Proprietary Laptop PSU ??? - Page 1
Forum section: electronics / general

author: han
author_rank: Frequent Contributor
timestamp: March 01, 2014, 10:05:47 am
content: Hi all,I buy a cheap laptop PSU from amazon for make cheap switching variable power supply.And after open it i'm wondering what the signal wire do? (don't turn it on take it apart ??)Is there anyone decode the signal pin function in the 3 wire PSU?PSU type is Delta Electronics ADP-65MH B 65 Watt.http://www.amazon.com/Genuine-Delta-Electronics-ADP-65MH-Adapter/dp/B003K8Y36G

author: neslekkim
author_rank: Super Contributor
timestamp: March 01, 2014, 10:48:14 am
content: something like this?http://dangerousprototypes.com/2014/02/27/spoofing-wattage-info-from-a-dell-power-adapter-with-an-msp430/

author: mariush
author_rank: Super Contributor
timestamp: March 01, 2014, 10:49:43 am
content: If I remember correctly, the Delta power supplies had a 1 wire eeprom with some data that signals to the laptop the wattage of the adapter (and the fact that it's genuine). This way the laptop can go to "reduced power" mode when battery low and running from a 60-65w adapter, or go to high power mode when a 90w adapter is plugged.

author: han
author_rank: Frequent Contributor
timestamp: March 01, 2014, 11:02:48 am
content: Hi,updateI just probe using two multimeter,the outer jack is using two conector : Ground and signalIner is Vo,with signal unconnected:Vo-Gnd voltage : 0.5VWith signal shorted to GND:Vo-Gnd voltage : 0.5VWith signal shorted to Vo:Vo-Gnd voltage : 0.5VBut when i bias the Signal to ground using (fluke 87 diode tester):Vo-Gnd voltage : 18.8 Vsurprise surprise...

author: fluxcapacitor
author_rank: Frequent Contributor
timestamp: March 01, 2014, 02:25:15 pm
content: the 1 wire chip is/was a dallas 2501 .http://jack380.wordpress.com/2009/03/06/how-to-solve-the-problem-dell-ac-power-adapter-type-cannot-be-determined/http://www.laptop-junction.com/toast/content/inside-dell-ac-power-adapter-mystery-revealed

author: maikelmox
author_rank: Newbie
timestamp: May 10, 2015, 11:31:05 am
content: It is clear that the power brick is expecting the signal from a battery (at least partially loaded) at the laptop end.I have the same problem as you. The PSU is rendered useless unless I can feed some voltage, preferably taken from some point at the output stage of the same PSU, into the sense pin.Did you succeed at this? If you did, it will help me a lot to get your suggestions.Kind RegardsMiguel

author: amyk
author_rank: Super Contributor
timestamp: May 10, 2015, 12:59:28 pm
content: I looked at the schematic of one of the laptops (Acer Aspire 1640/Quanta ZL8) that this PSU is supposed to be for, and it has only a two-pin DCIN with no additional sense/signal wire.Perhaps it needs to be plugged into the right jack - it should be a 2DC-S726I201.

author: maikelmox
author_rank: Newbie
timestamp: May 10, 2015, 03:04:14 pm
content: I figured out a way around the battery voltage sensing.By the way, there seems to be more than one model of this PSU in the market. For models with just 2 pin output and no battery voltage sensing you can ignore this advice, you should be getting aprox. 19V DC output at all times without issue .If, like me, you have the three pin version and want to use this PSU for something other than an ACER laptop you can try this. WARNING! Do it at your ouwn risk and only if you understand what you are doing.There are two optocouplers on board that feed back information from the low voltage (19V DC) to the high voltage (mains 230V AC rectified to 380V DC) side of the transformer while maintaining isolation between them:1- on the top side (transformer mount side) there is the one that feeds back the info on secondary voltage to the controlling IC, leave this one alone as you need it for regulation of the voltage output.2- on the copper pads side there is a second optocoupler labeled IC33 between two black adhesive rubber spacers (see photo by HAN in one of the posts before), this is the one that tells the controlling IC to power OFF the output when there is no voltage level feedback from a battery, if you short the two pins of the optocoupler ON THE HIGH VOLTAGE SIDE you will disable this function.After you disabled optocoupler #2 you should get around 1V DC output, you can feed this directly to the sense pin and the PSU will output the full 19V DC. It seems there is some circuitry on the output side also requiring a battery voltage sense feedback to operate.Disclaimer and warnings:- This process may disable also some other performances (i.e. output overcurrent/overvoltage protection). I have not taken the time to reverse engineer the circuit well enough to know this; I am willing to take the risk for me but I will not accept any responsability for what others do with this info.- The big 400V capacitor on the high voltage side remains charged for a long time and can zap you badly if handled without care, even if the unit is not plugged. It hurts!- If you do not understand my explanation above you should NOT be attempting any of this.

author: bunsoft
author_rank: Newbie
timestamp: February 23, 2017, 11:54:40 am
content: Hi Guys,Sorry for posting here, i know is old topic. I just received a supposed to be good PSU and as the other persons from this topic i want to use it as a standalone PSU.I tried the steps given by mikelmox but still not able to start the PSUAfter bridging the optocupler i get at the power on moment 3V and it goes down slowly to 0.5V in a couple of seconds.I read in this topic that the PSU is expecting voltage from battery. I think the voltage signal comes from the laptop itself not the battery because the laptop can operate without battery inserted with AC plugged in. I think this signal wire is saying to PSU to shut itself down if laptop is turned off.I will try the signal vire biasing with the multimeter as han done. to see i this thing works or not.Wishing you all a nice day.With regards,B.

author: bunsoft
author_rank: Newbie
timestamp: February 23, 2017, 02:05:22 pm
content: Update.After playing around, i can make the PSU work if i feed the sense wire with 1.5V. i used a AA battery to do it and it looks like it is working.Now i have to find a component inside which has always power.For some reason bridging the optocupler does not give me a steady 1V output, it goes down to 0,5 after a minute or two.Wishing you all a nice day.With regards,B.

author: james_s
author_rank: Super Contributor
timestamp: February 23, 2017, 07:04:41 pm
content: Quote from: mariush on March 01, 2014, 10:49:43 amI'd wondered how that works. I have a few older Lenovo laptops and the bigger one will notify me if I plug in the adapter from the smaller one, and they display the wattage of the connected AC adapter. I never investigated in depth how this works but I bet it's something like this.

author: Monkeh
author_rank: Super Contributor
timestamp: February 23, 2017, 07:08:43 pm
content: Quote from: james_s on February 23, 2017, 07:04:41 pmLenovo use a resistor between the centre pin and ground.

author: james_s
author_rank: Super Contributor
timestamp: February 23, 2017, 07:12:41 pm
content: Interesting, thanks. It's one of those things I noticed and wondered to myself how it works but never got around to looking into it.

author: Monkeh
author_rank: Super Contributor
timestamp: February 23, 2017, 07:15:21 pm
content: Quote from: james_s on February 23, 2017, 07:12:41 pmThis article lists nearly every connector and ID method used on Thinkpads at the least:http://www.thinkwiki.org/wiki/Power_ConnectorSome other Lenovo laptops may use a different mechanism, but most I've seen have been generic DC jacks. This freakfest being an exception: