Electronics > Beginners
Help identifying transistor
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ralun:

--- Quote from: amyk on September 19, 2019, 02:35:38 am ---

From the famous Russian site, the following match marking and package:

--- Code: ---B2xx 11AA020-I/TT 11AA020 SOT-23 2 Kbit, 1.8V UNI/O Serial EEPROM
B2xx R3111N122A R3111N SOT-23-3 1.2V Low Voltage Detector N-ch Open Drain Output
B2xx R3130N22EC R3130N SOT-23-3 2.2V Low Voltage Detector CMOS Output with Delay

--- End code ---
It is unlikely to be an EEPROM, the other two make more sense but you can look at the pinout of how it's used in the circuit to make a better determination.

--- End quote ---

Thanks, I'll look in to these.


--- Quote from: magic on September 19, 2019, 07:56:21 am ---

--- Quote from: ralun on September 18, 2019, 06:50:03 pm ---Anyone have a way of seeing if it's an PNP or NPN transistor?

--- End quote ---
The pinout of most SMD transistors is as follows:
left - base/gate
right - emitter/source
top - collector/drain

NPN conducts from base to emitter or collector, PNP conducts from emitter or collector to base.

I'm pretty sure it's an IC, though. On the good board, check which pin is connected to ground and what are the voltages on the other pins when it operates.

edit
LOL, an EEPROM in SOT23 and TO92 :wtf: I think I have seen everything now :D

--- End quote ---

Thanks, and I think you might be right on the IC part seeing the above sudgested ICs. They are all connected to ground, which I think makes sense looking at this datasheet page 15?
I can't measure any voltages though as the lights failure proctection is stoping it from running at all, it only displays an error light.

I went ahead and split the broken part, I don't know if it's possible to read anything from that but I attached two images of it?
ralun:
Ugh, tried to find a store that sells the R3111N122A-TR-FE.
Found two stores that stock it, one has a min. order of 893 units, the other one is waiting for a restock at the end of november.  |O

Took a walk and got an idea though, anyone think it would work to bypass it by wire like the attached picture?
Might need to skip the two blue wires though, don't know it would cause a short?

magic:
It seems a few candidate ICs have been identified and other unknown ICs may exist with similar codes.

Before changing anything, be absolutely sure that you know which IC it is and that its connections to other parts match the datasheet.
Just looking at ground doesn't say much, there is 33% random chance that any 3-pin IC has ground on the same pin as yours ;)
ralun:

--- Quote from: magic on September 20, 2019, 08:44:41 am ---It seems a few candidate ICs have been identified and other unknown ICs may exist with similar codes.

Before changing anything, be absolutely sure that you know which IC it is and that its connections to other parts match the datasheet.
Just looking at ground doesn't say much, there is 33% random chance that any 3-pin IC has ground on the same pin as yours ;)

--- End quote ---

Yeah that's true, got a bit excited that it might had been identified.
Guess to only real way of knowing is to measure voltages across it, but I need the broken pcb to send signal aswell for it to start.
Do you think my drawn jury rig above would work without shorting everything to hell?
ralun:

--- Quote from: ralun on September 20, 2019, 01:00:24 pm ---
--- Quote from: magic on September 20, 2019, 08:44:41 am ---It seems a few candidate ICs have been identified and other unknown ICs may exist with similar codes.

Before changing anything, be absolutely sure that you know which IC it is and that its connections to other parts match the datasheet.
Just looking at ground doesn't say much, there is 33% random chance that any 3-pin IC has ground on the same pin as yours ;)

--- End quote ---

Yeah that's true, got a bit excited that it might had been identified.
Guess to only real way of knowing is to measure voltages across it, but I need the broken pcb to send signal aswell for it to start.
Do you think my drawn jury rig above would work without shorting everything to hell?

--- End quote ---

Turns out I'm more of an idiot than I thought, ofcourse I can measure voltages, how else would it know not to turn on.
In my defence my craptastic multimeter takes 2-3 seconds to measure voltage sometimes though, so I was a bit hasty when I tried it before.

I just can't get my head around this though, I get:
0,75 V from left to upper leg. (3,14? V on broken pcb)
3,14 V from right to upper (most likely across the C2 capacitor? Same reading on the broken pcb)
2,4 V from right to left leg. (0,11 V on broken pcb)

But I don't get any measurements on the lane going to/from the left leg.
I once again made a picture and added the values I got while measuring.
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