Unknown part - Page 1
Forum section: electronics / general

author: shock__
author_rank: Newbie
timestamp: September 15, 2018, 12:39:24 pm
content: Hey there,I'm currently in the process of partially reverse engineering a stamped card reader and stumbled upon a part I can't exactly verify.The PCB the part is on can be dated to early/mid 70s and was at least designed in Germany.Any ideas?

author: madires
author_rank: Super Contributor
timestamp: September 15, 2018, 01:54:07 pm
content: An image with a higher resolution would be helpful. At first glance it looks like a broken resistor. Have you checked it with a DMM?

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 15, 2018, 02:17:35 pm
content: Looks to be a diode, which says 141, 242, 343, 747. Poor resolution an poor colours. Please resend.

author: shock__
author_rank: Newbie
timestamp: September 17, 2018, 04:34:34 pm
content: Here's a better picture, a friend of mine who often works with vintage (analog) electronics told me it's a "flyback/recovery diode" (Freilaufdiode in German) which would make sense as it's connected to a relais.Picture was taken with flash activated on my smartphone (which is the best I can offer). Size is slightly smaller than a common leaded resistor for signals (0207?).Also attached is the (partial, temporary) schematic I got so far, U1 and U2 are the parts in question, the green line underneath corresponds with what I interpret as the "white marker" for the cathode.

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 17, 2018, 05:49:09 pm
content: Oyes that's a diodeAn 1N400X will do fine here.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 17, 2018, 06:38:41 pm
content: Maybe a 1N141. The 1984 Fairchild Databook says that a direct sub is the 1N4148.See another version in the datasheet here:

author: gbaddeley
author_rank: Regular Contributor
timestamp: September 21, 2018, 06:58:37 am
content: QuoteBrown Yellow Brown = 141 ??

author: Beamin
author_rank: Super Contributor
timestamp: September 21, 2018, 03:26:02 pm
content: Why do they have U2(diode?) across 74LS00N a nand gate? Wouldn't that feed back on it self? If the | on the schematic indicates the neg side of the diode wouldn't that mean when the first (top) pin is high it and the bottom pin is high it sends out zero. But if you put a diode on the output as a wire/bridgeto input 2 it can't turn on because it would then see that pin 1 and 2 are different? I'm confused it seems like that set up would make it never turn on.What does that circuit do?Datasheet of that part:http://ecelabs.njit.edu/student_resources/datas/74ls00.pdf

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 21, 2018, 08:25:08 pm
content: Because it's not a multiplier band.Quote from: gbaddeley onTodayat 01:58:37

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 21, 2018, 08:34:18 pm
content: Why is if followed by the?It's all about the reference. I don't see a schematic.Quote from: Beamin onTodayat 10:26:02

author: gbaddeley
author_rank: Regular Contributor
timestamp: September 24, 2018, 07:32:19 am
content: Quote from: gbaddeley on September 21, 2018, 06:58:37 amQuoting my own post, the '??' mean I am questioning: Was it identified as IN141 by reading the colour bands?