T20 2647-46U power up problem

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PSUser · #1 Post by **PSUser** » Sat Apr 08, 2006 2:55 am

First, I want to say THANX for this support community.

My laptop will only complete boot up to Win2000pro if the AC adapter is unplugged (with a charged battery) OR the battery is removed (with the AC plugged). Once fully loaded, I can attach the AC or put the battery in and works great. Today, I loaded the Intel Speedstep dwnld from IBM only to make matters worse (it would freeze up after plugging in or installing the battery). I've got several batteries, all genuine IBM, tested in other units. I've tried different AC adapters as well (4.5A & 3.36A) with the same results. I've tried a port replicator too, in an attempt to avoid using the AC jack on the rear of the unit.
To consider: This unit should be running at 700MHz, but states 548-550MHz under system information, SanSoft SISandra and Intel Processor Frequency/ID utility, even with everything plugged in and setting on High Performance (the laptop responds by brightening the TFT, etc.) This is one of my headaches. Bios version is IYET60WW (1.21), not IYET61WW (1.22).
Note: I immediately uninstalled the Intel Speedstep software so that I could again plug in after unit boots and loads.

Website · #2 Post by **tfflivemb2** » Sat Apr 08, 2006 8:28 am

Not sure about the power problems, but as for the CPU problem, it reads less than the 700MHz because it has Speed Step. Your system will still run at 700 when it is needed, but until then it will register about 150MHz less. I believe that there is a feature in the BIOS that allows you to set it to full power at all times. This is meant to be a power saving feature, especially for battery conservation.

PSUser · #3 Post by **PSUser** » Fri Apr 28, 2006 4:27 pm

recently swapped out backup battery with another T20; still same power on problem.

I fully understand the stepping-down of processor speed; I don't know if anyone else has similar problems with this model.

ArtJ · #4 Post by **ArtJ** » Thu Nov 23, 2006 9:03 am

Hi.....I also experience the exact same problem on my T21 when booting into Win2K pro. I've only ever run Win2000 on this machine so I don't know if it's a problem with other OS's. I've updated the BIOS, all drivers, re-loaded the OS, swapped processors, batteries, AC adapters and fans to no avail (the current MB is an Ebay replacement for the original MB which died an untimely death).
It seems that the problem abates when the battery is fairly well discharged...i.e. when the battery is below 50% charge and the PC is plugged into the AC adapter the machine will boot normally. That tells me there must be some kind of over-voltage check being performed during POST which is failing under high battery charge. The cause is elusive to say the least!

Thanks to Bill for providing my membership privileges!

PSUser · #5 Post by **PSUser** » Thu Nov 23, 2006 11:32 am

Art - it must just be a New Jersey problem

ArtJ · #6 Post by **ArtJ** » Thu Nov 23, 2006 9:24 pm

Ha......good one....add that to our list of problems! When I decide to move out of state I'm leaving the T21 on the curb for the next sucker!

Website · #7 Post by **tfflivemb2** » Thu Nov 23, 2006 11:03 pm

Well, I'd be more than happy to take it off your hands.

ArtJ · #8 Post by **ArtJ** » Fri Nov 24, 2006 7:45 am

I'll let you know how it goes! Right now the T21 is my shop computer so it really doesn't have to do any heavy lifting for me. Funny thing is no matter how much grief it gives me I haven't been able to part with it....I must be a Thinkpad devotee.

ArtJ · #9 Post by **ArtJ** » Sun Nov 26, 2006 11:19 am

Just as an FYI....my final attempt to fix this power-on problem failed......I flashed the latest version of the Intel Boot-Agent from the IBM site...waste of time.

vlyne · #10 Post by **vlyne** » Mon Nov 27, 2006 12:34 am

Another T20/1 bites the dust! Add this to the list of voodoo tricks to get these machines going:

Take off all devices/cards and main battery (and A/C power).
Add minimal memory.
Drain remnant charge by pressing power-on button for a few times.
Hold power-on button down
Insert A/C power (whilst still holding down poweron button)

If the machine doesn't fire up. Leave it a corner for a day or so and try again.

I just added another one to the corner a couple of days ago. I'm running out of corners...
Cheers

ArtJ · #11 Post by **ArtJ** » Tue Nov 28, 2006 9:01 pm

Hi......the power problem described in this thread is a bit different from the typical T21 failure. The machine will power on every time as long as the AC adapter is not plugged in during boot-up! Go figure!

vlyne · #12 Post by **vlyne** » Tue Nov 28, 2006 9:35 pm

OK, I've re-read the post. Got it! The original post did indicate that the machine would work with A/C alone but in your case that doesn't work unless battery is half dead/alive. If the problem is repeatable then yes I'd agree that it's different from the typical T20/21 failure. Whatever device it is that is failing either controls or shunts a lot of current from A/C and/or battery with a fair amount of heat sinking. I'll have anther look at my disassembled T21 later on when I get home.
Cheers

ArtJ · #13 Post by **ArtJ** » Thu Jan 25, 2007 1:36 pm

I haven't given up on this problem completely...yet. Now I wonder if there's an IRQ conflict with the power and audio drivers...I may try the latest Lenovo audio driver dwonload and see what happens but I'm not holding my breath!

losmeme · #14 Post by **losmeme** » Thu Jan 25, 2007 3:27 pm

I've the exact model os the OP, with the exception that I am running it with a T30 battery. I use the heck out of this machine and have never had a problem. I alomst always use it on Ac as well.

Do you think the original T20 battery could have something to do with the power on problems?

ArtJ · #15 Post by **ArtJ** » Thu Jan 25, 2007 3:41 pm

I don't think the battery is causing the problem. I swapped it out for a new T23 battery and experienced the same problem. There seems to be either a MOBO-related problem during POST or some other kind of conflict. It's not a show stopper but it's a bit annoying.....the cure is to just put the machine on standby when not in use with the ac power adapter unplugged....when the battery has drained that's the time to plug back in.

T20 2647-46U power up problem

T20 2647-46U power up problem

problem remains

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