[ICOM] IC-706 MKII, misc.

[Mort Arditti]

Kurt,

You may be pushing the 'poor' 706 MKII.

According the Icom specs, this radio's usable temperature range is 14 to 140 
Deg. F.
LCD displays are temperature sensitive.

When manufacturers specify operating temperature range, they will 'push' the 
limits.
Will the radio deliver full power out at 140 degrees ambient for a prolonger 
period of time?
If the air temperature is 140 degrees F, inside the radio it may be much 
higher and the
semiconductor junction even hotter. Even if the radio continues to work, the 
reliability will
suffer.

On the low temperature end the gain of some semiconductor devices may be 
(likely)
reduced at low temperatures.

73,

Mort, NA6MA


----- Original Message ----- 
From: "KD7JYK DM09" <kd7jyk at earthlink.net>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Thursday, September 03, 2009 7:19 PM
Subject: Re: [ICOM] IC-706 MKII, misc.


The lowest it has gotten here is -22ºF, the screen gets sluggish around the
mid-30's, 20's, teens, single digits, I wait a few seconds after pressing a
button to see what the radio indicates.  The hottest, +123ºF air temp.  The
screen starts getting dark around 120, darker as the temp gets higher.  I
have an FDA inspector thermometer stuck in the center vent on my dashboard,
it stops at 165ºF and is usually beyond that, 170-ish I would guess.  At one
time I had a digital thermometer that went higher, the temperature topped
out at 184ºF with the sensor in the middle of the cab, out of the sunlight.
150+ is common in the sun, though I don't recall ever looking at the
thermometer to determine at what point the screen goes black, I hop in the
truck, glance at the pegged temperature guage, turn on the radio and lean
over to see what frequency I am on, it's too dark to read in direct light
from a normal sitting position.

I have had my 706MKII for eleven years now, horrendous temperature cycles
every year, though slow, the head does get hot, the fan in the body cycles
regularly.  I've used it in the cold and heat and though I am sure it drifts
a little, on-air reports indicate nothing out of the ordinary.  A problem
has shown up recently, but it appears to be mechanical shock related.

The screen is polarized, and depending on which direction, and which
direction your sunglasses are made, the screen will appear normal or dark.
A friend recently commented on this, she discovered the cheap glasses she
was using had one lense 90º off compared to the other.  One eye clear, the
other black when looking at LCD screens.

Kurt

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