N channel JFET identification

[kraut]

Hi all,

I'm working on tracing a pedal and it's mostly SMD. I'm having trouble to idenfity a transistor. I've gotten one example off the PCB and mounted it on an adaptor board to measure it. See measurement pic attached. I've also made a pic of the transistor on the adaptor. It's hardly readable. I think it says "GB S" or maybe "G13 S". I'm hoping someone here can shed some light, pretty please.

Thanks for looking!

[george giblet]

Hi all,

I'm working on tracing a pedal and it's mostly SMD. I'm having trouble to idenfity a transistor. I've gotten one example off the PCB and mounted it on an adaptor board to measure it. See measurement pic attached. I've also made a pic of the transistor on the adaptor. It's hardly readable. I think it says "GB S" or maybe "G13 S". I'm hoping someone here can shed some light, pretty please.

Thanks for looking!

It's highly likely to be 6B.

MMBF5484LT1 SOT-23, N-channel JFET,

That's a smd version of the common 2N5484.

Lookup the Motorola or ONSemi datasheet.
IDSS approx 3mA, VP approx 1.3V

Those parameters predict ID (Vgs=0.541) = 3mA (1 - 0.541/1.3)^2 = 1mA
which is close to the measured 0.8mA.

[kraut]

Thanks George! Much appreciated.

I have some through hole 5484s here and they measure in the same ballpark. I'll try them out if I manage to complete the schematic and build it on vero.