The only way you'll know is if you replace the suspected components and operation returns to normal. However, look out for ' MISTAKEN CERTAINTEES '.
#Ic 706 serial numbers archive#
I own two of these radios and will archive this in case I run across a similar problem. Thanks for the info, article or not (like it really matters). While tapping with a wooden stick can help find the problem, it's still affects some parts around what you tap. While not a good fix, it would at least verified that the parts were surely the problem. Sometimes a resolder clears up the problem, at least for a while. Should I assume a 'resolder' has been tried on the parts? Some style of cap tends to 'swell' and with time go intermittent. I used the Murata parts on my redesign and the problems were cut by maybe 2 orders of magnitude. Where I work there were two used in an antenna design, and they were a nightmare. I've seen a lot of problem with SMD varicaps. I wouldn't say it was misleading, but I too would have waited until it was fixed before posting. And then post the results of your findings. If it were me, I would have waited until the new parts had arrived and were installed, to guarantee your synopsis was correct. Thanks for writing up your experiences with the 706. In point of fact, the more components, the likelier that a system failure may occur. 'One would not expect a variable capacitor to be at fault in a VCO. One would not expect a variable capacitor to be at fault in a VCO.
#Ic 706 serial numbers series#
After all the IC706 series is out of production since 2010 and in due time more and more problems will arise. While interesting for IC-706 users, why is this an article?įor the sole reason that this is a very rare fault and other people might need this information.
These trimmers are Murata SMD types that are very small 3x3mm and one would never suspect that these would make a short.Īnyway I am going to reorder some new SMD trimmers and replace them.ħ3, Stan/PA8C Member Comments:This article has expired. So the two 6-10pF SMD trimmers are at fault. When tapping on the trimmer capacitors for VCO1 and VCO2 I could reproduce the problem. I opened the tin can where the VCO is located and tapped with a trim key on several components. That was the case so the culprit has to be in the VCO. 216 MHz and tuned an Icom R10 receiver on the VCO frequency to establish if I could here it there too. So I figured out that the VCO mixes on approx. I checked the voltages from the 3 regulators on the PLL board bud couldn't find anything wrong there. It took me about 3 nights to identify the problem and first of all I suspected a bad soldering joint or something like that.Ĭhecking the PLL circuit diagram I noticed that the modulation circuit uses also part of the receiving circuit so I concentrated on that. After heating up (approximately 20 minutes) the transceiver produces a crackling noise and a lot of his heard from the internal speaker when on 2 meters FM/AM/SSB/CW.
Icom IC-706MKIIG PLL Problem Stan Joosen (PA8C) on February 6, 2014