Just wired up a SSK for my Stryker and noticed it has noise when keyed. A hissing, rushing noise. I would appreciate ideas. Recap?? Here is a video of the problem.
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Turner Super Sidekick issue
- Thread starter Greg T
- Start date
A radio that's configured to use an electret mike is sending a DC voltage out the audio wire. If you can choose dynamic from the radio's setup menu, this might fix it. The SSK's cartridge is dynamic, but its output is amplified. The DC voltage feeding out of the radio upstream into the mike preamp's output circuit might be the culprit.
Maybe.
73
Maybe.
73
It's set for dynamic cuz I'm using a Plus Three on there now. I've used a mixer and headset, a D104, a Yaesu M1 reference mic and Turner plus threes all along. This particular mic makes the noise and if I talk into it it sounds kinda distorted and hissy. When I use the plus three I never fail to get Rave audio reports. People can't believe when I tell them what I'm running. But this one mic makes noise.
I'm just going to recap it. I can't think of anything else it might be, and three different AI searches and discussions all said the same thing.
Well, I quit. I capped it and cleaned everything up. Now I still get the white noise, and for some reason it will only key for about 10 seconds then unkey and won't key back up unless I wait a minute. Then it will key again. Soooo, back on the wall it goes for show and tell. Makes a good paper weight.
Yup, even shot cleaner in it and worked it. Getting loud background white noise when keyed. Now it only keys for about 10 seconds then quits.
Keying 10sec and quiting has nothing to do with board or components. 2 wires short through the switch contacts and key. So if the contacts are bad that would do it or something is wired wrong. The white noise could also be bad contacts. Or that little chip on the board if the caps didnt help.
Well, you know that and I know that. But it will key for about 10 seconds and then while the bar is still down, it unkeys. And it will refuse to key again until I let it sit for a minute. Then it keys. At first I thought the radio was screwed and the time-out was turned on or something, so I went back to my Pluss Three. All is well. Went to the SSK and again, keys for 10 seconds and then unkeys until it sits for a minute. Contacts are like new, in fact, the entire mic is like new. Just keys funny and sounds terrible.
Maybe a noisy/faulty transistor in the amp circuit causing the rushing sound or drifting resistor causing it to be biased incorrectly? I have one here, I will find the schematic and take a look. I'm curious if it employs a keying transistor.
Edit, no, no keying transistor, but that mfc4000b IC is a possible noise source. Can you monitor battery voltage/current while keyed?
Edit, no, no keying transistor, but that mfc4000b IC is a possible noise source. Can you monitor battery voltage/current while keyed?
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Well, maybe I can. But it's going to take two hands to run my meter and then somehow got a hold the key down quickly because it'll unkey itself in 10 seconds. I'll take it back apart again next week, didn't want to leave it laying in Parts on the bench because those parts always seem to have legs. I'll check on the voltage drop when it's keyed and see what's going on there.
I took a meter reading of battery voltage while keyed, and it holds steady at 8.93v. At idle it's at 9.03. It seems to be keying properly now that I retouched the solder joints. So I'm looking to replace the transistor and whatever other chip that is. After recapping the noise is still there, realizing I use cheap capacitors but there's been absolutely no change in the noise. So I'm thinking the Caps might be all right. Is there any place anybody knows of that I can buy onesies and two Z's of components now the Radio Shack is long gone? I'm looking to replace these two in the pictures.
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Good deal, I suspect that 1/4 watt audio amp IC is faulty and generating noise, but that goofy looking bugger might be hard to find. I bet that transistor is there to impedance match the element to the amplifier IC, it could generate noise and would be easier to find a sub so I would start there.
Edited to add, a quick giggle search turned up an eBay listing for a lot of 4, kinda pricey.
Mouser and digi have the transistor...