[Icom] IC751A tech review and serial numbers

Mon, 11 Nov 2002 00:50:26 -0800

Hi Alex,

IC-751A's manufactured prior to 1989 (old Icom logo) had clearly-marked
concentric PBT and Notch knobs. The inner knob is PBT. The PBT shifts the
455 kHz filter passband relative to the 9 MHz filter passband. (S/N 1XXX ~
5XXX).

During 1989, some IC-751A's (new Icom logo) were released with
clearly-marked concentric IF SHIFT and Notch knobs. Again, the inner knob is
IF Shift and has an Off position. The IF Shift removes the 9 MHz filter from
the IF signal path (dreadful mistake!) and shifts the 455 kHz filter
passband relative to the carrier. PBT can be restored by unplugging a brown
wire jumper on the Main Unit board. (S/N 6XXX). The mod is here:

http://www.qsl.net/ab4oj/icom/icom.html#IC751A

At the end of 1989, once Icom settled the PBT patent-infringement suit, a
third series of IC-751A's (new logo) came out, with PBT restored. This
series continued until the radio was discontinued in 1993. Serial numbers
run from 7XXX to 10XXX.

All these variants are easily recognisable via the logo and the PBT or IF
SHIFT markings on the knob (bottom R/H side of front panel). The third
series is the preferred one.

Best 73,
Adam, VA7OJ/AB4OJ
North Vancouver, BC, Canada
http://www.qsl.net/ab4oj/
Icom FAQ Site:
http://www.qsl.net/icom/

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of TL
Sent: November 11, 2002 00:27
To: [email protected]
Subject: [Icom] IC751A tech review and serial numbers

Hello Gurus,
I might have an opportunity to buy an IC751A as a backup radio .
I know this was a "project radio" that turned out to be a good one some time
after the regular 751 was discontinued.

What  serial numbers/product years  are known to be O.K \ Notorious?
Do late models carry larger serials?

Strange enough, I couldn't find any technical-lab-review about the 751A.

Thanks in advance, Isaac, 4Z4TL

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