Kenwood TS-430s Display Memory Problem

Discussion in 'General Technical Questions and Answers' started by W3EGM, Oct 26, 2017.

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  1. W3EGM

    W3EGM Ham Member QRZ Page

    My TS-430s doesn't retain the displayed frequency after being powered off. I replaced the 3v battery with no success. Also checked the voltage on the memory IC power pin and at the battery voltage when the power is off and both read 3v. What else could be going on?
     
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    Does it lose it even if you leave the power supply on ?

    Did you do a reset after replacing the battery ?

    Good Luck.
     
  3. W3EGM

    W3EGM Ham Member QRZ Page

    Yes, even when the power supply is left on the display always returns to 14.000. I did find that the Memory Channels store and recall a frequency correctly but all revert to 14.000 after a power off and then on.

    I am not familiar with reset. Could you explain?

    Thanks
     
  4. KA5IPF

    KA5IPF Ham Member QRZ Page

    The battery is connected thru a diode to Pin 20 of IC6. With the power turned off there should be ~3v. When power is turned on it should be 4.5v. Make sure that is correct.
     
  5. W3EGM

    W3EGM Ham Member QRZ Page

    With power off Pin 22 (VCC) is 2.75v and with power on it is 4.26v. Measuring across the battery I get 3.1v.
     
  6. W3EGM

    W3EGM Ham Member QRZ Page

    Another clue... I can store and recall the frequency correctly in the Memory Channels but after power off/on all Channels go back to 14.000. It seems that may indicate that the circuit that switches power from powwr supply to the battery is not working. But as I indicated in a previous post, the voltage at the memory chip appears within range before and after power off.
     
  7. KA9JLM

    KA9JLM Ham Member QRZ Page

    It is a diode. The one that Clif mentioned.

    Did you check the voltage on pin 20 of IC6 ?
     
  8. W3EGM

    W3EGM Ham Member QRZ Page

    I did not check voltage at Pin 22. According to my schematic, the battery is connected through a diode to Pin 22 (VCC) not Pin 20 (Read/Write) of IC6. So I assumed Cliff was referring to the power pin (22). With power off Pin 22 (VCC) is 2.75v and with power on it is 4.26v. Measuring directly across the battery I get 3.1v.
     
  9. KA9JLM

    KA9JLM Ham Member QRZ Page

    OK. I could not confirm the pin number, My schematic is poor quality.

    Clif is the man and normally knows his pin numbers for the Kenwood radios.

    2 pins off was close. I am clueless. 3.1v for a fresh new battery seems low, But should work. I am sure you double checked polarity.

    Good Luck.
     
  10. KA9JLM

    KA9JLM Ham Member QRZ Page

    Dupe, Inet error.
     

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