cold radio problem

[prkaye]

My ICOM A210 has been giving me a problem. The problem appears to exist during hte first few minutes of operation, until the radio warms up, an appears to be worse when the ambient temperature is lower (assuming because it takes the radio longer to warm up).
The problem is that the radio is constantly in the RX mode - the RX indicator is illuminated, and i hear a constant static. When I depress the PTT I can transmit as normal, and when an actual transmission is made from another aircraft, I can hear it without a problem. But between radio events, my unit is stuck on RX and i hear this annoying background static. As I mentioned, the problem seems to get much better when the radio warms up. This suggests to me a problem internal to the radio itself.
Any ideas?

[JDanno]

Years ago I had an ICOM HAM radio that would do something similar. The shop took some spray chemical that would come out very cold and kept checking out all the transistors and chips until they discovered the one that was bad. Replaced it and has been perfect since.

[schristo@mac.com]

Stuck PTT when cold?

[Loboflyer]

Sounds like the receiver squelch circuit. Does the setting for "SQL LEVEL" in the menus make a difference for you? If not, there may be a problem with the circuit.

It is typical for amplifiers to have increased gain at cold temperatures, and yours might just be breaking the squelch if you haven't set it before. If the SQL level doesn't make a difference it is possible you have bad components in the receive path and a trip back to Icom is indicated (unless others have ideas to check).

[prkaye]

Stuck PTT switch would put the radio on constant TX, not RX.

Squelch Level... I wasn't aware there was something user configureable in the radio for that. I'll check out the manual. i played around with the squelch on my intercom, but of course that had no effect on the radio itself.

[prkaye]

I just checked the manual. There are two menu items for squelch level.

AM SQUELCH LEVEL (Squelch mode for AM mode operation)
FM SQUELCH LEVEL (U.S.A. Version Only) (Squelc mode for FM mode operation)

I assume the normal mode of operation (that I would be using) is "am mode"?
I'll try that setting... I guess I would increase that setting to solve my problem?

[Loboflyer]

Originally Posted by prkaye

I just checked the manual. There are two menu items for squelch level.

AM SQUELCH LEVEL (Squelch mode for AM mode operation)
FM SQUELCH LEVEL (U.S.A. Version Only) (Squelc mode for FM mode operation)

I assume the normal mode of operation (that I would be using) is "am mode"?
I'll try that setting... I guess I would increase that setting to solve my problem?

Yup, AM level is what you want. Increase should be the desired effect (Icom users confirm this?). As with the knob settings on the older radios, you want to find the level where the noise just disappears and then maybe one setting higher to avoid annoying false trips.

[elippse]

The spray method is the one to find problems such as a bad solder joint or a defective component such as a resistor, capacitor or IC. Sometimes resistors that are soldered to a board contract so much that they develop a crack and change value, then as they warm up they start to work again. I had a problem where a wire jumper that passed through a circuit board would contract enough that the copper wire would shrink and separate circimferentially from its monel plating until it warmed up. Boy! was that a puzzler!

[Lycosaurus]

Phil,

Before you go changing those settings, are you getting the squelch breaking open on the apron close to the taxiway at CYSH? I have an Icom A-200 and have had the squelch open on me on occasion in that area. Move around some and the squelch closes.

Have not looked into it any further but there must be some interference in that particular area. Maybe you are seeing the same thing as I.

[prkaye]

Hey alfio... I have experienced that on the apron before, but today the squelch stayed open in flight most of the way to kingston. Hopefully increasing the setting fixes it.