Help with A123 transistor.

[HellasTechn]

Good day to all !

I need information on a transistor marked A123 (TO-92). Is it PNP or NPN ? it's pin arrangement or even better if anyone knows an equivalent.

It was mounted on the control board of a refrigerator. i have no other info on that.

Thank you all !

P.S.
I found it on e-bay but no info is stated about it.
http://www.ebay.com/itm/A123-TRANSI...hash=item3d37e94b01:m:mzjVANzwBdbvm4jdei-cvOg

 

[Minder]

NTE126 it is common for the 2SA to be left off the number.
2SA123 PNP.
http://alltransistors.com/transistor.php?transistor=7090
M.

 

[HellasTechn]

Thank you for the information !

I only have one doubt about the 2SA. becase of it's package. Like in the attached picture the one i have is TO-92.

The 2sa123 and nte126 are TO-18

 

[Minder]

In that application I would not expect it to be that critical, most likely any close PNP would suffice.
M.

 

[HellasTechn]

You are right. My problem is that i am not sure if this damaged A123 is the same as the 2sa123. What troubles me is that i dont know its pin arrangement and even if it is a PNP indeed or not.

It's probably the same but i just want to make sure...

 

[davenn]

You are right. My problem is that i am not sure if this damaged A123 is the same as the 2SA123.

Why ? .... 99% probability that it is

 

[HellasTechn]

that still does not solve my pin arrangement issue. Say i replace it with a close PNP like minder suggested, how can i be sure which pin is base, collector and emmiter since my part is TO-92 (not a TO-18)?

 

[Minder]

Legend toward you, pins down, left to right, e,b,c.
M.

 

[davenn]

that still does not solve my pin arrangement issue.

I only found one reference to the pin connections

that's why you need to invest in one of these ..... essential in the repairers workshop
I couldn't live without my one

http://www.peakelec.co.uk/acatalog/jz_dca55.html

 

[Minder]

I have a post into a supplier for original pin out clarification.
M.

 

[davenn]

Legend toward you, pins down, left to right, e,b,c.
M.

have you a reference for that ?

I have a reference with e other variations but not that one

 

[Minder]

A voltage measurement of the original transistor connection should confirm it, preferably with the old one removed.
M.

 

[HellasTechn]

Legend toward you, pins down, left to right, e,b,c.
M.

There is no legend on the pcb indicating e,b,c positions, it only shows the shape of the component (flat side , round side).

***It just crossed my mind that i do have a few C123 transistors in my hand. Any chance that they could be complementary and have same e,b,c arrangement ?***

A voltage measurement of the original transistor connection should confirm it, preferably with the old one removed.
M.

I cant do that because i only have the PCB not the whole refrigerator.

have a reference with e other variations but not that one

Yes, but still not sure that can help.

I have a post into a supplier for original pin out clarification.
M.

That would be the best. For now it looks like i am stuck. i will order a new one from e-bay, since i see no other option, and i will measure it when i get it. Meanwhile if you find anything please drop a line !

Thank you both !!!

 

[Minder]

If you can identify the power planes + and -, then a resistance check to each from the 3 pins should point to it, with a PNP the emitter will be towards the +ve rail.
and collector to the -ve.
The base somewhere in between.
Nothing back yet.
M.

 

[HellasTechn]

ok when faceing the flat (printed) side of the a123, its right-hand pin is connected to an sn74hc14n pin 14 which is VCC pin. so that i guess is the emitter ? then middle = base and left = collector ?

 

[HellasTechn]

CORRECTION the pin connected to VCC is the left hand pin...

its middle pin goes to pin 7 (GROUND PIN) of the same ic through a potentiometers middle (wiper) pin.

the right hand pin goes to the IC's pin 12 (marked 6y on the datasheet) pin 12 must be an inverted output

 

[Minder]

What data sheet?, for the I.C.?
Anything else connected to the IC Pin12?
If the IC was open collector output, the Tr collector could also be connected in parallel.
Left appears to be emitter.
M.

 

[HellasTechn]

I will try to make a schematic of the board for you to see and maybe figure it out !
It may take a couple of days before i post it because it is our Orthodox easter the comeing sunday...
The datasheet is this :
http://pdf1.alldatasheet.com/datasheet-pdf/view/27890/TI/SN74HC14N.html

 

[HellasTechn]

I only found one reference to the pin connections

that's why you need to invest in one of these ..... essential in the repairers workshop
I couldn't live without my one

http://www.peakelec.co.uk/acatalog/jz_dca55.html

I have a similar one (e-bay). What i dont have is an actiual A123 transistor to measure