Please help identify this transistor, and a possible substitution. It's from a built-in phono/USB preamp from an Austrian manufactured turntable. Thanks!

[J Pineda]

..

[Peter BENSCH]

Welcome, @J Pineda​, to the community!

Please try to clean the surface with the marking a bit, maybe then you can read better what is written on it.

Is what I can currently read there correct?

ST (e3)

LES3

4

GE 214

Regards

/Peter

[J Pineda]

Hi Peter,

Thanks for responding so quickly. The transistor was damaged prior to my obtaining the board it came off of, so its markings are a bit difficult to read. Under 10X magnification, I can more clearly read:

ST (e3)

EES3

A

GE 214

Best,

James

[Peter BENSCH]

Sorry, I have searched all my sources of knowledge but have found absolutely nothing. If you can't find anything else, you could try to draw the schematics around the component including the first stage before and after, plus find the required voltages, maybe I can help you draw a conclusion from that.

Regards

/Peter

[J Pineda]

Thanks Peter,

Thank you for your efforts. I'm working without a schematic, as the company which produced this does not provide any schematics to their service agents or customers. I'll try to work out the schematic. Is it possible that ST produced this transistor as an ST-branded version of the General Electric 214 (GE 214)?

Cheers,

James

[Peter BENSCH]

No, the GE stands for the origin of the chip and 214 for the date code in the format YWW. Only the last digit of the year has been used, so 2 could stand for 1992, 2002, etc. The marking was definitely in line 2 and 3, i.e. EES3 A.

Unfortunately, many such components have already been discontinued, so there is no more information about them.

Regards

/Peter

[J Pineda]

Great information! That means I can quit wasting time on the GE 214! It'd be better spent reverse engineering that section of the board.

Cheers,

James

[J Pineda]

Hi Peter,

The part # a gave you was incorrect. It is actually LE33 A (or 4). I was able to recover the part number by gently abraiding the surface with very fine sandpaper.

[Peter BENSCH]

Ok, then we found it after all: it is the LE33ABZ, a very low drop out regulator for 3.3V, where the A stands for 1% output tolerance (C stands for 2%). The regulator itself is still available, but unfortunately no longer as an A version in TO92.

Maybe you can find a LE33ABZ somewhere, otherwise you should be able to use the LE33CZ if 33mV more tolerance is acceptable.

If the problem is solved, please mark this thread as answered by selecting Select as best, as also explained here. This will help other users find that answer faster.

Good luck!

/Peter

[Piranha]

EDIT: few minutes too late...

I'm guessing, but it could be LE33. The third line is probably the letter A, which could mean a version with 1% accuracy.

https://www.st.com/en/power-management/lexx.html

P.S. @Peter BENSCH​ , the placement of LE33ABZ-AP in the datasheet Table 1 is clearly wrong as it's a 3,3V device, not 5V.

[Peter BENSCH]

@Piranha​ was a bit faster than me, but we came to the same result. :grinning_face:

Yes, you are right, the typo you mentioned is definitely one, and should be read a LE50ABZ-AP instead of LE33ABZ-AP. Thanks for this tip!

[J Pineda]

Thanks @Piranha​ & @Peter BENSCH​,

Funny. I was going through that data sheet and was momentarily confused by the same typo. But...I put the LE33 on a 9v led tester and voilá, 3.3v! Out of circuit, the le33 outputs 3.36vdc. In circuit, 0.01V.

Thank you both for helping me resolve this.

Cheers,

James