ICOM 706MK2G PLL problem?

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Tom Rowinski:
I have an Icom 706MK2G which has been slowly dying over the last few years. Seems like every 6-9 months, it develops a new problem!

Fisrt, the PS/2 style DATA port PTT line went bad, causing the radio to sink 480 mA on the PTT line instead of the 3 mA it's supposed to. Then it developed the intermittant white noise problem on 2 meter FM RX/TX which I have seen others mention on this site.

The latest problem appears to be a PLL unlock issue. When tuning through the HF bands, the receive will go dead in certain spots- as if the antenna was disconnected. The problem is intermittant. As best as I can tell, when it happens, all RX dies below 1 MHZ, and I also lose receive between XX.000-XX.100, as well as XX.500-XX.600. This occurs all the way through 30 Mhz. So as I tune thru the HF band, the 100 Khz dead spots appear between .000 to .100, and again between .500 and .600 on the frequency display.

As suddenly as the problem appears, it clears up and the radio works fine. Sometimes, if I leave the radio tuned to an SW broadcaster in the affected segments, I can hear the radio making random popping sounds as if the PLL is unstable and on the verge of unlocking. If I am transmitting on an amateur band within the affected segments (when the problem shows up) the radio will rapidly drop in and out of TX mode, causing the TX/RX relay to buzz at around a 20-30 Hz rate.

Has anyone else had this issue? Just wondering what to look for. I think the problem may be heat related, as it is more apt to occur if I TX into a dummy load in CW mode on and off for a few minutes.

73, de Tom, KA1MDA


I had a similar problem on 2 meters and 70cm and sent my radio in for repair on August 4, 2008.  I just found out that the part for this will not be sent by Icom until late November or early December, so I am having the 706 sent back to me and I am going to sell it as-is.  It would have cost $330 to repair it and I understand they were going to replace the PLL circuit board.  I wonder since they are out of parts; this problem may be wide-spread.  


Christopher M. Hill:
I ran into a problem with Yaesu not supporting relatively recent radios with spare parts(FT 1000MP MK-V).  They then no longer participated in my ham radio spending.  I switched to Tentec.  It looks like Icom is going to go on my list.

Victor Camperi:
I have the exact same issue. Icom said NPF and had it for 2 weeks and then charged me for the NPF, I received the radio back and it worked for 3 days and now is back to its old tricks. I can not afford another radio at this time, so I think this hobby may be on its way out for me. Who else can repair this, can I do it myself?

Grant Laughlin - now W5XJ:
Try www.hamrepair.com his name is Cal and he just did a realign on my 706.



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