[ltp] Alternative power supply for A31

[Kelvin KAN]

Thinkpad power supply connectors are univeral (at least in the IBM era). 

You may consider getting the p/s of X31.  It's 3.5Amp, but still small 
in size and weight. The highest Power-to-Weight ratio for TP I've seen. 

I am using it for T42 fine (without CD drive and the battery being taken 
out), eventho the original p/s for T42 is 4.5A.

cheers,
-
kelvin.

Richard Neill wrote:

>
>
> Mendel Cooper wrote:
>
>> The power supply for my A31 TP is starting to get a little flaky 
>> (probably
>> bad contact on ground shield litz). So, I thought I'd try using a 770 TP
>> brick. Same connector and same 16-volt output voltage. Only difference
>> is that it has a lower power rating 3.36 amps, as opposed to 4.5 for
>> the original supply. That's 53.75 watts, instead of 72 watts. Seems
>> to me that even with 20 watts less, the A31 should still be within
>> the safety margin, especially if I don't have the battery installed,
>> so battery charging will not pull extra power from the AC supply.
>>
>> When the machine is running from battery, it pulls something like
>> 22 watts.  Even when you consider that the display is dimmed and the
>> CPU running slower under battery power, I would think that with full
>> display brightness and full CPU speed the machine should still consume
>> less than 40 watts. Plenty of safety margin on a 53+ watt supply.
>>
>> Yeah, I could buy a standard 72-watt supply on eBay for about $20,
>> including shipping. And yeah, some eBay sellers warn against using a
>> 54-watt supply because of possible damage to the computer, but I think
>> they're exaggerating in order to sell their stuff.
>>
>> Anyhow, I've been running this A31 on the 54-watt supply for a few hours
>> now, and with no problems. Any thoughts or experiences?
>>
>
>
> I think you're fine. But without the battery, you lose any sort of 
> UPS. Also, when the machine is under full load, the current can be 
> higher. What about USB-powered peripherals? (Can draw 2.5W per port). 
> When running the optical drive?  I'd be surprised if you can do any 
> serious harm (except premature PSU wear and tear), but do keep an eye 
> on the temperature of your PSU, especially if you run the laptop 
> flat-out on a hot day.
>
> Richard