Piper Cherokee push to talk switch

jmarine225

jmarine225

Pre-takeoff checklist
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Jmarine225
In continuing my adventures as a new aircraft owner, the push to talk switch on the pilot side mounted on the control, is no longer functioning and does not transmit. I’ve attempted to replace the switch and it still does not transmit. Any possible suggestions on a repair before I dump another 1k into fixing this?
 
Good God man! You spent $1k on what exactly? In other words, specifically what has been done so far?
 
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The only thing a ptt switch does is connect one of the three leads from your mic jack to ground which triggers the transmit function. If you have a copilot ptt switch that works, chances are that the problem is either in the pilot mic jack or whatever wire(s) is(are) responsible for completing the run to ground when the switch is depressed. There are portable PTT switches with a built in mic plug, mic jack, and a PTT switch; you plug it into your mic jack, then your mic into IT'S jack. You could try that as a quick fix, but really it shouldn't be hard to troubleshoot. I can't remember which of tne three lugs on the mic gets grounded by the switch (tip, ring, or sleeve), but I'll be workong on my plane today and can check for you if you wish.
 
Timbeck2 said:
Good God man! You spent $1k on what exactly? In other words, specifically what has been done so far?
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Just updating some stuff. That’s about it. Had a flat tire, replaced the antique beacon with a new one, adsb. No major mechanical issues.
 
MuseChaser said:
The only thing a ptt switch does is connect one of the three leads from your mic jack to ground which triggers the transmit function. If you have a copilot ptt switch that works, chances are that the problem is either in the pilot mic jack or whatever wire(s) is(are) responsible for completing the run to ground when the switch is depressed. There are portable PTT switches with a built in mic plug, mic jack, and a PTT switch; you plug it into your mic jack, then your mic into IT'S jack. You could try that as a quick fix, but really it shouldn't be hard to troubleshoot. I can't remember which of tne three lugs on the mic gets grounded by the switch (tip, ring, or sleeve), but I'll be workong on my plane today and can check for you if you wish.
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Thanks. Much appreciated. So I opened the covered and the push to talk only had two wires running to it. I have a new switch and tried that with no effect. It doesn’t transmit. I would assume since it’s not transmitting it has to be a problem within those two words and wherever they lead to.
 
MuseChaser said:
The only thing a ptt switch does is connect one of the three leads from your mic jack to ground which triggers the transmit function. If you have a copilot ptt switch that works, chances are that the problem is either in the pilot mic jack or whatever wire(s) is(are) responsible for completing the run to ground when the switch is depressed. There are portable PTT switches with a built in mic plug, mic jack, and a PTT switch; you plug it into your mic jack, then your mic into IT'S jack. You could try that as a quick fix, but really it shouldn't be hard to troubleshoot. I can't remember which of tne three lugs on the mic gets grounded by the switch (tip, ring, or sleeve), but I'll be workong on my plane today and can check for you if you wish.
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In addition, the co pilot side push to talk transmits fine. No issues.
 
jason gula said:
Thanks. Much appreciated. So I opened the covered and the push to talk only had two wires running to it. I have a new switch and tried that with no effect. It doesn’t transmit. I would assume since it’s not transmitting it has to be a problem within those two words and wherever they lead to.
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Those two wires complete a circuit to ground. One of the two wires leads to ground, either directly or eventually (i.e., is connected to or spliced into another wire that leads to ground, for example the ground lug (sleeve) of the headphone jack) and the other wire is connected to tip lug (the longest one) on your pilot mic jack (or spliced into a wire that is). If you connect a wire to that correct terminal on your mic jack (the jack, not the plug on your headset) and touch it to any ground on your airplane, it should trigger the transmit function. If it does, and I'd bet it will, then you know that the trouble is somewhere in the wires leading to your PTT switch or the switch itself. If your PTT switch is integral to your yoke, the wire is probably run inside your yoke shaft and exists the shaft through a hole in the shaft underneath your panel. You'll see a length hanging and running over to your jack, most likely. Check those wires for continuity.
 
jason gula said:
In addition, the co pilot side push to talk transmits fine. No issues.
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Is the copilot switch also integrated to the yoke? What intercom are you using?

edit.. heading to the hangar to do some work until this evening. Will follow up later tonight. Let me know what you discover.
 
jason gula said:
Just updating some stuff. That’s about it. Had a flat tire, replaced the antique beacon with a new one, adsb. No major mechanical issues.
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Oh, okay. You made it sound like you'd spent a thousand bucks trying to fix a PTT switch. As Barry says, its a simple switch that just closes the ground loop when you push it. Stupid question/s: Are you sure you have the right type switch and that the correct two lugs of the three are soldered in correctly? How about the old switch? Can you put a multi-meter on continuity on the two lugs it was connected to while in the airplane, push the switch and get continuity? If the old switch still works, it probably isn't the switch. How about the ground connection? Is it tight? Could it be a broken wire? Those wires are pretty thin.
 
MuseChaser said:
Is the copilot switch also integrated to the yoke? What intercom are you using?

edit.. heading to the hangar to do some work until this evening. Will follow up later tonight. Let me know what you discover.
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I’ll hit both replies at once here. The wires do go through the controls and through the shaft behind the panel. I’m going to check on it later today to see if I can find the wire coming from the shaft over to the mic jack and go from there. Please let me know of you have any more info which would be helpful.
 
Depending on your equipment, the ptt wires might go to your intercom or audio panel first before keying your radio.
 
Doug Reid said:
Depending on your equipment, the ptt wires might go to your intercom or audio panel first before keying your radio.
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Okay thanks. If this helps at all, the intercom still works. Just the ptt does not transmit when pressed.
 
MuseChaser said:
Is the copilot switch also integrated to the yoke? What intercom are you using?

edit.. heading to the hangar to do some work until this evening. Will follow up later tonight. Let me know what you discover.
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I made it to the plane and it took all of 1 minute to figure this out. The wires coming out the back of the control shaft had a terrible splice job, possibly by a 5 year old. Regardless I'm just going to replace the entire wire. I'm guessing 22 gauge shielded but any different opinions out there?
 
Broken wire. CALLED IT!! :)

Glad you figured it out Jason.

Edit: Barry actually called it, I'm just taking credit. ;)
 
Timbeck2 said:
Broken wire. CALLED IT!! :)

Glad you figured it out Jason.

Edit: Barry actually called it, I'm just taking credit. ;)
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Hahaha.....all good and a simple fix. Just trying to figure the exact wire which is in there.
 
A much needed chuckle. Thanks to both, and glad it was an easy fix.
 
MuseChaser said:
A much needed chuckle. Thanks to both, and glad it was an easy fix.
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haha....well i'm not going to put the cart before the horse. It's not repaired yet, but i easily found the broken wires and an easy repair. An help or idea on the gauge/type wire to use for the PTT? I'm guessing 22 gauge?
 
MuseChaser said:
I can't remember which of tne three lugs on the mic gets grounded by the switch (tip, ring, or sleeve), but I'll be workong on my plane today and can check for you if you wish.
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Three sections on a mic plug. Tip, ring, and shell (proceeding from end to bottom, in that order). I was taught which was which by a dirty old man and cannot repeat his words here. Tip (end) is PTT. Ground the tip and the radio transmits. RIng (the center one) is microphone audio to the radio transmitter. Shell is the long part on the bottom and it goes to airframe ground.
Jim
 
jason gula said:
I'm on it. Thanks for the help.
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22 or 24. A couple of thoughts. If you have the room, use 2-conductor cable with a plastic outer layer and you will never have to replace it in your lifetime. Either way, be sure you use stranded wire. Solid wire was not meant to flex and will break after a few back-and-forths of the control column.
Jim
 
weirdjim said:
22 or 24. A couple of thoughts. If you have the room, use 2-conductor cable with a plastic outer layer and you will never have to replace it in your lifetime. Either way, be sure you use stranded wire. Solid wire was not meant to flex and will break after a few back-and-forths of the control column.
Jim
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Thanks for the help. I'm going to use the 22 gauge wire. Can I just purchase 22 gauge wire or is there "aircraft specific" 22 gauge wire which must be used with connectors also?
 
I'm not an avionics guru, so take this FWIW. I have found that solder tubes are one of the greatest inventions ever. If you're not familiar with them, they're basically a short piece of heat-shrink tubing with a ring of solder in the middle. Strip about 1/4" of each end of the wire, and insert in the ends of the tube so that the stripped wire is surrounded by the ring of solder. Heat up the tubing until the solder flows. You then have a solid connection and heat-shrink tubing to protect it and keep it from flexing. Here's one kit of many on Amazon: https://tinyurl.com/solder-tubes

YMMV.
 
Wow! I had not heard of those! Must have lived a sheltered life even being a "ham" radio operator for 59 years!!! SO I just followed your link and ordered a kit :)
 
Those solder tubes are especially useful when you want to tie in the shield of a two or three wire cable to ground. Strip the teflon sheath, clip off all but about 3/8" of the shield, pull the remaining shield back over the teflon jacket as you typically would when terminating coax, slip a solder tube on so thath solder band is around the shield, then insert a stripped short single wire pigtail from the back. Heat until the solder flows. Now, you've got a shrink-wrapped sealed strain relief for the separate wires leaving the bundle, and an easily identifiable and crimpable wire for tieing in the shield. Works great.
 
jason gula said:
Thanks for the help. I'm going to use the 22 gauge wire. Can I just purchase 22 gauge wire or is there "aircraft specific" 22 gauge wire which must be used with connectors also?
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At the risk of starting a flame war, you can't use hardware store wire, but you don't need "aviation specific" wire either. As I said, you can use 2-wire cable with a plastic outer sheath or plain #22, either of which is available at Fry's or any other electronic store. But if you use the plain wire, at least use some sleeving where the wire goes through or around a metal edge. Shrink sleeving is ideal for this. And stranded, stranded, stranded wire.

Tell you what, I've got several THOUSAND feed of #22 3-conductor cable (just cut one conductor off at each end). I'll send you (within reason) as many feet as you need for free. All you need to do is send me one of those Post Office "one price" boxes that will ship no matter the weight, self addressed, and paid for. It should hold something about the size of a 1 pound box of sugar. PM me for address.

JIm
 
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Well as much as I thought this was an easy fix, for the first time I put my small electronics welding skills to the test on "two" micro switches. Needless to say I will now be purchasing two more switches as those ones melted. Anyone have any tips for soldering these minature switches without melting the plastic in the damn things?
 
jason gula said:
Anyone have any tips for soldering these minature switches without melting the plastic in the damn things?
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Low melting point solder is a good place to start. Also, get a small, fine-point soldering iron (not one of those big soldering guns) on which you can adjust the heat. Set the soldering iron on a middle heat range. Be sure the contact is clean. Carefully heat the contact on the switch and flow a little solder on to it. Do the same with the bare wire. Then hold the contact and wire together, and carefully heat both so the solder flows, creating a solid joint. Since you have a couple of bad switches now, use them to practice.
 
@SoCal 182 Driver pretty much covered it well. The only thing I have to add is maybe try a little paste flux on the wire and switch terminals before tinning. It's not necessary if you're using rosin cored solder (and you should be),but it helps the solder flow faster.
Another point, and I can't stress this enough, is to make SURE the tip of your iron is in good condition and prepped properly. Let the iron heat up, drag it across a damp sponge or a brass scrubbie, touch solder to tip and let it lightly coat the tip. It should be bright, clean, and shiny. If not, repeat until it is. There's nothing worse than a tip with hot and cold spots.. that's when you start melting switches. The bit of solder on the tip helps with rapid and even heat transference. It's called "tinning."
 
jason gula said:
Anyone have any tips for soldering these minature switches without melting the plastic in the damn things?
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You'll need either a temp adjustable solder iron or one made for electronic soldering, not a $15 HF special as they are set too hot. Use only quality lead solder due to it's low melting point and not lead-free which usually doesn't melt till after the plastic melts. The rest is mentioned above.
 
Bell206 said:
You'll need either a temp adjustable solder iron or one made for electronic soldering, not a $15 HF special as they are set too hot. Use only quality lead solder due to it's low melting point and not lead-free which usually doesn't melt till after the plastic melts. The rest is mentioned above.
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That reminded me of a few other points. Your comment re heat settings is accurate, but a heat setting too low can cause problems too because of the time it takes to heat the junction to the point where the solder flows...if the iron isnt hot enough,heat has more time to travel further from the contact point and melt the switch. On my soldering station, I've found 340-370 degrees C to be a good range with a fine tip and delicate work. I sometimes go hotter if I want to work faster or a joint is particularly touchy, but there's less room for error. Also, and I forgot to mention this, use small gauge solder..the thin stuff..for fine work.
 
MuseChaser said:
but a heat setting too low can cause problems too
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True. But most solder job issues in this context and skill set tend to be caused by cheap equipment and lead free solder. Another suggestion would be for the OP to hit Youtube for a video on soldering which covers all the points being discussed here.
 
Is there room to use something as a heat sink to protect the switch from a less than experienced solderer?
Thin needle nose pliers and a rubber band come to mind.
 
lowtimer said:
Is there room to use something as a heat sink to protect the switch from a less than experienced solderer?
Thin needle nose pliers and a rubber band come to mind.
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It's a slippery slope. Too much heat sink and he'll have a cold joint. Not enough heat sink (with too much heat on the part), and he'll wreck the switch. My suggestion is to practice on something other than the switch to get a sense of how much heat/time it will take for the solder to flow.
 
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