tabbypurr@gmail.com: Oct 08 02:00PM -0700 > please can anyone show me how to calculate the base resistor for an NPN transistor used as a switch. the supply voltage is 12 volts, the load is a 12 volts relay with a resistance of 300 Ohms. > thank you.   12v 300ohms is 40mA. Assume beta of at least 30, so we need 40/30mA into the base = 1.3mA V across base R is 12v - 0.7v = 11.3v R=V/I so R = 11.3/1.3m = 8.5k. Preferred values below that to give a bit more i are 8k2 or 6k8 or 4k7.     NT

"fynnashba@yahoo.com" <fynnashba@yahoo.com>: Oct 08 02:03PM -0700 > please can anyone show me how to calculate the base resistor for an NPN transistor used as a switch. the supply voltage is 12 volts, the load is a 12 volts relay with a resistance of 300 Ohms. > thank you.   Thanks all your suggestion are well taken

Clifford Heath <no.spam@please.net>: Oct 09 11:52AM +1100 On 09/10/17 07:33, mike wrote: >> voltage is one "diode-drop"; about 0.7 volts.   > It's customary to overdrive the base.  I normally use a factor of > 10.   Beta is reduced near saturation. 10x is an attempt to compensate.

"Dave M" <dgminala@mediacombb.net>: Oct 08 03:40PM -0500 Anyone have any experience or have colleagues who have experience using the Chinese-made reflow soldering ovens such as those being sold on the evil auction place? The one I've looked at is item number:262955348183 (Model T962).   My eyes have become the major challenge to producing the one- or two-off projects, since many of the parts that are available today are only made in SMD packages. I realize that placing them onto the board still remains a challenge, but at least with a proper oven, I won't have to hold a soldering iron steady enough to build the boards.   This model seems to be big enough to handle all the boards that I want to make, so that is a plus. Just wondering if this model produces good boards with no unsoldered areas, damaged components, etc. If it can consistently produce good boards, I'll take a chance on one of them. Reading the Chinglish instructions is scary enough , but maybe I can figure it out well enough to make it work.   Hope someone can give good advice   Dave M

Jeff Liebermann <jeffl@cruzio.com>: Oct 08 02:17PM -0700 On Sun, 8 Oct 2017 15:40:58 -0500, "Dave M" <dgminala@mediacombb.net> wrote:   >SMD packages. I realize that placing them onto the board still remains a >challenge, but at least with a proper oven, I won't have to hold a soldering >iron steady enough to build the boards.   With solder paste, if you misalign the component slightly, when the solder reflows, it will magically float into the proper position.   >Hope someone can give good advice   If you Google for "toaster oven reflow contoller": <https://www.google.com/search?q=toaster+oven+reflow+controller> You'll find a variety of articles on how to modify a toaster oven into a workable reflow oven. For example, here's a list of possible kits: <https://www.eevblog.com/forum/reviews/favorite-diy-reflow-toaster-oven-controllers/> Here's my version which I use mostly to reflow chronically defective HP Jetdirect network cards: <http://802.11junk.com/jeffl/pics/repair/BGA%20reflow/index.html>     -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

Gerhard Hoffmann <gerhard@hoffmann-hochfrequenz.de>: Oct 08 11:26PM +0200 Am 08.10.2017 um 22:40 schrieb Dave M: > Chinglish instructions is scary enough , but maybe I can figure it out well > enough to make it work.   > Hope someone can give good advice   I have one of these:   < https://eleshop.eu/vapour-phase-mini-condens-it.html >   Bought it when the manufacturer did not yet have distributors, at a somewhat smaller price.   Vapor phase is a completely different game.       I'm still trying to recover from the "English manuals" of < http://www.ebay.de/itm/112168145773?ul_noapp=true >, which is a Locky_Z curve tracer:   I got some results for JFETs:   Some IF3602 pairs: < https://www.flickr.com/photos/137684711@N07/37321004540/in/dateposted-public/   Some of the new ones from ON, e.a.: < https://www.flickr.com/photos/137684711@N07/36909661793/in/dateposted-public/   I had no luck so far with 2N2222. Probably they oscillate happily on the tracer and need base stoppers.     cheers, Gerhard

Neon John <no@never.com>: Oct 08 05:54PM -0400 On Sun, 8 Oct 2017 15:40:58 -0500, "Dave M" <dgminala@mediacombb.net> wrote:   >Chinese-made reflow soldering ovens such as those being sold on the evil >auction place? The one I've looked at is item number:262955348183 (Model >T962).   My concern (mainly because I have no experience with infrared) is that the black chips and components would get hot faster than the shiny pins and solder paste.   I have an oven that I built using a tabletop convection oven and a programmable timer. It works great but it's using hot air to do the heating. >SMD packages. I realize that placing them onto the board still remains a >challenge, but at least with a proper oven, I won't have to hold a soldering >iron steady enough to build the boards.   The neat thing about reflow is that if you put the proper amount of paste on each pad, the surface tension of the solder will pull the part or chip in line with the pads.   I've developed an unconventional technique for pasting 0.5 mm pin spaced ICs. I put the chip on its back and use my pressure/vacuum paste dispenser to lay a solid stream across each side of the chip.   I then hold the chip with some pliers while I wipe the other side with a Q-tip. This removes paste between the pins. Drop the chip in place, populate the rest of the board and reflow. Both my vision and my steadiness of hand have declined over the past few years and this is how I compensated. >produce good boards, I'll take a chance on one of them. Reading the >Chinglish instructions is scary enough , but maybe I can figure it out well >enough to make it work.   That thing is cheap enough that if I didn't already have an oven, I'd buy one just to test it. It would hurt only a little to bin it if it didn't work.   John   John DeArmond http://www.neon-john.com http://www.tnduction.com Tellico Plains, Occupied TN See website for email address

Jeff Liebermann <jeffl@cruzio.com>: Oct 08 03:37PM -0700 On Sun, 8 Oct 2017 15:40:58 -0500, "Dave M" <dgminala@mediacombb.net> wrote:   >Chinese-made reflow soldering ovens such as those being sold on the evil >auction place? The one I've looked at is item number:262955348183 (Model >T962).   Original Chinese web page: <http://www.tech168.cn/a/chanpinzhanshi/huiliuhanji/2013110256.html> Looks like it's still in production.   T962A SMD Reflow Oven Fix/Hack <http://www.instructables.com/id/T962A-SMD-Reflow-Oven-FixHack/>   Maintaining a list of T962/T962A problems, improvements and suggestions how to get good results #76 <https://github.com/UnifiedEngineering/T-962-improvements/issues/76>   Modifying the T-962 Reflow Oven <https://www.youtube.com/watch?v=0ITZXY5Mipc>   More videos: <https://www.youtube.com/watch?v=EMwRdEi0iPg> <https://www.youtube.com/watch?v=zj1qn476k9o> <https://www.youtube.com/watch?v=IgPMvaY8ibQ> <https://www.youtube.com/watch?v=JH8Qd1vv768> <https://www.youtube.com/watch?v=cP2SYn7XFl4>     -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

John Larkin <jjlarkin@highlandtechnology.com>: Oct 08 03:44PM -0700 On Sun, 8 Oct 2017 15:40:58 -0500, "Dave M" <dgminala@mediacombb.net> wrote:   >SMD packages. I realize that placing them onto the board still remains a >challenge, but at least with a proper oven, I won't have to hold a soldering >iron steady enough to build the boards.   My vision has always been mediocre, and it's not improving with age. (The retina detach didn't help, either, but that's mostly fixed now.) I got a compact Mantis on ebay and it totally changed my attitude about SMT. I was replacing some 0603 resistors yesterday and the optics was no problem.   https://www.dropbox.com/s/wlim2da8cv9q6fj/Bench_Mantis.jpg?raw=1   https://www.dropbox.com/s/fp88o2rqgr87g9d/Mantis2.JPG?raw=1   The imaging is startling, and there's enough working distance for soldering or probing. Or Dremeling.   https://www.dropbox.com/s/7bihbjbaojvta0z/Z382_1.JPG?raw=1   When you can really see what you are doing, steadiness improves too.   As people have noted, a convection oven may be all you need for reflow.     --   John Larkin Highland Technology, Inc   lunatic fringe electronics

"fynnashba@yahoo.com" <fynnashba@yahoo.com>: Oct 08 12:17PM -0700 please comrades, where can i get a good book on pal Tv for a radio and TV intermediate course?(11th to 13th grade) A second book on radio communication will also help.

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