959 squeal on tx

[smoke1982]

Has anyone had a problem with 10z rf squeal when case is on but perfect when case is off

 

[2315 Robert]

Has anyone had a problem with 10z rf squeal when case is on but perfect when case is off

Where do you hear this squeal? With case covers on there has to be something (cap, resistor, audio ic, pll, that is spewing) that is bouncing around with the cover on.

 

[Tallman]

Pinched wire maybe?

 

[nomadradio]

Loose ground screws around the edge of the main circuit board. Especially the ones at the rear corners.

73

 

[smoke1982]

No. I've checked and checked til ready to bust it lol. Radio works great until you put covers on. Somehow rf isn't all going out antenna. Was wondering if anyone else has had a similar problem.

 

[nomadradio]

All the transmitter RF feeding out to the antenna passes through those ground screws at the corners and rear edge of the circuit board, carrying it to the aluminum frame, and then to the body of the antenna socket.

The factory routinely ships these radios with the antenna socket loose, the ground screws loose and the side-mounted mike sockets loose.

A new radio brought in to be "turned up" would get all those fasteners tightened before we give the radio back to the customer.

If someone has done this to the radio already, that's good.

If not, this prevents the ground side of your RF power from reaching the antenna socket.

73

 

[smoke1982]

Thx for help sir. I've checked all that already though. I've been pulling my hair out. But again. Thanks

 

[kaos513]

Thx for help sir. I've checked all that already though. I've been pulling my hair out. But again. Thanks

Maybe is mic issue?

 

[Onelasttime]

Well how about you tell us exactly what you checked and how you checked it. Not saying it has to read like a write up for the FAA just a list of what you checked and how you checked? This way we do not act like a dog chasing it's own tail and we are on the same page! Thanks!

I have to say 99% of the time a squeal is a ground issues. Once you eliminate the obvious following the steps for an alignment is a good place to start.