Have the Kenwood TM-V71/V710 Filter Issues Been Resolved?

Discussion in 'Mobile Radio Systems' started by NR8Q, Jul 9, 2012.

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  1. M0GVZ

    M0GVZ Ham Member QRZ Page

    Thats fair enough Alan. I don't know enough about it to comment as to whether or not that was the problem. The only thing I can confirm is that Kenwood have revised the board certainly in the one I bought last year and the modification is basically an official version of the fix linked previously.
     
  2. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    I did send an e-mail to the one person I thought would know about this. He referred me to a gentleman in Phoenix, who is a consulting engineer. I did send him an e-mail, but haven't received a reply. However, in the meantime I did dig up some info on the problem, and it parallels what Jesse commented on—it was a series of bad filters, whatever the bottom line cause was.

    I cannot speak for the SV8 who posted the electromigration theory on his web site, and I don't know what his background is. And, I'm not a filter guru as I openly stated at the onset of this thread. That said, I know enough about electromigration that I find his theory very suspect. Electromigration is indeed a worry in large-scale, and titanic-scale integrated circuitry where the migration path is often measured in angstroms! A monolithic crystal on the other hand is measured in thousandths of an inch. Thus, common sense would tell me, that if electromigration was the actual cause of failure, then endo-environmental contamination has to be catalyst!
     
  3. KA5IPF

    KA5IPF Ham Member QRZ Page

    I have taken apart some of the "bad" filters and there is signs of liquid contamination on the plates. One person went so far as to clean the plates and reassemble the filter and it worked perfectly. I never tried. My theory is the filters were improperly sealed at the factory and when the PCB went thru board wash the filters were contaminated and subsequently failed.
     
  4. KAISERM715

    KAISERM715 QRZ Member

    Excellent info. I picked up a used TM-V71 over the weekend and found that it fell w/in the effected S/N range.
     
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