SOT-23 identification

[OscarM]

I am trying to identify a SOT-23 used in an MRI coil of ~2006 vintage.
I have tried online part marking databases and books.
I have come up completely blank. No candidates at all.

From the circuit around it I know that this is used to translate from -5/0V logic levels and +5/0V logic levels.

Viable parts (in my mind) are N-JFET, some arrangement of prebiased BJTs or depletion mode N-MOSFET.
I don't think there is any reason for it to be a custom part and the volumes are so small that custom is unlikely.
There is no need for anything special with regard to permeability or magnetic field immunity and these things
are typically full of standard parts like 74HC' and normal FETs and transistors. (Clearly connectors and
capacitors are a different matter.)

I have two of these coils. One works and one doesn't. The pictures attached are of the parts on the two coils.
The manufacturer of the coil is one of those that supplies multiple big MRI OEMs so I don't think there is a
particular likelihood of it being from a certain Dutch vendor.

Any assistance appreciated.

[t1d]

This is way outside of my knowledge base, but... There is a YouTube guy who goes by the name of "xraytonyb." His channel is (mostly) about vintage stereo amplifier restoration. However, he owns a commercial x-ray machine repair company. Tony is a most excellent person (IMO) and is very gracious in sharing and teaching. He is likely a good source of information, for you.

Here is his channel information.
https://www.youtube.com/c/xraytonyb

Maybe you can dig around on his site and find out how to contact him with your question. However, keep in mind two things...
- If this piece of equipment can hurt you and you are not a professional electronics person, he may not be willing to help you. And, that is fair enough.
- Some professions do not share the tricks of their trade, because it effects their economic livelihood. And, that's fair enough, too.

Hope that helps.

[OscarM]

1) Thank you for trying
2) Thank you for your concern wrt safety. I take safety seriously.
3) I will try to get in touch with xraytonyb. I will report back here if I manage it or learn anything else that is relevant.
4) I have changed my mind about the type of device that is in question. It is a simple NPN. Also, it translates from -5/+12V to 0/+5V logic.
5) I will also try the folks on reddit.