---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 07/15/04: 31 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:07 AM - Re: Solder - Rosin-core or paste flux (KITFOXZ@aol.com) 2. 05:19 AM - Re: Solder - Rosin-core or paste flux (BobsV35B@aol.com) 3. 06:48 AM - Re: Solder - Rosin-core or paste flux (erie) 4. 07:18 AM - Crimp tool for King connectors? (Peter Mather) 5. 07:18 AM - Crimp tool for King connectors? (Peter Mather) 6. 08:26 AM - Re: Solder - Rosin-core or paste flux (Robert L. Nuckolls, III) 7. 08:26 AM - Re: Solder - Rosin-core or paste flux (echristley@nc.rr.com) 8. 08:39 AM - Re: Solder - Rosin-core or paste flux (echristley@nc.rr.com) 9. 08:57 AM - Cabin speaker specs (Ralph E. Capen) 10. 09:14 AM - Re: Crimp tool for King connectors? (James Redmon) 11. 10:03 AM - Re: Cabin speaker specs (James Foerster) 12. 10:06 AM - Re: Cabin speaker specs (Robert L. Nuckolls, III) 13. 10:29 AM - Re: Re: Cabin speaker specs (Ralph E. Capen) 14. 10:33 AM - Re: Cabin speaker specs (Ralph E. Capen) 15. 11:03 AM - Re: Re: Cabin speaker specs (Paul Messinger) 16. 11:15 AM - Re: Re: Cabin speaker specs (Ralph E. Capen) 17. 12:05 PM - Re: Re: Cabin speaker specs (Matt Prather) 18. 12:16 PM - Re: Re: Avionics Master Switch (Brian Lloyd) 19. 01:35 PM - Re: Re: Avionics Master Switch (Paul Messinger) 20. 01:35 PM - Re: Re: Cabin speaker specs (Paul Messinger) 21. 01:50 PM - Re: Re: Cabin speaker specs (Brian Lloyd) 22. 02:04 PM - Re: Cabin speaker specs (Fiveonepw@aol.com) 23. 02:19 PM - Re: Re: Cabin speaker specs (Matt Prather) 24. 02:44 PM - Re: Re: Avionics Master Switch (Brian Lloyd) 25. 03:29 PM - Turn Coordinator () 26. 04:27 PM - Re: Re: Avionics Master Switch (Matt Prather) 27. 06:16 PM - The maintenance officer says we have had several radios fried by (Rex & Jan Shaw) 28. 06:47 PM - Re: Solder - Rosin-core or paste flux (KITFOXZ@aol.com) 29. 06:54 PM - Re: Solder - Rosin-core or paste flux (KITFOXZ@aol.com) 30. 07:36 PM - LED experiment (Ernest Christley) 31. 10:15 PM - Re: LED experiment (David Carter) ________________________________ Message 1 _____________________________________ Time: 05:07:55 AM PST US From: KITFOXZ@aol.com Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux --> AeroElectric-List message posted by: KITFOXZ@aol.com In a message dated 7/14/2004 9:29:28 PM Eastern Standard Time, kjashton@vnet.net writes: Bob, I found it helpful to put a touch of liquid flux on the ends of those 25 pin D-sub connectors prior to soldering AWG 22 wires in them. Seemed to make them go together better. Otherwise I agree. --Kent 3 aircraft wired per Aeroelectric Connection Bob, Kent, Yes, I was taught to do this by the US Navy in the early seventies. A little liquid flux on small pins or parts helps to speed up the whole soldering process and definitely helps to accomplish that perfect shiny, smooth finish. The heat transfers to the work piece faster and the liquid flux cleans the soldering iron tip and the wire/pin, etc., at that last second to ensure a cleaner joint. I urge all doubters to try this: Solder a few wires into a D-sub connector your own way and then try it this way: Strip a few wires for use and prepare to solder by dipping the stripped ends in liquid flux. Clean the soldering iron tip on a wet sponge and freshly tin with solder. Tin the iron tip with just a little more solder than needed and then immediately touch the stripped and fluxed wire end to the iron tip for a second. The wire end will wick the solder up in that first second to just the right fill with no extra that tends to thicken the wire's cross section. Cut the wire's stripped and tinned end to ideal length for insertion into the solder cup of the pin on your connector. Now is the time to clean the flux off the wire and add the wire sleeve or heat shrink tubing (especially if the other end of your wire is already terminated). With the D-sub connector held in a clamp on the bench, apply a little liquid flux to the solder cup of a pin and touch the soldering iron tip to it as above in the wire prep stage. The iron needs to be freshly cleaned and tinned immediately before this step. The cup will take up the solder and should be about half full for best results. You can add some solder but don't bother because the cup does not have to be full for a very good joint to result. Now you have a tinned wire and a tinned solder cup on your connector pin and the perfect joint is about to happen! Put a drop of liquid flux in the tinned solder cup. Hold the wire end to the solder cup of the pin and again touch the again freshly cleaned and tinned iron tip to them as you push the wire home and remove the iron in less than a second. The cup will be full or nearly so and the wire end will be embedded in a nice shiny, smooth fillet of solder. Slide the sleeve or heat shrink home after you have cleaned the flux off. Don't burn your fingers. John P. Marzluf Columbus, Ohio Kitfox Outback (out back in the garage) ________________________________ Message 2 _____________________________________ Time: 05:19:55 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux --> AeroElectric-List message posted by: BobsV35B@aol.com In a message dated 7/15/04 7:08:49 AM Central Daylight Time, KITFOXZ@aol.com writes: Yes, I was taught to do this by the US Navy in the early seventies. A little liquid flux on small pins or parts helps to speed up the whole soldering process and definitely helps to accomplish that perfect shiny, smooth finish. The heat transfers to the work piece faster and the liquid flux cleans the soldering iron tip and the wire/pin, etc., at that last second to ensure a cleaner joint. Good Morning John, Thanks for the great description. Do you have any specific recommendations as to types or brands of flux or solder? Happy Skies, Old Bob AKA Bob Siegfried Ancient Aviator Stearman N3977A Brookeridge Airpark LL22 Downers Grove, IL 60516 630 985-8502 ________________________________ Message 3 _____________________________________ Time: 06:48:27 AM PST US From: erie Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux --> AeroElectric-List message posted by: erie If I'm not mistaken, soldering introduces a stress riser where the solder ends, so cable clamping in the shell becomes critical to long term survival, Crimping, on the other hand, when properly done makes a gas tight joint that survives better in a high vibration environment. erie Kent Ashton wrote: >--> AeroElectric-List message posted by: Kent Ashton > >Bob, I found it helpful to put a touch of liquid flux on the ends of those >25 pin D-sub connectors prior to soldering AWG 22 wires in them. Seemed to >make them go together better. Otherwise I agree. >--Kent >3 aircraft wired per Aeroelectric Connection > > ________________________________ Message 4 _____________________________________ Time: 07:18:31 AM PST US From: "Peter Mather" Subject: AeroElectric-List: Crimp tool for King connectors? --> AeroElectric-List message posted by: "Peter Mather" I'd appreciate advice on the best crimp tool to use for the connectors as used by Bendix-King on their units (KX155 etc.) also where best to buy one. Many thanks Peter ________________________________ Message 5 _____________________________________ Time: 07:18:31 AM PST US From: "Peter Mather" Subject: AeroElectric-List: Crimp tool for King connectors? --> AeroElectric-List message posted by: "Peter Mather" I'd appreciate advice on the best crimp tool to use for the connectors as used by Bendix-King on their units (KX155 etc.) also where best to buy one. Many thanks Peter ________________________________ Message 6 _____________________________________ Time: 08:26:22 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:47 AM 7/15/2004 -0500, you wrote: >--> AeroElectric-List message posted by: erie > >If I'm not mistaken, soldering introduces a stress riser where the >solder ends, so cable clamping in the shell becomes critical to long >term survival, >Crimping, on the other hand, when properly done makes a gas tight joint >that survives better in a high vibration environment. > >erie There is no functional differences and/or advantages of crimp over solder. See: http://www.aeroelectric.com/articles/terminal.pdf http://www.aeroelectric.com/articles/rules/review.html http://www.aeroelectric.com/articles/CrimpTools/crimptools.html Both produce "stress risers" both produce "gas tight" joints. One process takes skill to use low cost tools, the other requires high cost tools and more expensive materials to offset a need for experience and skills. Either technique can produce very satisfactory, long lived connections. Bob . . . ________________________________ Message 7 _____________________________________ Time: 08:26:38 AM PST US From: echristley@nc.rr.com Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux --> AeroElectric-List message posted by: echristley@nc.rr.com ----- Original Message ----- From: KITFOXZ@aol.com Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux > --> AeroElectric-List message posted by: KITFOXZ@aol.com > > > In a message dated 7/14/2004 9:29:28 PM Eastern Standard Time, > kjashton@vnet.net writes: > > Bob, I found it helpful to put a touch of liquid flux on the ends > of those > 25 pin D-sub connectors prior to soldering AWG 22 wires in them. > Seemed to > make them go together better. Otherwise I agree. > --Kent > 3 aircraft wired per Aeroelectric Connection > > > Bob, Kent, > > Yes, I was taught to do this by the US Navy in the early > seventies. A > little liquid flux on small pins or parts helps to speed up the > whole soldering > process and definitely helps to accomplish that perfect shiny, > smooth finish. > The heat transfers to the work piece faster and the liquid flux > cleans the > soldering iron tip and the wire/pin, etc., at that last second to > ensure a > cleaner joint. > > I urge all doubters to try this: Solder a few wires into a D-sub > connector > your own way and then try it this way: Strip a few wires for use > and prepare > to solder by dipping the stripped ends in liquid flux. Clean the > soldering > iron tip on a wet sponge and freshly tin with solder. Tin the > iron tip with > just a little more solder than needed and then immediately touch > the stripped > and fluxed wire end to the iron tip for a second. The wire end > will wick the > solder up in that first second to just the right fill with no > extra that > tends to thicken the wire's cross section. Cut the wire's > stripped and tinned > end to ideal length for insertion into the solder cup of the pin > on your > connector. Now is the time to clean the flux off the wire and add > the wire sleeve > or heat shrink tubing (especially if the other end of your wire is > already > terminated). > > With the D-sub connector held in a clamp on the bench, apply a > little liquid > flux to the solder cup of a pin and touch the soldering iron tip > to it as > above in the wire prep stage. The iron needs to be freshly > cleaned and tinned > immediately before this step. The cup will take up the solder and > should be > about half full for best results. You can add some solder but > don't bother > because the cup does not have to be full for a very good joint to > result. > Now you have a tinned wire and a tinned solder cup on your > connector pin and > the perfect joint is about to happen! > > Put a drop of liquid flux in the tinned solder cup. Hold the wire > end to > the solder cup of the pin and again touch the again freshly > cleaned and tinned > iron tip to them as you push the wire home and remove the iron in > less than a > second. The cup will be full or nearly so and the wire end will > be embedded > in a nice shiny, smooth fillet of solder. Slide the sleeve or > heat shrink > home after you have cleaned the flux off. > > Don't burn your fingers. > > John P. Marzluf > Columbus, Ohio > Kitfox Outback (out back in the garage) > Excellent practice for a perfect solder joint, but just one more step will make the job much easier. Thin the flux about 10 to 1 with alcohol. It only takes a minute layer of flux to block out the oxygen that ruins your day, and extra flux just burns and give you more to clean off. As a technician in an AT&T manufacturing plant, I used to put down a 150-pin, surface mount IC in about 30sec without a single bridge. The problem with cored flux is that it doesn't coat the parts until AFTER it is heated...which means that it has already had a chance to oxidize. Keep the thinned flux in a miniature, needle-tipped squeeze bottle and your work will improve ten-fold. ________________________________ Message 8 _____________________________________ Time: 08:39:55 AM PST US From: echristley@nc.rr.com Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux --> AeroElectric-List message posted by: echristley@nc.rr.com ----- Original Message ----- From: richard dudley Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux > --> AeroElectric-List message posted by: richard dudley > > Hi George, > There is a problem with paste flux in any electronic wiring. Its > residue > is corrosive and in time will damage anything metallic it comes in > contact with. Because of this property it is especially risky to > use it > in aircraft wiring. Rosin core is the preferred solder for use in > electronics. > > Regards, > > Richard Dudley > -6A painting Don't use plumber's solder in electronics...EVER. Just as you say, it is corrosive. Electronic solder is not. The problem is the residue is stick and will gunk up everything with conductive goo. The rosin core is no less worrisome than the paste, as it is the exact same material. Clean all your solder joints with alcohol after soldering for two reasons. 1) It removes the sticky goo, and 2) it is the only way to tell if you have a cold solder joint. If it's not bright and shiny, or has what looks like a crack in the middle, then it is very prone to develop high resistance at some point not to far in the future. The solder should be laid down so that you can see the outline of the wire under it. If you've have a glob of solder sticking things together, there is no way to tell what you have under there. It may still work just fine forever, and then again, it may not. ________________________________ Message 9 _____________________________________ Time: 08:57:23 AM PST US From: "Ralph E. Capen" avionics-list@matronics.com Subject: AeroElectric-List: Cabin speaker specs --> AeroElectric-List message posted by: "Ralph E. Capen" Folks, After checking the archives for amplifying (pun intended) information - I have decided that a small cabin speaker would be helpful for ground operation (pre-flight etc). My audio panel instructions call for a 4 ohm speaker which seem to be difficult to locate. 8 ohm speakers are available in abundance..... Will I fry something if I use a 8 ohm speaker? Or will it not work properly - volume, freq, distortion...? Thanks, Ralph Capen ________________________________ Message 10 ____________________________________ Time: 09:14:55 AM PST US From: "James Redmon" Subject: Re: AeroElectric-List: Crimp tool for King connectors? --> AeroElectric-List message posted by: "James Redmon" I used the crimper that B&C sells - it worked great. But, I imagine that any good Molex crimper (.156 pin size) will do the job. James Redmon Berkut #013 N97TX http://www.berkut13.com ----- Original Message ----- From: "Peter Mather" Subject: AeroElectric-List: Crimp tool for King connectors? > --> AeroElectric-List message posted by: "Peter Mather" > > I'd appreciate advice on the best crimp tool to use for > the connectors as used by Bendix-King on their units > (KX155 etc.) also where best to buy one. > > Many thanks > > Peter ________________________________ Message 11 ____________________________________ Time: 10:03:48 AM PST US From: "James Foerster" Subject: AeroElectric-List: Re: Cabin speaker specs --> AeroElectric-List message posted by: "James Foerster" Ralph asked: "After checking the archives for amplifying (pun intended) information - I have decided that a small cabin speaker would be helpful for ground operation (pre-flight etc). My audio panel instructions call for a 4 ohm speaker which seem to be difficult to locate. 8 ohm speakers are available in abundance..... Will I fry something if I use a 8 ohm speaker? Or will it not work properly - volume, freq, distortion...?" Power input to the speaker is V squared divided by R, so you will get 1/2 the power into your 8 ohm speaker compared to the 4 ohm. This is 3 db, hardly noticable. As the load on the amplifier is less, you will hurt nothing. The opposite choice: 4 ohm speaker on an amp rated for 8 ohms, might lead to distortion. You are going in the safe direction by using a speaker with an impedance greater than the "rated" impedance of the amp. Jim Foerster J400, 80%,... ________________________________ Message 12 ____________________________________ Time: 10:06:14 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Cabin speaker specs --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:56 AM 7/15/2004 -0500, you wrote: >--> AeroElectric-List message posted by: "Ralph E. Capen" > > >Folks, > >After checking the archives for amplifying (pun intended) information - I >have decided that a small cabin speaker would be helpful for ground >operation (pre-flight etc). > >My audio panel instructions call for a 4 ohm speaker which seem to be >difficult to locate. 8 ohm speakers are available in abundance..... > >Will I fry something if I use a 8 ohm speaker? Or will it not work >properly - volume, freq, distortion...? > >Thanks, >Ralph Capen The 4-ohm callout on your audio panel is the recommended load for maximum output. If you use an 8-ohm speaker, the maximum output will be 1/2 that of the 4-ohm speaker. This says NOTHING about speaker efficiency . . . there are good 8-ohm devices that would put out more sound pressure than a cheap 4-ohm device. Don't worry about it. An 8-ohm speaker will work just fine for ground ops. If push comes to shove, install two 8-ohm devices side by side and you'll double the sound pressure by taking advantage of the amplifier's rated capabilities . . . but I'm certain that this will not be necessary. Bob . . . --- ________________________________ Message 13 ____________________________________ Time: 10:29:41 AM PST US From: "Ralph E. Capen" Subject: Re: AeroElectric-List: Re: Cabin speaker specs --> AeroElectric-List message posted by: "Ralph E. Capen" Good info - thanks for the tron lesson too! -----Original Message----- From: James Foerster Subject: AeroElectric-List: Re: Cabin speaker specs --> AeroElectric-List message posted by: "James Foerster" Ralph asked: "After checking the archives for amplifying (pun intended) information - I have decided that a small cabin speaker would be helpful for ground operation (pre-flight etc). My audio panel instructions call for a 4 ohm speaker which seem to be difficult to locate. 8 ohm speakers are available in abundance..... Will I fry something if I use a 8 ohm speaker? Or will it not work properly - volume, freq, distortion...?" Power input to the speaker is V squared divided by R, so you will get 1/2 the power into your 8 ohm speaker compared to the 4 ohm. This is 3 db, hardly noticable. As the load on the amplifier is less, you will hurt nothing. The opposite choice: 4 ohm speaker on an amp rated for 8 ohms, might lead to distortion. You are going in the safe direction by using a speaker with an impedance greater than the "rated" impedance of the amp. Jim Foerster J400, 80%,... ________________________________ Message 14 ____________________________________ Time: 10:33:34 AM PST US From: "Ralph E. Capen" Subject: Re: AeroElectric-List: Cabin speaker specs --> AeroElectric-List message posted by: "Ralph E. Capen" Thanks Bob, This will probably be the way that I go as there are small speakers out there with enclosures etc. Ralph -----Original Message----- From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Cabin speaker specs --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:56 AM 7/15/2004 -0500, you wrote: >--> AeroElectric-List message posted by: "Ralph E. Capen" > > >Folks, > >After checking the archives for amplifying (pun intended) information - I >have decided that a small cabin speaker would be helpful for ground >operation (pre-flight etc). > >My audio panel instructions call for a 4 ohm speaker which seem to be >difficult to locate. 8 ohm speakers are available in abundance..... > >Will I fry something if I use a 8 ohm speaker? Or will it not work >properly - volume, freq, distortion...? > >Thanks, >Ralph Capen The 4-ohm callout on your audio panel is the recommended load for maximum output. If you use an 8-ohm speaker, the maximum output will be 1/2 that of the 4-ohm speaker. This says NOTHING about speaker efficiency . . . there are good 8-ohm devices that would put out more sound pressure than a cheap 4-ohm device. Don't worry about it. An 8-ohm speaker will work just fine for ground ops. If push comes to shove, install two 8-ohm devices side by side and you'll double the sound pressure by taking advantage of the amplifier's rated capabilities . . . but I'm certain that this will not be necessary. Bob . . . --- ________________________________ Message 15 ____________________________________ Time: 11:03:36 AM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Re: Cabin speaker specs --> AeroElectric-List message posted by: "Paul Messinger" Point of clarification, No load is often not an option! Some audio amps REQUIRE a load or they will fail. Instructions like "If no speaker than you MUST have a resistor of XX ohms across the leads". I have not seen a case where there was a problem between 4 and 8 ohms however, and remember the resistance as measured by an ohmmeter for a "4" Ohm speaker is not 4 ohms. You cannot determine the speaker impedance with an ohmmeter. Paul ----- Original Message ----- From: "James Foerster" Subject: AeroElectric-List: Re: Cabin speaker specs > --> AeroElectric-List message posted by: "James Foerster" > > Ralph asked: > "After checking the archives for amplifying (pun intended) information - I have > decided that a small cabin speaker would be helpful for ground operation (pre-flight > etc). > > My audio panel instructions call for a 4 ohm speaker which seem to be difficult > to locate. 8 ohm speakers are available in abundance..... > > Will I fry something if I use a 8 ohm speaker? Or will it not work properly - > volume, freq, distortion...?" > > Power input to the speaker is V squared divided by R, so you will get 1/2 the power into your 8 ohm speaker compared to the 4 ohm. This is 3 db, hardly noticable. As the load on the amplifier is less, you will hurt nothing. The opposite choice: 4 ohm speaker on an amp rated for 8 ohms, might lead to distortion. You are going in the safe direction by using a speaker with an impedance greater than the "rated" impedance of the amp. > > Jim Foerster J400, 80%,... > > ________________________________ Message 16 ____________________________________ Time: 11:15:30 AM PST US From: "Ralph E. Capen" Subject: Re: AeroElectric-List: Re: Cabin speaker specs --> AeroElectric-List message posted by: "Ralph E. Capen" Thanks...my audio panel has a switch and will function without a speaker. The impedance info is helpful too - I was gonna take an ohmmeter to it........guess I gotta read the label. -----Original Message----- From: Paul Messinger Subject: Re: AeroElectric-List: Re: Cabin speaker specs --> AeroElectric-List message posted by: "Paul Messinger" Point of clarification, No load is often not an option! Some audio amps REQUIRE a load or they will fail. Instructions like "If no speaker than you MUST have a resistor of XX ohms across the leads". I have not seen a case where there was a problem between 4 and 8 ohms however, and remember the resistance as measured by an ohmmeter for a "4" Ohm speaker is not 4 ohms. You cannot determine the speaker impedance with an ohmmeter. Paul ----- Original Message ----- From: "James Foerster" Subject: AeroElectric-List: Re: Cabin speaker specs > --> AeroElectric-List message posted by: "James Foerster" > > Ralph asked: > "After checking the archives for amplifying (pun intended) information - I have > decided that a small cabin speaker would be helpful for ground operation (pre-flight > etc). > > My audio panel instructions call for a 4 ohm speaker which seem to be difficult > to locate. 8 ohm speakers are available in abundance..... > > Will I fry something if I use a 8 ohm speaker? Or will it not work properly - > volume, freq, distortion...?" > > Power input to the speaker is V squared divided by R, so you will get 1/2 the power into your 8 ohm speaker compared to the 4 ohm. This is 3 db, hardly noticable. As the load on the amplifier is less, you will hurt nothing. The opposite choice: 4 ohm speaker on an amp rated for 8 ohms, might lead to distortion. You are going in the safe direction by using a speaker with an impedance greater than the "rated" impedance of the amp. > > Jim Foerster J400, 80%,... > > ________________________________ Message 17 ____________________________________ Time: 12:05:23 PM PST US Subject: Re: AeroElectric-List: Re: Cabin speaker specs From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Hi Paul, That's an interesting note about audio amplifiers requiring a load or otherwise being damaged. Do you know of an example of such a device? I had gotten the impression that most modern amps were pretty impervious to that kind of thing, but your note makes me think I should be more careful. Matt- N34RD > --> AeroElectric-List message posted by: "Paul Messinger" > > > Point of clarification, No load is often not an option! > > Some audio amps REQUIRE a load or they will fail. Instructions like "If > no speaker than you MUST have a resistor of XX ohms across the leads". > > I have not seen a case where there was a problem between 4 and 8 ohms > however, and remember the resistance as measured by an ohmmeter for a > "4" Ohm speaker is not 4 ohms. You cannot determine the speaker > impedance with an ohmmeter. > > Paul > ________________________________ Message 18 ____________________________________ Time: 12:16:16 PM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: Re: Avionics Master Switch --> AeroElectric-List message posted by: Brian Lloyd Rick Girard wrote: > --> AeroElectric-List message posted by: Rick Girard > > All, Anecdotal evidence only of damage done during shut down. The > shutdown checklist used in all the aircraft of the flying club to which > I belong has master off before leaning out the mixture and turning the > mags off and then back on to clear the cylinders. The maintenance > officer says we have had several radios fried by current spikes from the > mags when the master was left on. I can't speak to the claim, I just > follow the check list. Oh man, is this guy confused. There is no relationship between the mags and the rest of the electrical system unless someone has attached the P-lead ground to ground in the electrical system. (Actually, Cessna does this in the C-172 which makes no sense to me.) The grounds for the P-leads should terminate at the mags themselves. OTOH, turning off the battery master while the engine is running is not such a hot idea as you are creating the possibility of a spike on the buss now that the battery is no longer connected to absorb said spike. The master switch should stay on until the engine stops running. This is doubly important if you are using an internally-regulated self-exciting alternator. But the short answer, as Ron Koyich put it so succinctly, is, "BS." -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.270.912.0788 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. ________________________________ Message 19 ____________________________________ Time: 01:35:58 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Re: Avionics Master Switch --> AeroElectric-List message posted by: "Paul Messinger" ----- Original Message ----- From: "Brian Lloyd" OTOH, turning off the battery master while the engine is running is not such a hot idea as you are creating the possibility of a spike on the buss now that the battery is no longer connected to absorb said spike. The master switch should stay on until the engine stops running. This is doubly important if you are using an internally-regulated self-exciting alternator. You get a load dump from any alternator int or external reg and so goes the so called spike. I cannot think of any difference between int and ext reg except for contactor/relay dropout times. If your setup removes regulator power (for an ext reg alternator) say 200ms before removing the battery then you are safe. Both off at the same time does not stop the load dump from getting to the bus. BTW the contactor open time goes from around 5 ms to 50 ms when the diode coil supressor is added to a commonly used contactor. Contactor contact bounce on closing can and has damaged avionics and thus I was convinced at the time an avionics master was more than a convience. Load dumps on power off can also cause damage. This in the 1960's and 70's built avionics. Poor transient protection and blown cmos parts. Not sure if todays avionics could be damaged but the worst case load dump is impressive in energy 50v @15amps peak decaying over more than 150 ms is not trivial and this is above the bus V and current The contactor contact bounce I have observed in my current testing is NOT addressed properly in DO-160. In fact this very long multiple bounce was a major problem in the test series The kilovac brand contactor has essentially no contact bounce. My conclusion is that while modern avionics are less sensitive, load dumps can happen that exceed the requirements of DO-160 and thus the power on and off timing delays of the various relays and switches have the potential of causing nasty transients. Power on and power off sequencing is a major issue in many electronic designs. Thus while many or nearly all aircraft electrical systems may be safe the occasional acft will have problems. Paul ________________________________ Message 20 ____________________________________ Time: 01:35:58 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Re: Cabin speaker specs --> AeroElectric-List message posted by: "Paul Messinger" My comments are from several com radios I have installed. > > I agree that modern design should not need a load but if the avionics mfgr > says so then I do it. > > Look at the install manual and see if there is a note. Not all have such a > requirement. > > Paul ----- Original Message ----- From: "Matt Prather" Subject: Re: AeroElectric-List: Re: Cabin speaker specs > --> AeroElectric-List message posted by: "Matt Prather" > > Hi Paul, > > That's an interesting note about audio amplifiers requiring a load > or otherwise being damaged. Do you know of an example of such > a device? I had gotten the impression that most modern amps > were pretty impervious to that kind of thing, but your note makes > me think I should be more careful. > > Matt- > N34RD > ________________________________ Message 21 ____________________________________ Time: 01:50:55 PM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: Re: Cabin speaker specs --> AeroElectric-List message posted by: Brian Lloyd Matt Prather wrote: > --> AeroElectric-List message posted by: "Matt Prather" > > Hi Paul, > > That's an interesting note about audio amplifiers requiring a load > or otherwise being damaged. Do you know of an example of such > a device? I had gotten the impression that most modern amps > were pretty impervious to that kind of thing, but your note makes > me think I should be more careful. The problem occurs with transformer-coupled amplifiers. You won't find those in production audio panels these days unless you have one of those new-fangled hi-fi tube-type audio panels. :-) It can be an issue with some comm radios as they use the audio amp to modulate the transmitter through a transformer and couple the speaker to the audio amp through the same transformer. -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.270.912.0788 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. ________________________________ Message 22 ____________________________________ Time: 02:04:36 PM PST US From: Fiveonepw@aol.com Subject: Re: AeroElectric-List: Cabin speaker specs --> AeroElectric-List message posted by: Fiveonepw@aol.com In a message dated 7/15/04 10:58:08 AM Central Daylight Time, recapen@earthlink.net writes: > My audio panel instructions call for a 4 ohm speaker which seem to be > difficult to locate. 8 ohm speakers are available in abundance..... >>>>>>>>> Got my 4 ohm spkr at the aviation department at WallyWorld- (WalMart Auto) It's about 5" in diameter, cost maybe $7 and works great on my Microair 760.... From The PossumWorks Mark ________________________________ Message 23 ____________________________________ Time: 02:19:58 PM PST US Subject: Re: AeroElectric-List: Re: Cabin speaker specs From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Thanks - that sounds like something I have read somewhere.... Regards, Matt- > --> AeroElectric-List message posted by: Brian Lloyd > > Matt Prather wrote: >> --> AeroElectric-List message posted by: "Matt Prather" >> >> >> Hi Paul, >> >> That's an interesting note about audio amplifiers requiring a load or >> otherwise being damaged. Do you know of an example of such >> a device? I had gotten the impression that most modern amps >> were pretty impervious to that kind of thing, but your note makes me >> think I should be more careful. > > The problem occurs with transformer-coupled amplifiers. You won't find > those in production audio panels these days unless you have one of those > new-fangled hi-fi tube-type audio panels. :-) > > It can be an issue with some comm radios as they use the audio amp to > modulate the transmitter through a transformer and couple the speaker to > the audio amp through the same transformer. > > -- > Brian Lloyd 6501 Red Hook Plaza > brianl@lloyd.com Suite 201 > http://www.lloyd.com St. Thomas, VI 00802 > +1.340.998.9447 (voice) +1.270.912.0788 (fax) > > There is a time to laud one's country and a time to protest. > A good citizen is prepared to do either as the need arises. > > ________________________________ Message 24 ____________________________________ Time: 02:44:29 PM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: Re: Avionics Master Switch --> AeroElectric-List message posted by: Brian Lloyd Paul Messinger wrote: > --> AeroElectric-List message posted by: "Paul Messinger" > > > ----- Original Message ----- > From: "Brian Lloyd" > OTOH, turning off the battery master while the engine is running is not > such a hot idea as you are creating the possibility of a spike on the buss > now that the battery is no longer connected to absorb said spike. The > master switch should stay on until the engine stops running. This is doubly > important if you are using an internally-regulated self-exciting alternator. > > > You get a load dump from any alternator int or external reg and so goes the > so called spike. I cannot think of any difference between int and ext reg > except for contactor/relay dropout times. And the usual wiring practice is to have a DPST switch remove excitation from the battery master contactor and the field at the same time. If the engine is still running you have created the unprotected load-dump scenario. > If your setup removes regulator power (for an ext reg alternator) say 200ms > before removing the battery then you are safe. Both off at the same time > does not stop the load dump from getting to the bus. Right. Internally regulated and self-exciting alternators will continue to provide output until they quit turning. Turning off the battery master in that case is asking for a problem since the alternator will continue to generate power unless you have installed a contactor to disconnect the alternator from the bus. > BTW the contactor open time goes from around 5 ms to 50 ms when the diode > coil supressor is added to a commonly used contactor. Ha, I bet you are right. I never thought about that. > Power on and power off sequencing is a major issue in many electronic > designs. Thus while many or nearly all aircraft electrical systems may be > safe the occasional acft will have problems. I have always adopted the "better safe than sorry" approach and turned off the master after the engine stopped turning. -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.270.912.0788 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. ________________________________ Message 25 ____________________________________ Time: 03:29:36 PM PST US From: "Europa Forum" Subject: AeroElectric-List: Turn Coordinator --> AeroElectric-List message posted by: I have a new, never used, 3 1/8", American made (Electric Gyro Corp.), electric, Aircraft Spruce P/N 1394T100. List price in the AS catalog $489.00 USD. Will sell for $389.00 USD obo. Will ship anyway you wish at your cost. Tom Friedland Atascadero, CA. 805 460 9690 ________________________________ Message 26 ____________________________________ Time: 04:27:28 PM PST US Subject: Re: AeroElectric-List: Re: Avionics Master Switch From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Alternator output at shutdown is typically lower than any other time... After having flown the airplane for a time, the alternator has had a chance to recharge the battery (potentially the biggest continuous load in a system). If you turn off the lights and sirens before killing the alternator, the load dump is going to be smaller than immediately after startup (for instance). I know, I haven't quantified anything here. As well, you wouldn't typically be turning very many RPM when you shut down - this limits output. On externally regulated alternators, it would seem safe to turn off the alternator, then the battery? Question: Will your car's rebuilt alternator be damaged if you should turn on the headlights, wipers, A/C, heaterfan, rev up the engine, and then turn off the key? Seems like the load dump scenario. The alternator will continue to spin (producing output) for several hundred milliseconds after the key is pulled.... Regards, Matt- > --> AeroElectric-List message posted by: Brian Lloyd > > Paul Messinger wrote: >> --> AeroElectric-List message posted by: "Paul Messinger" >> >> >> >> ----- Original Message ----- >> From: "Brian Lloyd" >> OTOH, turning off the battery master while the engine is running is >> not >> such a hot idea as you are creating the possibility of a spike on the >> buss now that the battery is no longer connected to absorb said spike. >> The master switch should stay on until the engine stops running. >> This is doubly important if you are using an internally-regulated >> self-exciting alternator. >> >> >> You get a load dump from any alternator int or external reg and so >> goes the >> so called spike. I cannot think of any difference between int and ext >> reg except for contactor/relay dropout times. > > And the usual wiring practice is to have a DPST switch remove excitation > from the battery master contactor and the field at the same time. If > the engine is still running you have created the unprotected load-dump > scenario. > >> If your setup removes regulator power (for an ext reg alternator) say >> 200ms before removing the battery then you are safe. Both off at the >> same time does not stop the load dump from getting to the bus. > > Right. Internally regulated and self-exciting alternators will continue > to provide output until they quit turning. Turning off the battery > master in that case is asking for a problem since the alternator will > continue to generate power unless you have installed a contactor to > disconnect the alternator from the bus. > >> BTW the contactor open time goes from around 5 ms to 50 ms when the >> diode coil supressor is added to a commonly used contactor. > > Ha, I bet you are right. I never thought about that. > >> Power on and power off sequencing is a major issue in many electronic >> designs. Thus while many or nearly all aircraft electrical systems may >> be safe the occasional acft will have problems. > > I have always adopted the "better safe than sorry" approach and turned > off the master after the engine stopped turning. > > -- > Brian Lloyd 6501 Red Hook Plaza > brianl@lloyd.com Suite 201 > http://www.lloyd.com St. Thomas, VI 00802 > +1.340.998.9447 (voice) +1.270.912.0788 (fax) > > There is a time to laud one's country and a time to protest. > A good citizen is prepared to do either as the need arises. > > ________________________________ Message 27 ____________________________________ Time: 06:16:11 PM PST US From: "Rex & Jan Shaw" Subject: AeroElectric-List: The maintenance officer says we have had several radios fried by --> AeroElectric-List message posted by: "Rex & Jan Shaw" The maintenance officer says we have had several radios fried by current spikes from the mags when the master was left on.<< To which I say, "BS." I have just sold my Electronics repair business and retired after 30 years. My experience was not centered on aviation, never the less I strongly agree. In the early days of electronics getting large values in filter capacitors was not feasable and so spikes from start up surges would present themself to any radio circuit operating. However early valve based gear was unlikely to be influenced by this except perhaps one capacitor in the vibrator power supply and then only if it was a poor choice that was used. With the advent of solid state [ie:- transistors ] things were very much more susceptable to surges and spikes. Early solid state components were not up to handling any abuse and seemed to fail even for no reason. On top of that the filter capacitors were still not up to anywhere near the standards or capacities of today, so radio gear and the likes thereof were very susceptable at that period in time. This is where the idea of not allowing power to this gear during start up and shut down comes from. It was a very real necessity at that time. Despite the short comings in this regard of solid state at this time it presented much lighter radios etc that used much less power so they were used especially in aircraft where these features were very important. I would guess the adverse side of things re reliability was played down by the manufacturers. After all don't they still all do that today with everything. However now the situation has improved dramatically with solid state components and filter capacitors. There is also readilly available simple technology built in to any good aircraft radio etc to protect in this regard. Hence I agree that the precaution of turning off the master or radio should not any longer be necessarry. However you can see where the idea came from. It's just time the idea was let die a natural death so we can concentrate on relevant things and have our facts straight. Also it is desirable that where feasable we understand reasons why. Hence my reason for presenting this explanation. Strangely probably a lot of the younger generation that might be very good technicians probably would not realise all this as they just live in todays world. However it is yesterdays world that is eroniously affecting our thinking today. As I say my expertise is not in Aviation electronics so if someone can validly show me why I am wrong when it comes to aviation then I am all ears, but don't just tell me a lot of grandma's tales. Facts based on electronics please. Rex Shaw Australia Kitfox 19-4004 rexjan@bigpond.com ________________________________ Message 28 ____________________________________ Time: 06:47:54 PM PST US From: KITFOXZ@aol.com Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux --> AeroElectric-List message posted by: KITFOXZ@aol.com In a message dated 7/15/2004 8:20:26 AM Eastern Standard Time, BobsV35B@aol.com writes: Good Morning John, Thanks for the great description. Do you have any specific recommendations as to types or brands of flux or solder? Happy Skies, Old Bob AKA Bob Siegfried Ancient Aviator Stearman N3977A Brookeridge Airpark LL22 Downers Grove, IL 60516 630 985-8502 Hello Bob, I have always used Kester 63/37 solder and liquid flux. I don't know if others are any better or worse. Radio Shack would be just as good and convenient to most users. John P. Marzluf Columbus, Ohio Kitfox Outback (out back in the garage) ________________________________ Message 29 ____________________________________ Time: 06:54:51 PM PST US From: KITFOXZ@aol.com Subject: Re: AeroElectric-List: Solder - Rosin-core or paste flux --> AeroElectric-List message posted by: KITFOXZ@aol.com In a message dated 7/15/2004 11:27:37 AM Eastern Standard Time, echristley@nc.rr.com writes: Excellent practice for a perfect solder joint, but just one more step will make the job much easier. Thin the flux about 10 to 1 with alcohol. It only takes a minute layer of flux to block out the oxygen that ruins your day, and extra flux just burns and give you more to clean off. As a technician in an AT&T manufacturing plant, I used to put down a 150-pin, surface mount IC in about 30sec without a single bridge. The problem with cored flux is that it doesn't coat the parts until AFTER it is heated...which means that it has already had a chance to oxidize. Keep the thinned flux in a miniature, needle-tipped squeeze bottle and your work will improve ten-fold. Yes, this is a very good point that I forgot to mention. The liquid flux is constantly thickening in everyday use. One needs to add some alcohol from time to time to keep it in a viscosity range that is workable for the component size at hand. John P. Marzluf Columbus, Ohio Kitfox Outback (out back in the garage) ________________________________ Message 30 ____________________________________ Time: 07:36:12 PM PST US From: Ernest Christley aeroelectric-list@matronics.com Subject: AeroElectric-List: LED experiment --> AeroElectric-List message posted by: Ernest Christley This is the LED tail lamp that I have talked about a few times. It is a piece of plexiglass, drilled with several holes at appropriate angles, and then the holes are plugged with SuperBright LEDs. The first picture captures how the LEDs point off in different directions. It is brighter than my truck's taillights, and you can tell from the cigarette lighter plug how small it is. -- http://www.ernest.isa-geek.org/ "Ignorance is mankinds normal state, alleviated by information and experience." Veeduber ________________________________ Message 31 ____________________________________ Time: 10:15:15 PM PST US From: "David Carter" Subject: Re: AeroElectric-List: LED experiment --> AeroElectric-List message posted by: "David Carter" Ernest, the "list" stripped off the attachment. Could you post the picture to your website (I went there and didn't see a link to the tail light). David ----- Original Message ----- From: "Ernest Christley" Subject: AeroElectric-List: LED experiment > --> AeroElectric-List message posted by: Ernest Christley > > This is the LED tail lamp that I have talked about a few times. It is a > piece of plexiglass, drilled with several holes at appropriate angles, > and then the holes are plugged with SuperBright LEDs. The first picture > captures how the LEDs point off in different directions. It is brighter > than my truck's taillights, and you can tell from the cigarette lighter > plug how small it is. > > > -- > http://www.ernest.isa-geek.org/ > "Ignorance is mankinds normal state, > alleviated by information and experience." > Veeduber > >