Using The Wrong AC Adapter - Advice Please

[INTJ]

Hello, Merry Christmas and a Happy New Year,

I live in Thailand and recently bought a Thinkpad R31, second hand, private sale.

I have noticed when I power up the unit and the battery is less than 70% full and charging, the machine beeps frantically and the screen goes dimmer and brighter. This is presumably as it shifts between processor speeds. After it has been running for half an hour or so, this stops and all seems well. If the battery is 70% up, everything seems fine.

Upon further examination, it seems I have been given the wrong AC adapter with the computer. It is an original IBM part, but suited to an older model. The output of this adapter is 16 volts, 3.36 A. This machine should use 16V, 4.5 A.

Because of my location, sourcing the correct part would be difficult and expensive.

I would like to know if using the incorrect power supply is likely to cause any damage to my machine. Most of the time I use it straight from the mains with the battery removed. It seems to function with no problems. Also, charges the battery fine. I would not have noticed this at all if it were not for the beeping I described above.

Thanks in Advance,


INTJ

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[jdhurst]

Using an under-powered adapter will surely overheat the adapter, likely damage it, and possibly cause a fire. If the adapter's power rating is exceeded, the output voltage could drop, and that could damage your laptop. This is not a good thing to do. ... JD Hurst

[INTJ]

Hi,

Thanks for your prompt reply.

In your opinion, is this adapter underpowered enough to cause a serious problem ?

The voltage is the same, 16 volts. The difference is the ampage, I am using 3.36 instead of 4.5. I don't exactly know what amps mean, is it the strength of the current ?

Thanks,


INTJ

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[INTJ]

Hi,

Just found this on

www.laptop-chargers.co.uk/connect.htm

"Whatever you call them, they are expensive, troublesome, machine specific and absolutely necessary! You can run a laptop with a dead battery but not with a dead adaptor! Your laptop is worthless without one! Your laptop can be destroyed by the wrong one!"

"If it fits will it work? It might, it might not and it may destroy your laptop or the adaptor! The important factors are not just "does it fit" - adaptors vary, commonly, from about 14 volts to about 24 volts and the amperes also vary. You can usually determine the correct volts and amps from your old adaptor or from a plate adhered to the underneath of your laptop. You need the correct voltage (+ or - 1.5v) to not cause short or long term damage to your laptop or the adaptor."


BUT THEN :-


"The amperage (capacity) is not quite so important. The result of a lower amp output is that your battery will take longer to charge and if it is significantly lower you may have trouble running everything on your laptop at the same time when running from direct power, i.e. when your battery is flat or does not hold a charge. The result of a higher amp output will be a faster charge and all else should be fine"



Can anybody else cast any light on this ?


Thanks,


INTJ


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[JHEM]

You MUST match the voltage as closely as possible between the power brick and the laptop, while amperage is a bit more forgiving.

BUT, you should never rely too greatly on an under-powered adaptor to both run the unit and charge the battery while on AC. Best in this instance is to do one or the other, i.e. charge the battery while the unit isn't being used.

Yes, a low amperage adaptor can cause long term damage to the laptop's internal charging circuitry as well as the laptop's internal power supply. You should do your best to get the correct adaptor.

Regards,

James

[JimmyD]

That's about all the light there is, DON"T gamble for the sake of a few buck's. Get the correct adapter and spare yourself the worry and poss. problem's. Jimmy

[hausman]

In my experience, if the voltage is correct, a lower amperage rating simply means that battery recharge time will be longer and that you won't be able to run everything at once off AC (i.e. recharge battery, have LCD at max brightness, watch a DVD, all while doing I/O intensive work in the background.) I've used an AC adapter from a 760 to power my 770 and A21p. I even had to change the DC plug from IBM's old proprietary square design to the now standard tubular one. Never had a problem so long as I didn't "push" the adapter.

That said, I'd still look for the correct adapter and use it as the primary one.

[INTJ]

Thanks for all your replies.

I will keep my eyes open for the correct "brick", but without any urgency.


Happy New Year !


INTJ


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[djspoof]

yeah ebay that adapter and get it! i've put the wrong adapters with slightly varying volts on lots of different hardware in my time and NONE have ever worked correctly (except my linksys switch magically, but i wouldn't put money on that ever happening again). you'll notice weird unexplainable errors with wrong power supplies. sounds like you are having a weird one now since i have that exact laptop and the correct adapter and have never seen anything like you have described.

[SeanM]

Charging the machine with the power off shouldn't be a problem. But using your R31 while connected to one of those 56W adapters will cause the screen to flicker, you'll hear beeps, you may see BSODs or other crashes, and may experience data loss.

I'm with Jimmy on this, don't gamble with it. Get a 72W adapter. The longer you run your machine on the adapter you're using, the more you stress the poor thing. The more you stress it, the sooner it will die.

[djspoof]

the sooner it dies the sooner you are sad