Identify Diode manufacturer for notebook MB - Page 1
Forum section: electronics / general

author: Tyradius
author_rank: Newbie
timestamp: April 20, 2011, 01:15:38 am
content: I have an Acer notebook that I believe has a bad diode on it. The AC adapters led lights up just fine when not plugged into the system. Once it is plugged in, it dims and flashes really fast. Tried another AC adapter without success. Upon disassembly I plugged the adapter in with the board out on the bench, and used my fingers to feel for any hot components. I found this one, right next to were the DC jack cable is plugged into the board.I am trying to identify the manufacturer so I can find a datasheet on the part so I can see what type I need and find a replacement.I am new to component level tinkering, besides replacing dc jacks on systems. Because of that I am having a hell of a time finding the manufacturer, let alone exactly what type it is. I know the characters on the top of it mean something specific but I dont know how to read them, or were there are any sources to go to find the info.I feel that if I can get this part and replace it, that the system will work again. The way the power is acting its as if the diode failed internally and isnt allowing power through, causing it to heat up. Atleast that is what I believe it is.Thank you anybody that can help!picture attached below:

author: tecman
author_rank: Frequent Contributor
timestamp: April 20, 2011, 02:06:58 am
content: a14a is a valid part, 50v 3 amppaul

author: joelby
author_rank: Frequent Contributor
timestamp: April 20, 2011, 02:30:41 am
content: Have you tested the diode? Try measuring if there's a voltage drop across it.

author: Zad
author_rank: Super Contributor
timestamp: April 20, 2011, 02:49:06 am
content: A diode heating up would me more likely to be caused by a short circuit somewhere causing excessive load. The PSU will be sensing this and shutting down. It might be that the switching transistor has failed short circuit, or there is a component in the feedback loop with a dry joint causing the output voltage to rise too high, and operating the safety protection.Meter the diode. Youmaybe able to measure it in-circuit.

author: Tyradius
author_rank: Newbie
timestamp: April 20, 2011, 05:26:18 am
content: Thanks for the feedback. I will meter the diode. Also, I figured the a14a was the part number, but I guess my google-fu is lacking, because I could not find any data sheet on what an a14a is suppose to be, let alone find it on mouser or digikey. I will try again though. Thanks again!

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: April 20, 2011, 06:46:30 am
content: Quote from: Tyradius on April 20, 2011, 05:26:18 amIt's is not you, my friend. Google-fu should be Google F U.Has anyone else noticed how bad Google is for searching things now? Anything that you put in the search bar for tech info returns two pages of ads to sites selling the thing you've already got that you're having trouble with.

author: saturation
author_rank: Super Contributor
timestamp: April 20, 2011, 12:44:46 pm
content: Of topic for a tad, google searching is getting noisier; more commercial hits on the top tier pages rather than what you need. You can filter off .com to reduce noise, then limit searches within .edu , .gov and .org, org is the noisiest of the 3, second to .com.I don't know how long those low noise trends for domain suffixes filters will last.Quote from: Ed.Kloonk on April 20, 2011, 06:46:30 am

author: Tyradius
author_rank: Newbie
timestamp: April 20, 2011, 05:44:37 pm
content: I put the meter on the diode, it instantly goes down to 001. Switching the probes around does the same thing. I assume this means its shorted out? I did it while it was still on the board, with no power to it. Like I said before I am still new to all of this.putting power to it and testing reveals random readings from 220 upwards of 700 fluxuating. Switching the probes around show the same reading with a negative sign next to it.On a side note, when I said google-fu I meant it as a broad term to mean searching the internet.Because ive used Bing, Yahoo, and Google to no avail. I am on digikey right now trying to find the part, and I dont get an option for amps, and I dont know which parameter the 50v goes in. Searching the net reveales nothing on what a standard surface mount a14a diode's specs are even suppose to be. Are they all standard? If I could identify the manufacturer of this specific one, hopefully I would be able to find a tech sheet on it, even if its in chinglish, just to find out what the tolerances are. Are all a14a's the same? do some have tighter tolerances then others?I hate being a newb to new thingsand yes google does suck, Ive been using Bing more and more lately.