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I have a dead controller with what's looks like a power transistor. I measured it as SOT-89 SMD package, it takes 36-42 V in and probably out 5 V. it's marked "BE RJ" sideway on it. I did find lot of BE Rn or BE Rc but Google can't help for that exact silkscreen. The collector is not connected to anything. And I guess it should be rated for something around 1 A. On a Chinese site there's one eventual match for a 2SB1260 in its T100R version but impossible to be really sure.

If anyone master alltransistor db enough to help, me I'll really appreciate it.

enter image description here

Edit so you see how my board is. enter image description here

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  • \$\begingroup\$ Are you sure the collector isn't connected using vias under the tab to provide thermal transfer as well as electrical connection? \$\endgroup\$
    – colintd
    Oct 12, 2023 at 15:36
  • \$\begingroup\$ no I'm not sure of anything yet. The picture is showing another revision of the board. the one I'm trying to fix blown up and burned all its connectors. I mean that transistor is clearly undersized as it's a recurring issue. The collector could be connected to the M7 diode below, for sure it's no to the ground. \$\endgroup\$ Oct 16, 2023 at 11:58

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This is probably a BCX55 60V, 1A NPN transistor, based on the label, SOT89 form factor, BE main designator and surrounding circuit.

Made by lots of people, with different lot codes, but BE is pretty consistent as the primary identifier.

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  • \$\begingroup\$ ok thanks I'll try and see if it works. \$\endgroup\$ Oct 16, 2023 at 8:10
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Could be a ROHM 2SB1260 PNP transistor.

enter image description here

enter image description here

(Source: lcsc.com)

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  • \$\begingroup\$ yeah that's the nearest match I got as well but wasn't sure if the RJ marking was for some swapped features like emitter -60v becoming +60v. thanks \$\endgroup\$ Oct 16, 2023 at 8:12
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    \$\begingroup\$ @bobylapointe If the datasheet doesn't say anything about the second marking, then it's usually not relevant for product identification. It's probably a lot code or s.th. similar. \$\endgroup\$
    – nanash1
    Oct 16, 2023 at 9:17

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