Thinkpads Forum

I've got a 90 W AC adapter that has the strain relief damaged, and the connection to the laptop is now intermittent.

I'd honestly rather repair this adapter than buy another one - Lenovo wants a bit more than I'd like to pay, and I've seen the Chinese knockoffs literally go up in flames.

So, is there a source for JUST a new DC cable that I can solder onto the thing, other than buying a knockoff on eBay and taking the cable from it?

I kind of doubt that you could find the original manufacturer of the DC cable. The company which sources the actual power adapter to Lenovo (i.e., simply brands the adapter with a Lenovo label) may not even be the maker of the cable. Don't have my own 20V adapter handy but I believe it has an in-line choke on the laptop side so you can't (shouldn't) use a cable without one (could introduce noise issues with your system or surrounding equipment).

Assuming that you are mechanically and electrically knowledgeable about the dangers of fooling around with 120V circuits, then you could consider simply cutting off the problematic section of cable (I'm assuming from your description that it's right next to the adapter), stripping back the insulation, forming your own strain relief, since that portion of the cable is being eliminated, and soldering the correct leads back onto the adapter's circuit board (lest you reverse the polarity and blow up your laptop or short the connections and blow up the supply).

All-in-all, your best bet might be to scope out eBay and hope for somebody unloading a supply for "cheap". I see several for around $25 or less (includes shipping to the US). Ignore the adapters that have "For Thinkpad/IBM/Lenovo" printed on the label, as well as "Replacement for....". Compare the label on your existing adapter with the ones in the auctions and you should be able to screen out the Chinese knockoffs. Look for logos, trademark symbols, FRU number, barcode labels, etc. Realize however, that most genuine adapters are also made in China .

edit: Also check the color of the Velcro® strap. If I remember right, the 20V adapters should be light gray (as opposed to black).

I'll probably just use a knockoff adapter for its cable.

I got this adapter used, because I didn't feel like sifting through every knockoff adapter to find a cheap new genuine one.

My cable is failing at the laptop end, not the adapter end. And, this is the 20 VDC cable, not the 120 VAC cable (which is easily replaceable, just unplug, and plug new one in.) While there are 120 VAC dangers with the thing opened, I know better than to open it while plugged in, and I know not to touch the terminals on the caps.

I have taken a faulty adapter apart to see what makes it tick. The chances of properly replacing just the DC cable are probably quite slim.

And from the peanut gallery here (along with yards of experience), I do NOT recommend a cheap knock off adapater. Get the correct one for your machine for good long term reliability.

I got a 20V adapter here (thinkpads.com) for my T61 for a very reasonable price. Brand new and works a treat. ... JDH

bhtooefr wrote:is there a source for JUST a new DC cable that I can solder onto the thing, other than buying a knockoff on eBay and taking the cable from it?

Not as far as anyone has been able to determine so far.

Cheers,

Bill B.

I had this issue with the adapter for my old Toshiba M200 tablet pc. The outer plastic (or rubber) sheath broke near where it meet the plug (which went into the laptop). I used some "Tent Repair Epoxy" which came in a grab-bag of stuff I ordered form cheaperthandirt.com. It's basically a 2 part epoxy that dries mostly clear and remains flexible. I smeared it around the broken connection, and the cable is now good as new. Since your cord works intermittently, it sounds like one of the conducting wires is frayed too. You may be able to get some electrically conductive glue (also known as "no heat solder") in there to repair the connection before epoxying over the sheath for strength. Good luck.

PS: Since this is on the 20v side, you don't need to worry about much, it won't electrocute you. The greatest threat would be from creating a short-circuit in between the conductors and cause the cable to over heat. It would be rather apparent if this happened though, as the short circuit would prevent the laptop from charging, and you would notice this right away.

Go to the likes of Radio Shack and buy a new barrel plug. Cut off the bad part of the 20V cable and put the new plug on. Before plugging it in your laptop, check with a multimeter, that you have connected the positive (+) to the middle pole of the barrel plug.

20V plugs, as far as I know, have a "pin" and "wall" connection inside the barrel. I don't know if you're going to be able to find something like this at Radio Shack:

http://www.kawakami-ca.com/images/20v_dc_plug.jpg

It's not like the older coaxial plugs where there's only two connections; the metal sleeve outside the barrel and the hole at the tip.

I may have found a source for the whole cable: http://dcplug.net/ibm.html

Nice find! That indeed looks like the proper cord. It even has the strain relief, Velcro® strap and choke. At about 1/2 the cost of a new adapter, I'd only take this route (replacing the cord) if the adapter was put together with screws; a slim chance probably. That's about the only way to guarantee operator safety and retain visual neatness (not have Frankenstein scars from the epoxy holding the shell of the adapter together).

Excellent find.

Myself, I don't mind if my power adapter looks ugly, and I know how to not kill myself, so I'll just use that. I'll give it a day in case a cheaper source is found.

RealBlackStuff wrote:I may have found a source for the whole cable: http://dcplug.net/ibm.html

I placed an order with that web site for one cord a few days ago, at the offered USD $18 price including international shipping, which they accepted and allowed me to check out via Google Checkout.

Today I received an email that they had cancelled the order for no evident reason, and refunded the credit card charge.

Anyway, I recommened being very wary about this company.

Cheers,

Bill B.

huh.....just 5 minutes ago I posted in the "60-series" forum looking for a source for these plugs (not cables)....then 5 min later I find this thread...

These cables generally fail at the laptop-end, not the PS-end. The strain-relief design is poor...inadequate for a device that's moved frequently.

Regarding the "knockoff" power-supplies, let us remember that Lenovo's own PS is also made in China....and likely at the same firms making the 'knockoffs'...

I've owned a dozen "cheap chinese" switching power-supplies for the past 10 yrs. 2-3 of them have died and gone to parts-bin heaven....a few haven't been run enough to make a valid report on....and 2-3 of them have been running under load 24/7 for the past 6 years and are still doing it right now.

I couldn't program C++ to save my life, but I did design PWM switching power supplies and motor-drivers for 30 years; so this aspect of PC's is 2nd nature for me.

When I buy a PS, I look for the most detailed specifications, and also for individual specs that look like an engineer actually thought about it and checked it.

For example, instead of "Input; 12vdc"....I look for "Input Voltage Range; 10-15.5vdc". Devices I've bought that were spec'ed like that have generally turned out to be higher quality than otherwise.

Bottom-line; I've had as good a luck with 'knockoffs' as I've had with 'oem' PS over the years.

Random Note; Both the original Lenovo and the 'knockoff' cables are pretty darn light-gauge for the current and length involved, imho as a power-electronics engineer for 30 yrs. ...if I were replacing the whole cable, I'd make up my own new cable with heavier gauge wire. Less loss in the cable will let the PS run at lower output, and therefore a bit cooler. And these 60-series supplies run da*n hot, if you ask me.

Combining high density (small) with a zero ventilation (sealed case), and making the case out of -plastic-.....sheesh....poor design practice. If they wanted it small and totally sealed to keep dust out, they should've made at least one panel of the case out of finned aluminum to conduct some heat to the outside. Life of electronics drops by HALF for every 10-deg C increase of operating temp.

Anyway, here's another firm offering 60-series cables, who just sent me an email yesterday:

Miss Donly Yuan
Email: kuotong@yahoo.cn
Tel:+86-0769-81865780
Fax:+86-0769-81865791

I don't know if she'll sell one, or only lots of 1,000....you'd have to ask her.

Repairs: I've fixed a number bad plugs like this by cutting away the molded plastic around the back-end of the plug, resoldering the cable on, and "remolding" the back end with either high-durometer silicone or 'flexible' epoxy. I have not found regular 'hard' epoxy to work very well in this application. Actually, despite the low-tech name, I have found "Automotive Goop" to work very well in these applications!

Reattaching a new cable inside the PS; I don't know why that'd be a problem....it never has been for me before.....but I've not yet been inside a 60-series PS specifically, as JD has....so I can't advise on this point.

Richard

BTW, I got the DCPlug cable, I just need to find a dremel and cut the power supply open.

jdhurst wrote:I have taken a faulty adapter apart to see what makes it tick. The chances of properly replacing just the DC cable are probably quite slim.

And from the peanut gallery here (along with yards of experience), I do NOT recommend a cheap knock off adapater. Get the correct one for your machine for good long term reliability.

For those that care, I bought a knock off that failed after a day or so of use. Instead of immediately throwing it away, I opened up both the knock off and my original adaptor, desoldered the DC cables from both power supplies, and then soldered the DC cable from the knockoff onto my original, a straight replacement to the circuit board. It worked fine but now a few months down the track and I need another cable. I'm honestly considering just buying like 10 of them, so I can have one for when they inevitably break. I am quite hard on my power cables.

This whole problem has left an incredibly bad impression on me. I love my Thinkpad, it's the best laptop I've ever owned, but just this particular issue is forcing me to consider trying something else. If Lenovo are reading this: fix it, it's costing you customers.