Thinkpads Forum

To the technically savy ...

i am going to buy a T60p and i already own a T42p. I also planned to buy a the Combo Power adapter in order to be able to fly and move with the PC.
In order to save some bucks i wondered if i bought the Combo for the T60 (90 watts) it would work for the T42 i already own (which theoritically need 72 watts only)?

thank you

No it will not. The connector on the t60 is different to that of the T43

Thank you!

snife wrote:The connector on the t60 is different to that of the T43

True -- but the much more important point is that the voltage expected by a T43 is different than that expected by a T60. Don't make the mistake of adding a T43 connector to a T60 power adapter and then trying to use that adapter for a T43.

EOMtp wrote:

snife wrote:The connector on the t60 is different to that of the T43

True -- but the much more important point is that the voltage expected by a T43 is different than that expected by a T60. Don't make the mistake of adding a T43 connector to a T60 power adapter and then trying to use that adapter for a T43.

What would be the expected voltage - 20V ?

More than the voltage, i beleive it is the watts involved that he is talking about here.
T42/43 are using 72W when T60 use 90W. Voltage is the same in both case.

astpaul wrote:More than the voltage, i beleive it is the watts involved that he is talking about here.
T42/43 are using 72W when T60 use 90W. Voltage is the same in both case.

My point exactly - voltage is the same. 90W (T60) can be used for both, more powerfull power supply will not cause any damage to T42.

It wouldn't cause damage, but the problem is that it wouldn't fit the adapter port. The port on the older T4 machines is much smaller than the new T6 models.

MG.

MobileGuru wrote:It wouldn't cause damage, but the problem is that it wouldn't fit the adapter port. The port on the older T4 machines is much smaller than the new T6 models.

MG.

Few posts up someone suggested adapter T42/T60....in which case both T42 or T60 can be used with 90W PSU.

Mirage wrote:

astpaul wrote:More than the voltage, i beleive it is the watts involved that he is talking about here.
T42/43 are using 72W when T60 use 90W. Voltage is the same in both case.

My point exactly - voltage is the same. 90W (T60) can be used for both, more powerfull power supply will not cause any damage to T42.

NO. There seems to be mass confusion here -- the 4 posts immediately above this one are wrong. The T60 uses a 20v adapter; the T4x uses a 16v adapter. Forget the wattage; it is NOT the concern. If one feeds 20Vdc into a Thinkpad expecting/rated for 16Vdc, then one is likely to "fry" components inside the Thinkpad.
Watts don't fry; voltage does (at least for the purposes of this discussion).

Some T60s (depending on the configuration) may run with a 72W adapter, just like most T4x do. But, just as on the T4x, the battery may not charge properly. Also, some of the higher end configurations of the T60/T60p really require a lot more power.
In any case, as someone else pointed, that is not the point. The T60 uses 20V, the T4x (along most of the older T an X for that matter) uses 16V. The T60 might work with 16V -- after all my T42 did work on 14V, because it has built-in regulation and voltage boosting circuitry. But do you really want to take the risk to experiment? It's just not worth the savings. And it might void your warranty.

EOMtp wrote:

Mirage wrote: My point exactly - voltage is the same. 90W (T60) can be used for both, more powerfull power supply will not cause any damage to T42.

NO. There seems to be mass confusion here -- the 4 posts immediately above this one are wrong. The T60 uses a 20v adapter; the T4x uses a 16v adapter. Forget the wattage; it is NOT the concern. If one feeds 20Vdc into a Thinkpad expecting/rated for 16Vdc, then one is likely to "fry" components inside the Thinkpad.
Watts don't fry; voltage does (at least for the purposes of this discussion).

I stand corrected, I took for granted that previous posts about 20V were correct, indeed, T4X series runs on 16 V.

Saying all that and knowing exactly what I'm talking about - having 20V instead of 16V wont do ANY damage to T4x series.

Nothing will "fry" inside due to few volts more - voltage coming out of 20V AC adapter fluctuates from 18 to 22 volts (depending of the mains voltage and the load). Voltage regulators are in the laptop itself, running in switching mode (to reduce heat) and they should tolerate (at least) up to 28VDC (standard spec) on the jack.

In terms of warranty - unless you connect something like 50VDC and explode input capacitors there's no way for anyone to say for sure what killed switching circuitry. In fact, those mosfets can be replaced on desktop pc motherboards without major drama.

Mirage wrote: In terms of warranty - unless you connect something like 50VDC and explode input capacitors there's no way for anyone to say for sure what killed switching circuitry. In fact, those mosfets can be replaced on desktop pc motherboards without major drama.

Oh....I don't know about that; given some good looking into it, it wouldn't be that hard to come up with what killed it. Yet something like that is more akin to foresnics and actually costs a good deal more money for nothing much in terms of what is gained, at least from a warranty standpoint. Is somebody going to pour more money into something that, either way, got fried and won't come back save for a board replacement? Probably not.

christopher_wolf wrote:

Mirage wrote: In terms of warranty - unless you connect something like 50VDC and explode input capacitors there's no way for anyone to say for sure what killed switching circuitry. In fact, those mosfets can be replaced on desktop pc motherboards without major drama.

Oh....I don't know about that; given some good looking into it, it wouldn't be that hard to come up with what killed it. Yet something like that is more akin to foresnics and actually costs a good deal more money for nothing much in terms of what is gained, at least from a warranty standpoint. Is somebody going to pour more money into something that, either way, got fried and won't come back save for a board replacement? Probably not.

It is THAT hard actually. Same damage can be caused by high voltage spike generated by lightingstrike or even arc welding machine connected to nearby mains socket. However, 20V instead of 16V will NOT cause any failure whatsoever.

Mirage wrote:Nothing will "fry" inside due to few volts more - voltage coming out of 20V AC adapter fluctuates from 18 to 22 volts (depending of the mains voltage and the load). Voltage regulators are in the laptop itself, running in switching mode (to reduce heat) and they should tolerate (at least) up to 28VDC (standard spec) on the jack.

Mirage, Please tell me: Do you know this for a fact or is it what you think ought to be the case? I.e., have you examined T4x motherboards and verified it? I understand the theory and I would expect precisely as you state ... still, I would like to know if you have examined the circuitry in the Thinkpads and if you have verified that it is indeed designed to handle the margins in question.