HP 6200b

[kolonelkadat]

I recently got a 6200b that has some issues. Chief among them is the burned out diode cr34. According to the schematic, it is a RCA 1n3253 rectifier, silver, 500mA, 200PRV.

The datasheet for the 1n3253 gives specs I₀=.75 amps V_f=1.2v and I_r=5uAmps@PIR

I cant seem to find an exact match at mouser and I'm not sure which spec is most important for this particular diode.  My gut says that as long as PRV>=200 and I0>=750mA then it should be okay, but gut's a damn moron. If anyone could have a look at the schematic and let me know, Id appreciate it.

Also if you have any insight as to what may have caused the problem in the first place, I'd love to hear it.

schematic is here: http://www.hparchive.com/Manuals/HP-6200B-Scheamtics.pdf

[Andy Watson]

CR34 is not critical. Its function is to protect the supply against reverse polarity from the terminals. I would substitute a 1N400x series diode.

[kolonelkadat]

sounds good man. Thanks for the help.

[Paul Moir]

My 6294A would go negative when the current control was turned down all the way.  I was planning on changing that diode to a schottky so it would only go to -.3v instead of -.5v.  I went in another direction in the end.  No big deal though.