The Kenwood TM-V71 is a great dual band mobile set that is at home in the car or the home shack. It’s packed full of great features and has a good power output of 50W on both VHF and UHF. I’ve owned Icom, Yaesu and Kenwood dual banders and I just love the TM-V71 so it’s no surprise that I snapped up an ebay bargain for a faulty one (dated 2009) when I saw it.

This issue with this particular set is well know and is caused by some crystal filters that have been contaminated. Symptoms are low sensitivity on one or both sides of the radio and clicks, pops or crunches when receiving a signal. The fix is simple and just involves removing four crystal filters and replacing them.

Four crystal filters on the left hand side.

It’s an easy job and I was going to do it but, I didn’t have to. Kenwood issued a free repair notice when the fault was identified and Kenwood UK were still honoring the notice for a specific serial number range (serial numbers starting with 903 to 003). Off the radio went.

2 weeks later the TM-V71 came back, all repaired for the cost of the outgoing postage. Keen to see what Kenwood had done, I opened the radio up and put it on the bench side by side my late 2015 model. Interestingly, the 2015 model has a slightly revised PCB that has additional capacitors on the filter inputs where as the repaired 2009 model does not. I was half expecting Kenwood to change the entire PCB in the 2009 model but they only replaced the filters so I guess the caps are just an additional precaution and were deemed unnecessary?

DC Blocking capacitors on the newer TM-V71 filters.

Just as a precaution, I’ve ordered some spare ceramic filters and put them aside incase the problem returns. If it does, I will change the filters and modify the PCB to include some small DC blocking caps just like the newer PCB.



Share on Google+Share on FacebookTweet about this on TwitterPin on PinterestShare on StumbleUpon

«