It looks like that you were searching for something very close to the diode I need to replace: On my diode with red band was written: T2D37. It turned out to be a ST02D-170 from shindegen.Need to purchase this diode to repair my Panasonic Plasma TV PSU. T2D76 is written on its body and it has a red band on one side. Tried to Google/Digi-key...etc but to no avail. Can anyone help?
Although the name is different, this may help you to understand, what you're searching for:
cg120These transient suppressors all begin with ST03D-XXX where XXX is the breakdown voltage. The ones I know of are ST03D-82, ST03D-140, ST03D-170, ST03D-200
It's a zener and a regular diode face to to face (cathode to cathode), so when you try to read it in diode mode with a multimeter it will either read open (this is good) or shorted (this is bad), or read like a regular PN diode showing 650mV or so (this is also bad). It should always read open, and will never read like a typical 650mV PN junction diode and this may throw you off.
If it reads open, this is good. To find out which one you have, put it in a test circuit across a current limited voltage (maybe 5mA), and slowly raise the voltage up from 50V to over 200VDC and determine when it starts to conduct. That's the breakdown voltage you have. It will be close to those voltages I listed.
You might assume if the T3D 54 is 170V , then the T3D 37 might be 140 or 82 VDC. This could be right, or wrong. Where you got it from (i.e. how it was used in circuit) might also help you decide what its breakdown voltage should be.