Help finding old HP transistors and IC's or substitutes? - Page 1
Forum section: electronics / projects

author: TERRA Operative
author_rank: Super Contributor
timestamp: October 19, 2018, 06:26:44 pm
content: I recently bougt a HP 4276A LCZ meter for myself and it has the option for Internal DC Bias that isn't fitted to my unit.The service manual has full schematics, BOM and PCB layout, so recreating the PCB will be trivial, however, sourcing obsolete silicon isn't....I have found most of the substitutes, but I am having a bit of trouble with a few parts, I'm hoping someone here might be able to give me a nudge in the right direction.Here's the parts I am looking for:- HP part number: 1854-0523Apparently this is a Motorola/Freescale part, with alternative part number SS3091It's a silicon NPN transistor, 1Watt, 150MHz in a TO-39 case (But case type doesn't matter to me)It might have a collector to emitter voltage rating of 40V and 500mA source cutoff voltage, but I'm not 100% sure about that.I can source these from ebay, but I'm looking at over $100 for a pack of 11 delivered.I need only one...I managed to track down some more reliable parameters:Pd= 1WFt= 150MHzVce= 160VIc= 0.5AIf I could only get a hfe value, I could work out a substitute....- AD7530LNAn 0.05% tolerance 10-Bit Multiplying D/A converter by Intersil.- LF13331N or LF13331D (LF13331N preferred)A JFET 4pole SPST-NO analogue switch by National Semi.If anyone can shed some light on sourcing or substituting these, please let me know!

author: tautech
author_rank: Super Contributor
timestamp: October 19, 2018, 06:43:36 pm
content: There's some good cross references at Sphere.They ask they not be linked but it's OK to link the page you can find them on.http://www.sphere.bc.ca/test/hpparts.html#crossGood luck with your hunt.

author: TERRA Operative
author_rank: Super Contributor
timestamp: October 20, 2018, 07:20:11 am
content: Ah yeah! I always forget about them...I found they have another part I need, a 1854-0358, although substitution parts are easy to get for that part and are cheaper anyway.I'll email them with my list and see what they say. Thanks!

author: tautech
author_rank: Super Contributor
timestamp: October 20, 2018, 07:26:46 am
content: Quote from: TERRA Operative on October 20, 2018, 07:20:11 amDid you spot the link to Master Consolidated 143 page HP Cross-Reference.

author: TERRA Operative
author_rank: Super Contributor
timestamp: October 20, 2018, 09:50:16 am
content: Yeah, I saw that one.I actually had more luck with using the Keysight online parts search first to find their substitutions for obsolete parts, then going back to those cross-reference documents on Sphere's site to find common part numbers.I found all the other transistors I need, except that damned 1854-0523/SS3091...I added some more reliable parameters I found to the OP. I would be forever indebted to anyone who could measure hfe and anything else they can manage for one of these that they might happen to have in their possession.....Also, after a bit of a poke around the Digikey website, I reckon I might be able to make the following substitutions for the other two parts:- 1826-0485/AD7530LN replaced with DAC10GSZ- 1826-0416/LF13331N replaced with DG442DYZ