Christos’ Tecsun PL-390: problems switching between MW/LW

TecsunPL-390Christos’ trusty Tecsun PL-390 started having a problem recently. He writes:

“My PL-390 can no longer shift from MW [mediumwave] to LW [longwave]. I left it without batteries for some hours in order to achieve a sort of reset, but nothing happened. If I press the MW/LW button longer than usual, then it start presetting stations.”

I suspect this could simply be a problem with the contact underneath the LW/MW button. Has anyone else experienced this problem or found a way to fix it? Please comment!

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8 thoughts on “Christos’ Tecsun PL-390: problems switching between MW/LW

  1. HECTOR FRIAS JOFRE

    Since some time I can not write the frequencies directly on the keyboard. This affects me because I cannot directly type the frequencies of my preferred stations. All the keys failing any of them like the ETM must be pressed very hard for the Scanner to act.

    I do to save my investment

    Reply
  2. Paul

    Thanks Justin. My Tecsun PL-380 had same “problem”, but it seems only lack of manual from my side.
    Now I have LW back on my radio!

    Reply
  3. Crow

    Thanks Justin. The only problem I found was this lack of long wave, it sent me looking online for answers, and yours works. This is by far the best small radio I’ve found for many years, and it’s good to know that mine’s not mysteriously broken. The manual is actually excellent despite not making this easy to understand, and this radio is a serious tool, I’ve seen big expensive gear that failed where this works well. I only have one so far, but I’ll be buying backups. After decades of very poor designs, we finally have something that breaks new ground the way nothing has since the early 1980’s.

    Reply
  4. Christos

    I would like to thank all the friends who replied and Thomas as well, who published my query.
    Justin’s advice worked immediately so I had not to disassemble the unit which is quite clean as I use it indoors as a bedside radio.
    I suppose that the next time I will have to follow Alexander’s procedure because as far as I know, in our homes, steam from cooking, humid etc sit between the rubber mat and the PCB in various devices.
    Greetings from Athens,
    Christos

    Reply
  5. Heinz Hammerling

    Clearly, Alexander’s answer is the solution.

    An additional comments.
    I have had similar problems with the (almost identical) TECSUN PL-380 and the PL-606 (plus the Grundig M400 –made by Degen ?). Specifically, the PL-380 would not respond to pressing of the memory button. Result, the “Alarm” function could not be set to a new station. The Grundig M400 and Tecsun PL-606 could in the end not be switched “on” or “off” (Power Buttons failures).

    In my opinion Alexander’s solution is beyond what the average radio user/ owner is willing to do.

    Probably a good idea to let these Hongkong mfgs. know (by way of angry blogs) that a cent or two spent extra on the keyboard would help improve their poor quality image.

    Reply
  6. DL4NO

    The PL-390 should be no different than all those radios: The keyboard consists of inter-digit structures on a PCP and a sculptured rubber mat above it. The contacts are made by pressing a pill of some conducting material onto the PCB.

    The PCB traces may be corroded. Or some dirt might prevent a low enough contact resistance. This construction normally withstands quite some mechanical abuse.

    My way with such problems is the following – you might want to try it with a defective pocket calculator or so:

    * Carefully open the device. Especially look out for the key caps unless you wish to clean separately 🙂

    * Remove the rubber mat. Normally this can be done quite easily.

    * Use a pencil eraser to clean the contacts below the rubber mat.

    * Check the contact side of the rubber mat for any dirt.

    * Use the chance to clean the display, knobs and so on.

    * Put everything together again.

    Good luck!

    Greetings from Germany,
    Alexander

    Reply

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