¿ªÔÆÌåÓý

  1. HP-Agilent-Keysight-Equipment
  2. Messages
Single Messages Topics Expanded

Re: HP 140B LVPS -12.6V Not Working

 

Hi David,

I saw some of your comments on another site (eevblog?) regarding 1854-0071.? It appears I have the 4-071 TI001 version.? If these are indeed failure prone, then possibly that's what happened in my case.

I didn't want to remove it unless I had good cause but since it tests in circuit the way it does, then I think there's good reason to at least remove it and test it out of circuit.? If it is indeed bad, then I can at least try a 2n3904.

If HP did switch to 2n3904s for that P/N, then I wonder if those are good for any/all instances?? If not, then I might want to get a supply of 2n3704s since, as you can see, that's not the only one on this board (and, maybe, on other boards in this scope).

Thanks again,
Barry - N4BUQ



1854-0071 is one of the very common small general purpose transistors used all over HP TE, 1853-0020 is the other common one.
It depends on which manual you look at, I've seen 1854-0071 (marked 4-071) listed as 2N3391 and as a selected 2N3704 in different manuals, they were made by various manufacturers and pinouts vary.
I've found original parts fitted marked MPS3391 in a HP 180, the 4-071 or 1854-0071 seems to be the most often failed part I find in HP scopes & other TE.
Later they used 1854-0215 which is a 2N3904.

A few of the common one and the generic part listed, from manuals.

1854-0071 = selected from 2N3704
1853-0020 = selected from 2N3702
Those are listed in the 432A pdf.

1854-0215 = 2N3904
1853-0036 = 2N3906
And those are listed in the 3310A/B pdf.

David

Join [email protected] to automatically receive all group messages.