Thinkpads Forum

After involving in a different thread here, I decided to look into recelling one of my dead 360Cs batteries. So when I took the 360 out of its bag anyway, I decided to give it it's annual boot up, only to see that it died after a minute. Luckily it turned out to be the power adapter that gave up. During troubleshooting the adapter came back to life for a while, so I verified that the laptop hadn't suffered any injury from it.

So I started sourcing a new one. It has the old square plug with 4 pins, and it's 20 volt. But when I search on eBay, the adapters that comes up for the 360 are listed as 16 volts. Like this one:http://www.ebay.com/itm/221120361066

Then I did a search for the part number on the back of my adapter, and I found this one:http://www.ebay.com/itm/310691908284 It is identical to the one I have, and it's an IBM adapter, but the description doesn't say what it's for.

I do however remember that 12-13 years ago, while I still used the 360Cs for an ancient PLC at work, the power supply broke, and I found another one that I think came from an older Thinkpad. Have I been using a wrong adapter all these years? Can any of you verify which one is the correct one, so I can purchase one?

Thank you for any help!

Admin edit: Shortened URLs

According to the tabook of the day, the 360Cs came with a "wallmount AC adapter without power cord with retractable prongs, 30 watts". No explicit FRU is given for the adapter. Looking at the HMM the covers the 360 series, there's one AC adapter for the US: FRU 84G2277 (120V only). There's currently three of these on eBay. The Power Checkout section says to expect 20VDC across pins 1 and 2:

+-------+
| 2   x |
\       /
 \ 1 x /
  -----

1: +19.0 to +21.0
2: Ground

Look around on the 360Cs for a label that says what the voltage input should be and that should tell you which adapter you can use.

Thanks! I guess your last sentence made me able to verify this 100%. - Look for a label.

I examined the 360Cs this morning, and when I looked carefully at the area above the connector, I could see signs of something that had once been printed there. It was a pin layout of the plug, and it said 20 volt. So it seems as the 20 volt ones are the correct ones. Don't know what's up with the advertised 16 volt ones, but that's not my business.

So this really wasn't as simple as I thought. I am still at a loss here, as the 3 adapters you mention rkawakami, are 120 volt in, and can't be used here, as we have 240 volt. Further, the two 20 volt adapters I found are either cost prohibitive ($70 price tag for shipping) or doesn't ship to Norway at all. The 16 volt adapters are easier accessible, and they are all described as being compatible with all 360 series Thinkpads. To further add to the confusion,Thinkwiki describes the power adapter for the 360 series to be 15V, 2A: http://www.thinkwiki.org/wiki/Power_Con ... _connector

So my final question is: Can anyone with a working laptop from the 360 series (360, C, CE, Cs, CsE) check their power supply and let me know what output volt rating it has? And even better: Can anyone explain where the 16 volt adapters comes into the picture? Are they a later upgrade for the 20 volt ones?

Regarding thinkwiki, it doesn't say anything about the 360 series actually; it's under the "Unknown watts/amps" category. I've personally added the 360PE under the 20 Volt 2.5 Ampere category having communicated with Tasurinchi since he owns one http://forum.thinkpads.com/viewtopic.php?f=21&t=109967

So, if someone comes forward with any info, I may update the wiki as well...

Think I found someone we could ask : http://www.ebay.co.uk/itm/IBM-Thinkpad- ... 1157704736

Ok, as it said "Unknown watts/amps",I thought the voltage was known, ie 15 volt.

Anyway, the one for sale in the ebay link should be ok for me, as UK uses 240 volt. I have sent the seller a message to confirm it is listed with 240 volt AC in and 20 volt DC out. AND that he ships to Norway.. If not, I hope I can ask someone in here to buy it and pass it on for me.

Norway Pad wrote:To further add to the confusion,Thinkwiki describes

There was a notice, informing readers that the contained information is incomplete and inaccurate; but it was removed four years ago. Maybe, that notice should have remained for a longer time. The article is not perfect. It upsets me. I spent a considerable amount of time trying to improve accuracy and provide facts. There were several mistakes in the past, but now, I think, the article is mostly correct yet incomplete.

You can help. I did not yet, come across any report or any person try to measure the signal pin, of the old hexagon plug. See if there is a simple resistance to ground.

automobus wrote:You can help. I did not yet, come across any report or any person try to measure the signal pin, of the old hexagon plug. See if there is a simple resistance to ground.

I can sure do that. Bear in mind that my supply is broken, so this pin might not behave like it's supposed to. But I will try to measure the signal pin tomorrow and report back. I will repeat the operation when I get a new one.

Edit: After extensive searching, I found adapters for sale on the German eBay site. So I bought two of them, as my 360 has already eaten two of them before. These parts will probably not be easier accessible as the years pass by. I will also do some research on the pin configuration, and hopefully report back to autombus and Thinkwiki.

Following the postings in this thread, upon request from Autonombus, I did some measurements on one of the adapters I bought. There were, and still is, some uncertainty what the purpose of the Signal pin is, and I don't know enough about electronics to do more than some educated(?) guesses. Another point of confusion is that these adapters are listed as both 10 and 20V DC. The laptop (Thinkpad 360Cs) itself is labeled as 20V.

The hexagon power plug has 4 pins: +, -, S (Signal) and G (Ground). It is taken for granted that + and - is the potential / current used to run the laptop, while I wasn't sure about S and G.

For G, it quickly became apparent that this is simply the Ground pin from the AC power plug carried on through the adapter. It has no direct connection to -, as the resistance measured between these two is in the Mega-Ohm range.

For +, - and S, I opened up the adapter to get access to the solder points where the leads for these pins are connected, so I could measure while the plug was inserted in the laptop and the laptop was turned on. Between + and -, the voltage level was directly below 20V. The first time I turned on the laptop, it was 19.94V, the second time it was 19.96V. Natural fluctations? Probably so. The S pin carries a positive voltage which is fed from the adapter, as a voltage is present when it isn't plugged into the laptop. When the laptop was turned on, I measured 21.0V between S and - the first time, and 21.02V the next time. So the 0.2V fluctation also affected the Signal voltage. The second time I had my wife operate the laptop while I measured between S and -, and operating the laptop seemed to affect the S voltage level:

First: Changing the brightness/contrast up and down changed the Signal between 20.99 to 21.06V.

Second: She opened up AutoCad, which made the harddrive grumble for a while, and probably also triggered CPU activity. What I noticed then, was that Signal voltage changed with the grumbling from the drive. It alternated between 21.16 and 21.25V while this was going on. After that it fell back down to 21.06V. At that point I had altered the brightness/contrast settings, which made it permanently stay at 21.06V. I also tried measuring + / -, and that was stable at 19.96V during the entire startup of AutoCAd. Then I tried measuring Signal and open AutoCAD one more time, and it still fluctuated between 0.1 to 0.2V above it's "idle" level. So basically, + and - was stable, while S was varying.

After doing this research, I was rather left with more questions than conclusions.

- Is S a voltage regulating pin, as the voltage varies with the "load"? I think not, as that means that voltage regulation would have taken place inside the Thinkpad, and not in the adapter. But I can't say it for sure.

- Is the S simply a trickle voltage, that checks for connectivity, and tells the adapter that a laptop is connected? If so, what happens if S loses it's connectivity? Can the laptop cut the connectivity, or is S a monitoring voltage that dies if something happens to the adapter? One major limitation of my experiment is that fact that the 360Cs is a collectible, and I didn't want to do any potentially "destructive" testing. If this had been one of my numerous T4x machines, I would simply have cut the Signal wire to see what had happened. But I don't dare do that with the 360.

- Can S have anything to do with battery charging? I have no working battery for the 360, so I have no way of testing with a battery installed.

- And why is the adapter listed as 20 and 10V, when I couldn't find any traces of 10V? Can the laptop change the voltage level through the S pin?

Autonumbus has asked for this posting for a while now, so I expect him to make some comments. And if someone has it in them to open up and do some research on my failed adapter, I offer to ship it to them, free of cost. The offer goes for EU, and the US.

Edit: The original purpose of this was to see if maybe another 20V adapter, without the Signal pin, could be used instead of the original adapter. That question is still unanswered, as I don't dare messing trying to connect 20V on +/-, without the Signal connected.

Just in case:
I have such an adapter sitting here, gathering dust.
It's got the 4-pin connector (four "+" openings).
It has these markings:
P/N 29H6704 and FRU 49G2196
Model AA19210
Input: 100-240V ~ 0.95-0.5A, 50/60Hz
Output: 40 Watt max. 20V-2A / 10V-3.38A

My research found it is compatible with: 350/360/370/380 and 750/755/760/765
Looks like this:


You can have it for shipping cost to either USA or Norway.

Thanks for the offer, this is the same one as I have. I actually found two adapters in Germany, and bought both of them. Good to have. They don't seem to be too durable, as my 360 has already blown 2 of them over the years. So I might have you do a SATA conversion in the near future, and maybe this adapter comes back with the board? I will PM you about it.

Thank you, Bjorn, for your time and effort to experiment. I appreciate it very much. A reminder to readers: regarding these vintage AC adapters in ThinkPadLand, the S pin is referred to as: S, SIGNAL, or INPUT SIGNAL.

Here, I modified Ray's ASCII illustration.
  _____
 / S + \ OUTPUT PIN ASSIGNMENT
| G   - |
+-------+

  _____
 / + S \ DC INLET
| -   G |
+-------+

Norway Pad wrote:operating the laptop seemed to affect the S voltage level:
First: Changing the brightness/contrast up and down changed the Signal between 20.99 to 21.06V
…
So basically, + and - was stable, while S was varying.

After I read your reported observations, I wondered if S means 'POWER GOOD'.

I thought, it could be like a canary in a cave mine. Assuming S is a place in PSU circuitry, before all of the conditioning of + output, it is of higher potential level, because filtered and regulated and such. Assuming in the event of some fault, capacitors can sustain potential of + while S drops. If S is approximately 1 volt above + : good. If S is equal or below + : bad.

Norway Pad thought, it could be a signal whose meaning is same as in Intel PC power supply (ATX, and its extensions and derived form factors). + must reach stable level, and all internal conditions okay, before asserting POWER GOOD. Maybe, without S, ThinkPad will not start. I like this idea, more than my canary idea. See also: ThinkPad T20 'Blink Of Death' BoD.

In a private message, Norway Pad wrote:If we go down the On/Off route, and use logic: Any internal failure in the adapter causes the SIGNAL to go down, and it shuts the laptop down even if 20V is still present on the main leads. It can even shut something off inside the laptop, to prevent any harmful power spikes / low voltage from the adapter to do any harm to the laptop. Before switching adapter technology got as refined as it is today, maybe they had little or no control over what the adapter did when it failed, and SIGNAL was a safety measure to prevent it from damaging the laptop?

An argument against this hypothesis comes from ThinkWiki user Cloudane, who wrote about a replacement plug hack. It seems that SIGNAL pin is not needed for operation of at least some unspecified ThinkPad model, and at least to run without charging.
http://www.thinkwiki.org/wiki/Power_Con ... _connector

Norway Pad wrote:Can the laptop change the voltage level through the S pin?

I too, wondered about this. I assume these are variable output supplies. If at least one old model used 16V from the hexagon, maybe another model used 10V? Perhaps this is pulled-down with a voltage selection device. That would explain why PSU label says INPUT SIGNAL: It is the reference potential, input used by voltage regulation circuit. I can imagine, S is not connected, not used at all, by some ThinkPads. Because it is left floating, S can vary, as Norway Pad observed rising higher than 21 V.



About power levels: twbook.pdf indicates certain models having such-and-such watt supplies, but I find eBay photographs of underside labels, marked 50 watt. I assume certain hexagon-plug ThinkPads can draw 50 watts max. when charging battery, but that is more than needed. They can operate, and perhaps charge battery more slowly, with a lower nominal power rating. They will never draw more than 50W. Is this believable?



About Norway Pad's failed bricks: I do not blame them for being overworked and under-rated. Rather, I suspect they are aged beyond design lifetime, fatigued and worn out-of-spec. Perhaps they are now damaged, perhaps fuses or something are blown. Perhaps, if capacitors were replaced with fresh newer technology parts, then failure could have been avoided.

I found interesting specifications in ThinkPad Power Series 850 Hardware Maintenance Manual. It is a good read, as technical writing goes. It sheds more light than the average HMM.

Hardware Maintenance Service and Reference 30H2383 ThinkPad Power Series 850 First Edition (July 1995) wrote:AC Adapter
Output Voltage
• Operating mode: +20 V dc
• Charging mode
- Minimum: +9.0 V dc
- Maximum: +16.0 V dc
Maximum Current
2.50 A

Quick Charger
Output Voltage
- Nominal 12 V dc
Maximum Current
2.7 A

AC Adapter Test

Measure the output voltage at the AC Adapter plug between pins 1 and 3.
  _____
 / 2 1 \
| 4   3 |
+-------+
Pin Voltage (V dc) Signal Name
 1  +17.8 to +21   dc output
 2                 VCCSEL# (VCCC mode select signal)
 3  dc ground      RTN
 4                 COMMGND (Type-1) Open (Type-2)

For a moment, I thought COMMGND is 'communication ground' (COM sometimes refers to serial communication port), but soon I realised it must be 'common ground'. I do not know what 'VCCC' means. Maybe ThinkPad 850 is not capable of Computer Power On operation and battery charging simultaneously.

If it is true that some ThinkPads can either Power On or charge battery, then perhaps S is signal sent from ThinkPad to AC Adapter to select its mode. In power supply mode, AC Adapter outputs +20 Vdc. In battery charger mode, battery is connected direct to power inlet, perhaps through relays or other method, with no charge control/voltage reduction performed by ThinkPad itself. I doubt this.

I suspect Quick Charger (FRU of two models is 84G9870 84G9871) is a Type-2 AC Adapter.

Dear Automobus,

While you are at it, could you please correct the picture for 700T? The one on site is of 710T, not 700T

http://www.thinkwiki.org/wiki/Category:700T

Here is a correct picture:

http://cdn.slashgear.com/wp-content/upl ... edComp.jpg

And I have several (4 or 5) of those adapters and some say 20V and some 16V. One which came with new in box 750P is 20V, so I am a bit confused here as well

automobus wrote:It seems that SIGNAL pin is not needed for operation of at least some unspecified ThinkPad model, and at least to run without charging.
http://www.thinkwiki.org/wiki/Power_Con ... _connector

This might be correct. Cloudane did not mention charging. Perhaps Car-Battery Adapter (49G1148) does not use S, so when ThinkPad does not get a signal, it does not attempt to charge while powered-on.

However if 765 needs 16V, then it cannot use S to select 16V (by pulling-down from 20-21) when S is not present. Maybe 765, which operates from nominal 16 volt, can operate also from 20 volt.

IBM Mobile Systems Hardware Maintenance Manual Volume 4: ThinkPad Computers September 1997 S05L-1270-01 wrote: ThinkPad 765D (9546), 765L (9547)
Checking the AC Adapter:
Voltage (V dc)
+15.5 to +17.0

Checking the Car-Battery Adapter
Note: The Car-Battery Adapter does not charge the battery pack when the computer is powered on. This is not a failure of the Car-Battery.
Voltage (V dc)
+19.0 to +21.0

edit 2016-03-02 add:

automobus wrote:About Norway Pad's failed bricks: I do not blame them for being overworked and under-rated. Rather, I suspect they are aged beyond design lifetime, fatigued and worn out-of-spec. Perhaps they are now damaged, perhaps fuses or something are blown. Perhaps, if capacitors were replaced with fresh newer technology parts, then failure could have been avoided.

Gough Lui recently examined a failed AC adapter power supply. His report includes large close-up photos of the broken device. His example explains how one bad electrolytic capacitor can cause damage to circuit components other than fuses. Failed: Linksys/Cisco PAP2T Power Adapter (AD 5V/2F PSM11R-050) Posted on February 20, 2016 by lui_gough