Please help me identify this diode? - Page 1
Forum section: electronics / beginners

author: Acedias
author_rank: Newbie
timestamp: March 23, 2019, 08:24:20 pm
content: Hello everyone,I am helping a friend with a power door lock issue on his car. We narrowed it down to the control unit under the dashboard that controls the power locks as well as power windows and ignition lock. I began by removing components out of circuit one by one and testing them. Capacitors, resistors, then diodes. Everything tested ok until i got to this diode. It is reading bad both ways using my meter.Luckily all the diodes on the board seem to be the same. All have the same identification on the side, but i have had no luck with finding a replacement using the numbers.I need some help identifying this diode.On the side it has 0139 or possibly 3901 Or 01 3 9 depending on how you look at it.The 01 goes one way and the 3 and 9 are turned the other way. (Attached pictures)The others seem to measure anywhere between .570 and .593 vdc on my multimeter set to the diode test.Any help and guidance would be appreciated.

author: floobydust
author_rank: Super Contributor
timestamp: March 23, 2019, 09:22:12 pm
content: I would say it's a Japanese part, non-JEDEC package. Possibly "R1" but you'd have to measure yours.It's usually a vanilla rectifier diode rated 1.5-2A, skinny leads (small PCB holes) and smaller body. It all makes it hard to find a replacement in NA where everything is DO-41 and 1A or 3A with nothing in-between.

author: Jwillis
author_rank: Super Contributor
timestamp: March 23, 2019, 09:57:14 pm
content: The DO-41 ( DO-204-AL or SOD66) is a common semiconductor package used to encapsulate rectifier diodes.Typically 1N400X series.Best guess it's equivalent to 1N4001.

author: Spork Schivago
author_rank: Frequent Contributor
timestamp: March 24, 2019, 01:12:26 am
content: Could you provide a picture that shows where sideways letters meet the normal one, perferable one that shows most of the numbers on the diode?Also, is there any numbers on the board itself? Such as a model number of the board? Probably a long shot, but sometimes, I can find schematics for various equipment.Thanks!

author: Brumby
author_rank: Unknown
timestamp: March 24, 2019, 02:42:54 am
content: Quote from: Spork Schivago on March 24, 2019, 01:12:26 amYou can work that out by looking at the top right image. The top of the "3" is just visible.QuoteYou aren't going to get a single shot showing that, without some very clever optics - or some photo stitching.

author: Acedias
author_rank: Newbie
timestamp: March 24, 2019, 03:07:35 pm
content: This one may give a better idea of the number layout on the diodes.

author: Acedias
author_rank: Newbie
timestamp: March 24, 2019, 03:19:19 pm
content: Markings as follows:(Outside casing)Theft warningToyota89730–14030MW-8350(Circuit board)MW-<8350>, (8380) , Sent from my iPhone using Tapatalk

author: Spork Schivago
author_rank: Frequent Contributor
timestamp: March 24, 2019, 05:04:26 pm
content: Quote from: Brumby on March 24, 2019, 02:42:54 am

author: mfratus2001
author_rank: Contributor
timestamp: March 24, 2019, 06:14:19 pm
content: It could be a 39 Volt Zener diode. Looks like an input/output protection job to me.

author: floobydust
author_rank: Super Contributor
timestamp: March 24, 2019, 09:04:21 pm
content: The diodes are for the digital inputs going to the MCU. Toyota uses them to "OR" with other (car) signals and to protect against voltage spikes and the reverse-battery scenario. The cathodes go to the car's switches/inputs, and the resistor packs are pull-up resistors for the MCU.It's not a small signal diode because the "OR" can involve dashboard lights or external relays.The original part I think is made by Fuji or Panasonic, ERA15 series (ERA1501, 39 is mfgr. week). This is oddball package small 3mm 1A or 1.5A general purpose rectifier diode, 0.6mm leads. A zener would have a "Z" in the part number, per JIS standards.I would stuff in a 1N4004 or higher voltage part. Because they are bigger 5mm wide parts with slightly fatter leads, the repair is never going to look pretty unless you sharp bend the leads.If you want a diode in the same original small package, I have only seen them in inverter microwave oven control boards, consumer electronics or other Fujitsu Ten modules.If the new diode blows, then there could be a short with whatever else connects to other module pins as part of the OR gate function.An example is interior lights can be on due to the door switches OR the console switch. The door ajar annunciator is only on due to the door switches, so Toyota uses diodes there. Otherwise the door ajar annunciator is lit but you just manually switched on the interior light and your doors are closed.

author: Jwillis
author_rank: Super Contributor
timestamp: March 24, 2019, 09:12:34 pm
content: Its a Sanken general purpose rectifier diode probably an AM01 the 39 is a date code.

author: Acedias
author_rank: Newbie
timestamp: March 30, 2019, 12:28:51 am
content: Thanks to everyone for the help and suggestions. I have ordered some parts and hopefully should have it working soon.Sent from my iPhone using Tapatalk