After many years, one ham dug into the schematics and found that the real problem was some of the rigs weren't wired as shown in the schematic in the ALC area. If your linear can handle that, you're OK. For example, you might have your output adjusted to 50W to drive a linear, but hitting the key or mic results in a leading spike in excess of 100W. The other problem that most of the 781s have is a leading edge power spike. That just wasn't necessary and I don't advise it unless you're versed in adjusting magnets to get the CRT image right again. Like many people, I replaced the CRT just because there were some burned areas that really weren't visible in normal operation. I think that EVERY 781 would eventually experience this problem if it were shipped a few times. The vibration of shipping flexes the board to the point where traces can break. There's also a mechanical problem with the same regulator board - a heavy iron core transformer that was supported just above the board mainly by its thick leads. Unfortunately, the fan wasn't around early enough to prevent the damage to most of the 781s. The heat issue with the regulator is completely prevented by using the Sherwood fan. Other rigs with similar dynamic range numbers proved troublesome. I never ran into IMD problems while operating CW contests on 20 and 160 where the band was crowded with very strong signals. The fact that the close-in dynamic range number isn't above 80 dB was a non-issue for me. I'd say it's not a rig for someone who can't work on their own equipment. If you get past the common problems, it's a very reliable and well-thought-out rig.
While I primarily used it on CW for DXing and contesting, I also did a bit of SSB and RTTY with it. I used a 781 for a number of years before moving on to other things. Refurbishing the Icom IC-781 Regulator UnitĮffects of Line Voltage and Sherwood Cooling Fan on IC-781 Heating Traian YO9FZS' article "IC-781 & IC-R9000 technical and maintenance issues" (ZIP file) The LCD display module used in the Icom R-9000L will fit in the IC-781 īUT it costs over $1000, and is no match for the old CRT in image quality.Ī comparison between ICOM IC-7800 and IC-781 The CRT module, which used to cost $800, is no longer available,Īlthough replacement tubes (CRT) can be had on the surplus market. One should also consider that IC-781 parts are going to become scarcer as time goes by. With no technical skills/knowledge (appliance ops) OR those with limited financial means.Īt the present time (2010) one should not pay more than around $2500 for a used IC-781.
Personally, I would NOT recommend the IC-781 to radio amateurs Purchased by some amateurs with financial means that could afford it. Icom sold IC-781 into high-end amateur radio market for over $5,000 USD. Designed in Japan during early 1990s originally for government / military contract.
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