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UNknown SOT23 - need help identifying

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I have a fault on a car part and expensive repair. the fault is the following part.

I have spend a long time trying to find this part T1s
please see attached picture

Please can anyone tell me a part number?
Regards Jason
How did you diagnose the problem to this part?
I'd guess it's an NPN transistor similar to a MMBT2222A. But if overheating destroyed it you have to ask yourself what caused it to pass excess current? Unless you can identify the cause a replacement transistor will probably give up the ghost too.
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Thanks for your reply
I have just fitted BC17 (rs part number 807-5122) marking T1
This did not work.
In the past few weeks I have also tried
MMBT2369ALT1G Bipolar (BJT) Single Transistor, NPN (farnell part 1653624RL)
MMBT2369A Bipolar (BJT) Single Transistor, NPN (farnell part 9846719) marking 1S
BZX84B7v5 (rs part 800-9771) marking T15
BC807 -25LT3g (rs number 690 0079)

Thanks for your help do you have any other suggestions? I really need to get this part working. It was "dropped and hit tool box and cracked it"

Do some Voltage Tests on the Working Unit to try and determine if it is an NPN or PNP Transistor.
Possibly you also have Cracks on the PCB?
hi, no I have 2 working boards and also about TEN old boards I have found as spares repair ebay) i'm tring to get working. (im sure this is the fault)

Im trying to find this T1s part as im sure it will fix the other boards I have.

I have the 2 x sot's removed from the working boards, are in a safe place while I play with the working boards (swapping SOT's trying them on my car).

I will do measurements and take pictures - im even happy to pay a large reward if I can find the corect part!

Thanks Jason
On a GOOD UNIT, Measure the Voltages on the 3 Terminals of this part and Add these to the Above Picture.
This might help us to help you.
Measure the Three terminals, Relative to the Battery Negative
I've not found the exact part yes, but I have found the marking layout - the centre "s" means it's manufactured by Siemens or now Infineon and the 56 is a date code, June 2005. (Or '95 or '15)

Other data I've found says "T1" could be a a BCX17 or BSS63 - (which I can't find listed for infineon).
But, no normal transistor would give the diode voltage drop readings you are getting on that supposedly good part, they make no sense at all.

A cross reference I've found on a Russian site lists these as a possible T1 device and they make more sense with the readings:

Xref book:

Another possible is a diode array, but the readings don't match any type I have found - it's more like two back-to-back parallel diodes from centre to each end pin..

Edit - any chance the marking is "I1" with a bit of flux covering the bottom of the I ??
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"dropped and hit tool box and cracked it"
Is that fact, or someone else's report of what happened? I would have expected more evidence of impact, particularly affecting larger/heavier components.
Hi guys,
I have been busy finding R3130N44HA and its not that easy! I have found ONE data sheet that says a T1 marking with "s" being place of manufacture.

There are 4 types of R3130N part, all very slightly different. but all do almost the same function.
The only part I could get my hands on was R3130N22EA and this sadly did not work. I have tried to purchasing from china, eBay allibarber the 44HA type with no joy. Fitting this the automotive part did not work, refitting the 2 original T1s sot's the unit works.

Note Pin 1 is connected directly to 0V/Ground on the board

Any other help would be appreciated

Regards Jason

What do I know. Its a 5v board, pin 1 is to 0v/gnd & Pin3 is NOT CONNECTED
Pin 2 goes direct to pin 77 if an infineon IC C164CI

Port 5 is an 8-bit input-only port with Schmitt-Trigger charact.
The pins of Port 5 also serve as analog input channels for the
A/D converter, or they serve as timer inputs

Any ideas?

Regards jason
With only two connections, it's not an R3130N or a normal transistor.

It's most likely a diode / zener diode / voltage reference, or just possibly something like a Dallas "one wire" memory device.
You should be able to tell by what the component below connects to - the red pad on your board photo.

If that's a resistor going to some external connection, it's a protection diode of some sort.
If it's a resistor to 5V, it's likely a zener or voltage reference. Either way, that would probably make the pad nearer the CPU a capacitor

Some of the "T1" devices I found earlier were diodes, so it could be one of those.

Edit - looking back to your earlier tests on a good device, try two series pairs of back-to-back schottky diodes, such as BAT42.
(eg. wire two side by side opposite directions, then same again in series).
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