HP 54201D - transistors / ics? - Page 1
Forum section: electronics / repair

author: David Chamberlain
author_rank: Frequent Contributor
timestamp: August 15, 2020, 09:21:25 am
content: I have an HP 54201D scope with a bad channel. I've traced the problem to either a transistor or ic just prior to the ADC.Can someone help identify a couple of components?First is TO-92 markings"[Motorola logo] 6414-636BECC"Could this be a BC636 ?https://www.onsemi.com/pub/Collateral/BC636-D.pdfDoes not make sense looking at it for the base to be on pin 3??Second is a 6 pin TO-5 metal can. Directly before ADC."[Morotola logo]4-4578638"Last line is date code '86 fits manufacture date.I need to pull the board and reverse a schematic but if anyone knows these parts it would help me get started.Thanks

author: KevinA
author_rank: Regular Contributor
timestamp: August 15, 2020, 06:09:09 pm
content: Sphere BC in California have a list of HP semiconductor cross referenceshttps://www.sphere.bc.ca/download/hp_xref-free.pdf

author: precaud
author_rank: Frequent Contributor
timestamp: August 15, 2020, 08:54:23 pm
content: David, those are abbreviated HP part numbers. Look for 1854-0457 and 1854-0636.

author: David Chamberlain
author_rank: Frequent Contributor
timestamp: August 15, 2020, 10:17:47 pm
content: Quote from: KevinA on August 15, 2020, 06:09:09 pmThanks Kevin, that's going to be a valuable resource. I had found this one bulletinhttp://hparchive.com/Bench_Briefs/HP-Bench-Briefs-1987-10-12.pdf.. while trying to decode a opamp on the same board.Quote from: precaud on August 15, 2020, 08:54:23 pmPrecaud, I'm wondering how did you arrive at "1854" for the first four digits?If I just search Kevins document for "0636" I get.1826-0636 03285 AD7525KN - X Analog Devices 18pin DIP1853-0636 03334 2SA812 - X Philips SOT-23 PNP1855-0636 00039 NE71084-06 - NEC weird package FET.Search for "0457" I find.1853-0457 02037 2N5400 - TO-92 PNP1901-0457 02062 QSRD-4652 - ??1826-0457 03406 LM325H - Dual opamp, 10 pin metal can1820-0457 02910 N8162N - ??Here is a pic...

author: precaud
author_rank: Frequent Contributor
timestamp: August 16, 2020, 12:33:01 am
content: Quote from: David Chamberlain on August 15, 2020, 10:17:47 pmThe "4" is the last digit in the prefix. Experience led me to fill it in with 185 for transistors. The suffix is 4 digits, so add a leading zero.They typically only abbreviated like this if there wasn't room to print the whole thing.

author: David Chamberlain
author_rank: Frequent Contributor
timestamp: August 16, 2020, 12:57:58 am
content: Thanks for the explanation.Although, as listed, I did not find any parts with that prefix and the numbers "0636" or "0457". The parts I did find in the list were all the wrong package types so I rule them out immediately.I have now found1820-0457 02910 N8162N - is a Signetics part and images online suggest this was a DIP package.Cannot find refference this online.1901-0457 02062 QSRD-4652 - Manufacture "HP DIV 05 MSG"?? no idea what this is. HP Internal Division 5 perhaps?These HP codes work on the dip package in the image.. 1826-1076 = LF444CN Quad JFET opamp.I would guess the TO-92 parts are GP transistors of some sort, and the TO-5 can is an special high bandwidth opamp.

author: precaud
author_rank: Frequent Contributor
timestamp: August 16, 2020, 02:40:51 am
content: If you want to actually find the part, you have to accept that the prefix number ends in 4, and not look for anything else.To find the parts via Google, put the exact part number in quotes so Google only returns exact matches.such as: HP "1854-0457"returns:Part Number : 1854-0457 Manufacturer : HpDescription : Transistor-Dual Npn 0.4W To-78 Ththere's one on eBay for "only" $22.50:https://www.ebay.com/itm/Agilent-HP-1854-0457-Transistor-dual-NPN-0-4W-TO-78-THT-accessory-/351110020200There's less info on the "1854-0636", but it is used in the 8566B Sweeperhttps://archive.org/stream/hp_8566B/8566B_djvu.txt3314A, and others.TRANSISTOR NPN SI TO-72 PD=200MUNo cross given; may have been a selected part.I'l look tomorrow and see if I have either in the bins.

author: David Chamberlain
author_rank: Frequent Contributor
timestamp: August 16, 2020, 07:19:32 am
content: Quote from: precaud on August 16, 2020, 02:40:51 amSorry Precaud, I did a couple of things wrong 1) assumed the PDF from Sphere was complete 2) didn't actually check google for the numbers you suggested.1854-0457 -> Transistor-dual NPN 0.4W TO-78 THT1854-0636 -> NPN SI TO-92 PD=350MWAnd yeah $22.50 is a lot especially considering it's 1/3 what I paid for the entire scope.Having said that I don't know yet these parts are bad.Thanks again.

author: bd139
author_rank: Super Contributor
timestamp: August 16, 2020, 09:05:56 am
content: A lot of these parts are generic and a lot are selected by HP. I find that it’s best in these circumstances where it’s not well defined, to look at the schematic, the use case and the D.C. operating point and make an educated guess at a suitable substitute.

author: fzabkar
author_rank: Super Contributor
timestamp: August 16, 2020, 08:45:09 pm
content: Page 43 of this databook has likely candidates for 1854-0457 (dual NPN transistor, TO-78):https://mirrorservice.org/sites/www.bitsavers.org/components/motorola/_dataBooks/1987_Motorola_Small-Signal_Semiconductors.pdf1854-0636 is probably in that same databook.