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Some early Icom IC-775's have a problem in that the signal transmitted on the SUB frequency is also transmitted on the MAIN frequency in Split or Dual Watch operation.
I have found out that there are at least two versions of the PLL board on the market. This is what I have found out so far:
The B4304E board is the one I have; SM2LTA and I (SM4RNA) have checked it on a spectrum analyser with > 80 dB dynamic range, and found it to be OK.
There is an older B4304D board which has a modification performed by ICOM on the solder side of the PLL PCB just about where the B-PLL is located. I cannot verify whether it works OK or not. I have not made any measurements on this board. I have only seen it with my own eyes, so I know that it really exists.
There is also an even older version of the B4304D board which does not have the modification on the solder side. I can not confirm or deny that this PLL board has the bleed-through problem, but I know that this board is used in one of the first 775s that was sold in Sweden. My guess is that this board may have a problem.
Unfortunately it seems that one cannot be sure that the radio is OK just by checking the serial number. The radio I saw with the unmodified B4304D has a serial number above 1500. My radio with the later B4304E has a serial number around 1200, and was imported from Japan and sold to me just before the IC-775 was discontinued. I have some theories about why my later radio has a lower serial number, but will keep them to myself until I can get some more info about this issue.
73, Anders SM4RNA
A. Farson VA7OJ/AB4OJ edited Anders' original text, and created this page.
Last updated: 01/03/2006
