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I am trying to Identify this SMD component, Pin 1 GND , 2-VCC, 3-? Out I can identify top letter is C , Bottom is G11, I think it might be a transistor but it odd being connected to the main power rail. Part is from bremshey bike monitor. Unfortunately other identification is blocked out because it's burned out. enter image description here

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    \$\begingroup\$ It's labeled 'U4', so it's an IC not a transistor. My guess would be a linear voltage regulator of some sort. You can see that transistors are labeled with a Q, as there's a big Q5 over to the left. \$\endgroup\$ – brhans Mar 30 '18 at 0:58
  • \$\begingroup\$ good point, to the left is a 3.3V LDO what type of IC would have the label Cxx G11? \$\endgroup\$ – Ben Newson Mar 30 '18 at 1:10
  • \$\begingroup\$ ON the PCB it says CHANG YOW SM6665-K01 I tried to find the schematic but it's hard to find, \$\endgroup\$ – Ben Newson Mar 30 '18 at 1:12
  • \$\begingroup\$ It looks like old Rotamola silkscreen before Laser marking was used. Looks like centre pin is 0V \$\endgroup\$ – Tony Stewart EE75 Mar 30 '18 at 1:14
  • \$\begingroup\$ So why the marking of G11? if it's not a transistor? \$\endgroup\$ – Ben Newson Mar 30 '18 at 1:15

I figured it out, It turned out to be an LDO 5.0V the way I solved it was I replaced it with a 3.3. LDO and it worked but the display was very dim. I figured the next one up would be a 5V regulator, so I desoldered one from another PCB put it on and it works like a charm. Thanks for your comments.


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I agree. no idea,

but if one of the junctions isn't shorted determine if it PNP or NPN with a DMM then choose a 1W transistor that makes sense for V*I

You can always use a bigger part not SMD with higher Vceo.

e.g. linked to switch Motor in regenerator mode 80V? then 100mA, low V switch? then 30V 500mA

e.g. NPN 2SD1463 , PNP 2SB1045 (100V 50mA)

At least it is not an LDO like U7.
What event triggered the failure?

  • \$\begingroup\$ yes I saw this but I don't think DTB113ZKA is a SOT89 package, According to the PCB Pin 1 is GND and Pin 2 is VCC, Pin 3= Vout I guess, If it's a Digital Transistor why would it be connected to the main VCC? \$\endgroup\$ – Ben Newson Mar 29 '18 at 23:49
  • \$\begingroup\$ Does the C mean "Collector?" \$\endgroup\$ – Ben Newson Mar 30 '18 at 0:05
  • \$\begingroup\$ not normally marked... probably part of other markings burnt out \$\endgroup\$ – Tony Stewart EE75 Mar 30 '18 at 0:39
  • \$\begingroup\$ Unfortunately, I can't determine if it's PNP or NPN because each pin is an open. Any ideas to determine the original C B E pins? \$\endgroup\$ – Ben Newson Mar 30 '18 at 0:59
  • \$\begingroup\$ Is there a way to test this without replacing the part? Eg if pin 1 was GND and 2 was VCC then could I just put a jumper from pin 2 to 3, if it's acting like a switch? \$\endgroup\$ – Ben Newson Mar 30 '18 at 1:05

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