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KY-97A as no sidetone

akschu

Well Known Member
Patron
So I have a King KY-97a with a sigtronics SPA-400 in an airplane I bought. Issue is that it doesn't have any sidetone, the headset is quiet while transmitting.

So I figure someone wired it wrong and start digging into the rats nest, and eventually separated the radio from the intercom and plugged it in directly. Still no side tone. I adjusted the pot on the top back and forth a few times and still no side tone. So I think the radio might have a problem, but don't want to fling money at it when I can just modify the SPA-400 to have side tone.

So my question is, is this a common problem? Is it reasonable to just work around it in the intercom? Is this something I should have looked at?

Thanks,
schu
 
RE: KY97 no sidetone

I recently helped a friend resolve a "no sidetone" problem with a KY97. Radio would xmt and rcv fine but no sidetone present in the headphones.

What we found after digging into the wiring, was the the original installer had used the KY97 speaker output pin E (Hi), pin 5 (Lo) for the input the audio panel.

After changing the wiring to use the 500 ohm audio output of the KY97 pin H (Hi) and 7 (Lo) sidetone problem was fixed.

If you haven't done it yet, it would not hurt to check your wiring to confirm the correct output pins of the KY97 are being used.
 
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My avionics shop just bench tested it and found it good, also adjusted the side tone up for me, so I think it's an install issue. I'll be building a new harness and installing a PM3000 to replace the SPA-400. I think I'll be much happier with that setup.

Thanks,
schu
 
I had this issue on a KY96. It took me a while to figure out that the sidetone trim pot works backwards" CCW increases volume.

Larry
 
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