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Kenwood TH‑F6 and TH‑F7 Notes
By Mike Morris WA6ILQ
This radio has a design flaw: when you are using the external power supply jack the internal switch in the external power connector will disconnect the battery’s minus side from the transceiver’s ground. This way, the battery will remain in the charging circuit and the transceiver will be powered by the external charger/power supply.
The design of the external power / charger connector is weak, and easily broken. In addition, there is a chance of a momentary overcurrent that will open one of the two flyspeck-sized surface mount fuses inside the radio. F1 is in series with the battery, if F2 opens the radio will no longer work from external power or charge the battery, but the radio will still operate from a charged battery.
1) When charging/using the supplied wall-wart charger, or an external power supply, FIRST plug the charging cable into the transceiver, THEN put power onto the cable (this sequence is mentioned in the user manual, without saying WHY).
2) When charging is complete, first unplug the charger / power supply from the wall then wait a minute for the caps inside the charger to discharge, then unplug the charging cable from your transceiver. This prevents the current surges that blow the fuse.
3) An alternative to #2 is to add a series switch in the cord between the wall-wart charger and the radio plug.
If you blow the fuse, or damage the connector in the radio, you have a couple of options:
A) Send the transceiver to your local Kenwood service. Contact information is at the top of the main Kenwood page.
B) Contact someone who repairs commercial and amateur equipment.
1) Get an afternmarket drop in charger. Why Kenwood didn't offer one (or better yet, include it with the radio, is beyond me). The stock wall wart charger takes about 6 to 6.5 hours.
...OR... (or even both)...
2) Get an AA alkaline case and use rechargeable AA batteries in it (you can get AAs that recharge in 30 minutes). You can also have several sets of AAs and swap them in the field. Using the AA case also gives you the option of using non-rechargeable AA batteries - which can be handy on an all-day or all-weekend event, or in EMCOMM situations. Two AA cases are not an extreme option, when you are on a deployment you probably want to just swap battery packs, not a handful of AAs in one pack. And what will you do you do if you break a spring clip on your one pack?
The author can be contacted at: his-callsign // at // repeater-builder // dot // com.
Information provided from various sources as listed in the text.
Hand-coded HTML © Copyright date of last edit by Mike Morris WA6ILQ.
This page split from the main index page 16-Nov-2011.
This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.