Help! Peltor PTT - Troubleshooting (ZTactical Motorola Talkabout 1-Pin)

[Ming_the_Merciless]

Just got a pair of replica Comtacs, and unfortunately out of the box I'm having problems with the PTT, specifically the 1-pin for a Motorola Talkabout, the ZTactical version. The headset, Comtacs seem functional, noise cancellation, somewhat comparable to the real SwatTacs, (Black Comtacs), haven't tried interfacing the ZTactical mic and connector on the real one, but will try later if I can get the PTT functional to begin with. But I suspect it is a poor electrical connection on the PTT it self, but without a baseline, Element or otherwise, I can't make a comparison, not to mention I have absolutely no electrical background what so ever, or have a multi-meter. But here are what the guts look inside the PTT.

Should the two pins diagonal of each other, that hold the push-switch to the board, be soldered? And looks like the 4 wire leads that go onto the board need to be re-soldered too (weak solder at best). Anything else I'm missing here? I remember reading somewhere, or seeing someone place a capacitor on the board, but my google-fu, isn't strong tonight.

Any help would be greatly appreciated!

[mchlman]

It looks like the white wire is coming off, that one should be re-soldered and possibly the yellow. Don't go soldering the two blobs diagonal from each together. Your going to end up with one big short and you wont be able to fix it easily. That loose connection is my best guess. Get a multi meter and test for connection between the pin and the solder points on the four wires. Youll know for sure then if something is not good.

[Red62]

What are the symptons? does it sometimes work? Does it smell like burning? I agree, the white wire looks kinda frail, but it may not be the only problem. Can we get more deal in what it's doing?

[Ming_the_Merciless]

Originally Posted by mchlman

It looks like the white wire is coming off, that one should be re-soldered and possibly the yellow. Don't go soldering the two blobs diagonal from each together. Your going to end up with one big short and you wont be able to fix it easily. That loose connection is my best guess. Get a multi meter and test for connection between the pin and the solder points on the four wires. Youll know for sure then if something is not good.

To start with, I ruled out the possibility of bad radios by using a good functioning headset and thus I either have a fault PTT or Comtac. I hope it is just the PTT. I got the two points diagonal to each other soldered. Earlier the PTT just didn't function whatsoever, couldn't transmit or receive, but now after soldering I can at least transmit. Problem is, it's always broadcasting now, when I plug the pin from the headset into the PTT, with the noise cancellation on or off, it will be transmitting constantly. It seems the vertical position of the headset pin seated in the PTT will have an effect on whether I am transmitting continuously or if I can receive, a weak signal at best. Once or twice while I playing with the height pin I heard a signal, but more noise than signal.

After some more research, I found this Youtube video, which shows the guts of an Element PTT.

‪Element Peltor ptt for yaesu disassemble‬‏ - YouTube

Again to summarize, soldering the two points at least has got the PTT to transmit, just it's always on now, and I'm troubleshooting the headset-to-PTT pin height to find the sweet spot. I'll probably just bring it to some professional to trouble shoot it, some audio/visual guy, or a local radio/com specialist, but they're not open on weekends. I would return it, but turnaround time to Hong Kong and back, considering they are out of stock on this particular PTT, is too long of a wait.

Any other suggestions?



Just thought, unless soldering those two points are the reason my PTT is always transmitting, but then again, before soldering it didn't transmit at all. I don't know if I took a step forward or back now. Hmmm...

[Ming_the_Merciless]

Just a status update, good news, the PTT functionality works. The PTT worked intermittently before, ended up being a faulty switch, which has been replaced. To eliminate possible problems, the connections from the 2.5mm jack to 4 wire leads on the board were resoldered. Bad news, audio for both LH and RH sides are still not functioning properly, very low signal to noise ratio, more static and noise, there is some signal getting through as you can hear the diaphragm working, but mean either some faulty or improper connection or some internal resistance issue of the headset, impedance? At first the jack height played a difference, but as you can see from the pictures below, when the Comtac jack is inserted into the PTT, the corresponding metal leads seem to touch in between the insulated areas where they should be. Not sure what additional steps I can take to resolve the issue. Perhaps some in line amplifier of some sort to boost the signal? In meantime I've got a separate PTT coming in, hopefully that will work out of the box, and I don't get two lemons in a roll, assuming it's the PTT that's faulty and not the headset.

Front


Rear


Replica Comtac Military Plug (U174/U or Nexus TP-120) w/ Replica Peltor PTT


Ztactical Comtac Plug Mated w/ ZTactical PTT


Replica Peltor PTT Nexus TP-120 or U174/U Cover Closed


Replacement Switch (From LHS to RHS 1-Fault OEM Switch, 2 - Replacement Switch, 3 - Replacement Switch Filed and Fitted to Board, 4 - Replacement Switch Top Engagement/Click Assembly Filed and Fitted for Optimal Height For Peltor PTT)


Thinking About Getting A Female Nexus TP-120/TJ-120 For Connector



New PTT On The Way


Oh and just in case other people where also looking for a replacement switch, just in case their's takes a dive, the size of the OEM push/button switch is approximately ~0.372"X0.212"X0.415"(LXWXH), the length and width were measured roughly between the solder leads. I'll report back, if the status changes, if I can get this PTT up and going, or if the replacement one is functional.

[Ming_the_Merciless]

Good news, confirmed the headset is good to go, hooked a 3.5 to 2.5 mini-stereo plug into the PC, and I could use the Comtacs as headphones. So I assume the power output on the walkie-talkie, a older generation Motorola Talkabout just can't drive the Comtac, so I'm looking into building a in-line amplifier. Got the kit all built, tested the amp quickly with a 3.5mm plug from the PC, and the headset and the signal is significantly better, 20x gain - without the jumper, with jumper the 200x gain was overkill, on top of the dual gangpot I had enough head room to adjust it even more for other applications. Haven't wired it up to the PTT, and figure out how to bypass for the mic.





Ordered the LM386 kit from here:

I should have gotten just a single LM386 PCB board, as the dual one is over kill for the headset, and could probably contain the single one within the PTT unit it self with some mods.


http://www.electronics123.com/s.nl/it.A/id.349/.f


http://www.electronics123.com/s.nl/it.A/id.395/.f

Took the hardware, from a different single-pin 2.5 mm PTT, and going to use that as the input and outputs on the amplifier, need to find a good enclosure, and figure out the wiring from the output from the radio to the input on the amplifier, figure out what wires I need to bypass for the mic to pass through to the radios and also respectively the output from the amplifier to a 2.5 mm female input that feeds back to the PTT. Hopefully I can at least boost the SNR on the radio output, and still transmit on the PTT, and then close it all up. My IBH is set up ready to accept the Comtac, as soon as I get this all squared away.

[T@NK]

if its not working then just go buy a new one, these ptt repo are cheap anyway

[Amos]

Wow.. That's alot of work for a clone headset...

If you enjoy the tinkering, then all the power to you

[Ming_the_Merciless]

Finished! Well, sort of, got to tidy up the wiring on the headset mounted on the IBH and find some more ferrite cores to help reduce EMI and RF interference. But everything is good to go, finally figured out how to bypass the mic, so that the amplifier only would boost the input or radio output. Along the way I learned a number of things that might help someone else in the future. Motorola Talkabout uses some proprietary 2.5mm jack, slightly longer, at a total length of 13 mm. To shim for this length, three M3 washers will do the trick on a female connector. The output is mono, with the 3 connector TRS, Tip - Speaker, Ring - Mic +, Sleeve - Ground(Speaker)/Mic -. To bypass the amplifier, route the connector that goes to the ring or Mic +, and go directly to the output 2.5mm female on the amplifier. The Comtac plug, replica Nexus TP-120, a 4 connector TRRS, is the following: Tip - PTT Switch, Ring - Mic +, Ring - Ground (Speaker)/Mic +, Sleeve - Speaker. If you plan on using an LM386 IC, the jumper or gain of 200 is overkill, go with the gain of 20.



Guts of the in-line amplifier, found an enclosure that worked nearly perfectly for the PCB, but had to remove the dual gang pot to the top, and hand fit the lid so it would close on the box. Default the amplifier is driven by a 9V battery, but I added a small tamiya plug so it can be ran by some spare 8.4v mini batteries I've got laying around that never get used any more.





Also after doing some more research, apparently people with Midland radios had an issue with their PTTs, which was resolved with the following mods, note this is separate from what I did - as my signal required amplification.

Originally Posted by T@NK

if its not working then just go buy a new one, these ptt repo are cheap anyway

Yeah, that's what I did, two separate ones had the same issue. The low power GRMS/FRS radio I've got, single-pin Motorola Talkabout just can't drive the Comtacs alone. However, out from the three PTTs, I'd have to say the one built the best would be the replica Nexus U94, which doesn't require a PCB board, and seems more ergonomic. After tinkering around with all the replicas, I think I can build up my own U94 PTT.



The U94 is the one on the left side. Here are the guts of a real U94 for reference and also a Peltor PTT.

Originally Posted by Amos

Wow.. That's alot of work for a clone headset...

If you enjoy the tinkering, then all the power to you

No kidding, took some time too, because I really didn't have a chance to look at it, until the weekends where I'm free, the up side is I've become pretty proficient with soldering now. And have a better insight into comms, and how they work.

[ninsurgent]

Your remedy is overkill .

I have the same problem with the PTT. There's a conductive rubber inside the momentary switch. What I did is rubbed it with conductive poxy and it was done deal.

[ManateeMatt]

I know its bumping an older thead, but I was wondering, did you ever find a source for female nexus plugs? I like to tinkerer around as well, and as far as i can tell the only really big problem with the Element U94 is the shit ass female plug quality. (A button is a button, and a plastic case, although not super high quality, is a plastic case)

[solidgear34]

hey guys i have a problem with my motorola talk about. i just got a new round button style ptt for my old bowman headset but as soon as i plug everything in, no sound no nothing is coming out... please help!!!!

[deltaspear]

good morning sirs.has anybody tried modifying the realdeal u94 ptt to work with an authentic davies swimmer headset?