I am repairing a motor controller, Karon 241007LF rev 03, for a pool cleaning robot. The diode (D2) has failed, but I haven't been able to find the specs from the markings. The manufacturer logo looks to be a B, followed by U242 YK (see picture)picture of diode markings

  • \$\begingroup\$ If it doesnt follow PENS or JEDEC then its impossible to know what this diode is.Why dont you buy a new motor controller? \$\endgroup\$
    – Miss Mulan
    Jun 26, 2022 at 16:00
  • \$\begingroup\$ Hmm no polarity markings, a TVS perhaps? \$\endgroup\$
    – Bryan
    Jun 26, 2022 at 18:31
  • \$\begingroup\$ Unfortunately, the usual methods are failing me--I can't find any information on that 𝔹 logo, and none of the databases of SMD codes I'm aware of have anything for "U242". It's probably a TVS diode since its refdes is D2 (making it a diode) but it has no polarity mark (which standard and zener diodes would). However, speccing a replacement TVS diode shouldn't be too hard if you can determine what the normal maximum voltage of that rail is. Perhaps try turning it on with the diode removed (it's only for protection, TVS diodes are rarely required for functionality) and see what voltage it is. \$\endgroup\$
    – Hearth
    Jun 26, 2022 at 18:47
  • \$\begingroup\$ Thanks for the help!! The TVS suggestions seem to be correct based on where it is relative to the bridge and motor. The YK marking seems to track with the Little Fuse bidirectional marking for the SMAJ30CA with a reasonable clamping voltage for the given motor drive voltage and the package is correct!! \$\endgroup\$
    – Rosienej
    Jun 27, 2022 at 13:06
  • \$\begingroup\$ That B logo means it's from brightking (manufacturer). They are famous for TVS, Varistors, PTC, etc. We got an answer that confirms that! \$\endgroup\$
    – 15 Volts
    Jun 13, 2023 at 4:54

1 Answer 1


It is Brightking TVS Diode with part number SMAJ30CA

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