Correction: [Icom] 756 ProII Odd 6M Behavior

Thu, 16 Jan 2003 20:28:20 -0500

Correction:
	Should have said that SWR is LESS than 1.2:1. Sorry for the confusion.

William J. Wickstrom, Chief Engineer,
Surge Performance Sound.
[email protected]

-----Original Message-----
From: Ed Parish K1EP [mailto:[email protected]]
Sent: Wednesday, January 15, 2003 6:41 AM
To: [email protected]
Subject: Re: [Icom] 756 ProII Odd 6M Behavior

At first it sounded like RF feedback into some input like the key or ACC
lines.  Then you said you had the problem into a 50 ohm dummy load, so RF
feedback might not be it.  But then you said the SWR was greater than 1.2:1.
Therefore, I would again look at RF feedback.  Disconnect any wires to the
pro except for power.  KEy the radio with the transmit button on the front
panel (in AM,FM, or RTTY).  See if the power control does anything.  If not,
send it back to Icom, the final amp or some other stage is oscillating.
Check it out with a spectrum analyzer or another Pro's analyzer.

At 04:38 AM 1/15/03 -0500, you wrote:
>Hi, Guys:
>            Here's the story. My 'ProII acts very strange when I transmit
on
>6 meters with the internal tuner disengaged. On any mode with a carrier
(cw,
>am and fm-haven't tried rtty or ssb) I am unable to reduce power below full
>output, regardless of power control setting. In addition to this, on CW
>output appears (as indicated on both internal and external power meters)
>only after key contacts are held closed for about half a second or so. All
>appears normal when I engage the internal tuner with the front panel
button.
>All is normal on all other bands and modes. I have confirmed this behavior
>into two different non-inductive 50-ohm dummy loads. Both the "Auto Tuner
>Start" and "PTT Tune" functions are disabled in the start menu. SWR is >
>1.2:1. I have not done a hard reset of the microprocessor, but I have
>powered the radio off via the front panel power switch and disconnected the
>power cable from the rear panel for around 20 seconds or so, just to see.
Of
>course, the radio is off warranty as of 12/17/02! Any ideas?
>
>William J. Wickstrom, W1IK
>USECA Morse Instruction Coordinator
>[email protected]; [email protected] <mailto:[email protected];%[email protected]>
>
>
>
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