Kenwood TH-28A owners?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KC0BIN, Jun 7, 2018.

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  1. KC0BIN

    KC0BIN Ham Member QRZ Page

    My normally reliable TH-28A has gone psychotic, I'm afraid......

    It was performing beautifully until it started to emit key-pad beeping noises at almost regular intervals; also, it will not TX or RX.

    I've reset the HT twice, both mem and CPU- didn't work. Checked the mem support batt, and it was 1.25v. I'm stumped!

    I did a search on the -28A and mysterious beeping, but no luck.

    Have any other TH-28A owners had, or heard about this problem?

    If the problem is terminal, it does give me a plausible excuse to buy a TH-78A, -79A or suchlike. I do revere the older Kenwood HT's. They set the standard for aesthetic "Cool" that no HT's have ever surpassed. :cool:
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    1.25V does not sound good for a lithium battery.

    How old is your battery pack ?
    KC0BIN likes this.
  3. KC0BIN

    KC0BIN Ham Member QRZ Page

    The batt is original, I'm sure. Not a bad service life for 27-odd years.....

    I'm no expert on lithium batts, I can tell you. I have no idea what the voltage drop would be to render it used up; age alone is enough.

    Do these mem-support type lithiums have a nominal 1.7V like other types? I think the one in my TH-28A is a Panasonic (?) circa 1992 (?)
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    Normally lithium is 3 volts or a little more.

    I have replaced the cells in many battery packs, It is just a little work to get the pack apart.

    Good Luck.
    KC0BIN likes this.
  5. KC0BIN

    KC0BIN Ham Member QRZ Page

    Many thanks!

    Just what is the technical name for those "memory support batteries"?? I'd like to do a bit of research in the Kenwood TH-28A service manual before I go poking around in there :confused:
  6. WA9SVD

    WA9SVD Ham Member QRZ Page

    I had to have my Standard C628A dual bander repaired for no transmit audio (RF was fine.) Fortunately, it just required a new microphone. But the repair gentleman replaced the battery as well saying it was prudent "preventative maintenance" after 26 years. Smart but honest man; he could have had another job in a year or two.
  7. WA9SVD

    WA9SVD Ham Member QRZ Page

    My Standard is the same vintage; ordered the day of the Northridge 'quake. I'd say get the battery replaced ASAP, before it leaks and ruins the radio. The voltage IS far below that of a healthy Lithium back-up cell!
    KC0BIN likes this.
  8. KC0BIN

    KC0BIN Ham Member QRZ Page

    Thanks, will do just that.
    Have to replace my collection of electronics gear & tools first; my original set burned up in my storage locker couple of weeks ago.......
  9. WA9SVD

    WA9SVD Ham Member QRZ Page

    "Battery packs" are usually a piece of cake. but I believe the OP is talking about the INTERNAL back-up battery, which requires disassembly of the H-T itself, not just an external battery pack.
    KC0BIN likes this.
  10. KA9JLM

    KA9JLM Ham Member QRZ Page

    For the age, They both need replaced.

    My guess is, The battery pack is the major problem.

    The internal battery just holds memory channel info.

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