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433 MHz RF Transceiver — Parallax Forums

433 MHz RF Transceiver

ValeTValeT Posts: 308
edited 2014-12-08 17:03 in Accessories
Hi everyone,

Ran into a little problem helping my brother with his science fair. One of our 433 MHz transceiver modules kind of sparked and had smoke coming out of it. I diagnosed the problem as the lowest orange capacitor on the board blowing up.

Anyone had this problem before or know what's going on? We were careful and followed the guide exactly.

Thanks for the help,
ValeT

Comments

  • LeonLeon Posts: 7,620
    edited 2014-11-26 08:08
    Impossible to say without more information.
  • PublisonPublison Posts: 12,366
    edited 2014-11-26 08:16
    ValeT wrote: »
    Hi everyone,

    Ran into a little problem helping my brother with his science fair. One of our 433 MHz transceiver modules kind of sparked and had smoke coming out of it. I diagnosed the problem as the lowest orange capacitor on the board blowing up.

    Anyone had this problem before or know what's going on? We were careful and followed the guide exactly.

    Thanks for the help,
    ValeT

    If it's the newer Tranceiver:

    http://www.parallax.com/product/27982

    It's hard to tell if the capacitors are ceramic or Tantalum. From past experience, Tantalums will burn or explode with reverse polarity.
  • ValeTValeT Posts: 308
    edited 2014-11-26 08:35
    Publison wrote: »
    If it's the newer Tranceiver:

    http://www.parallax.com/product/27982

    It's hard to tell if the capacitors are ceramic or Tantalum. From past experience, Tantalums will burn or explode with reverse polarity.

    Yep, we're using the newer ones.

    We checked and the circuitry looks fine. Maybe it was the code? We used the standard code minus a couple of debug statements and if statements.
  • PublisonPublison Posts: 12,366
    edited 2014-11-26 08:54
    ValeT wrote: »
    Yep, we're using the newer ones.

    We checked and the circuitry looks fine. Maybe it was the code? We used the standard code minus a couple of debug statements and if statements.

    Were you driving them with VIN or VDD? They don't like more than 5 volts max.

    Code can't smoke the cap.
  • ValeTValeT Posts: 308
    edited 2014-11-26 11:11
    Publison wrote: »
    Were you driving them with VIN or VDD? They don't like more than 5 volts max.

    Code can't smoke the cap.

    We are driving them with VIN.

    Thanks for the help Publison!
  • ValeTValeT Posts: 308
    edited 2014-11-29 04:25
    It might be worth noting that we are using a second one of the same model, both were bought at the same time from Parallax, that has an identical circuit as the first one but when tested didn't blow up.

    Could it have been a bad cap? Is there any way to replace the cap and not have to get a new module?
  • LeonLeon Posts: 7,620
    edited 2014-11-29 04:40
    It looks like a standard tantalum capacitor. Replacing it will be quite easy, especially if you use some Quik Chip to remove it.
  • ValeTValeT Posts: 308
    edited 2014-11-29 06:05
    Leon wrote: »
    It looks like a standard tantalum capacitor. Replacing it will be quite easy, especially if you use some Quik Chip to remove it.

    What size capacitor do I need?
  • LeonLeon Posts: 7,620
    edited 2014-11-29 08:56
    The same value and size as the existing one.
  • PublisonPublison Posts: 12,366
    edited 2014-11-29 09:21
    I suspect the value is unreadable due to the burning. Read the value from the adjacent ones. They may be the same or close.
  • LeonLeon Posts: 7,620
    edited 2014-11-29 10:16
    Or, read it off the working unit.
  • PublisonPublison Posts: 12,366
    edited 2014-11-29 11:38
    Good call Leon Forgot that he has a working unit.
  • $WMc%$WMc% Posts: 1,884
    edited 2014-12-08 17:03
    Make sure you don't use the VIN power any more...You need 5volts regulated. VDD
    '
    Don't let the magic smoke out!
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