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IBM Thinkpad 770 - Wont boot without PSU

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jamiecruickshank
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IBM Thinkpad 770 - Wont boot without PSU

#1 Post by jamiecruickshank » Thu May 10, 2018 10:59 am

Hi All,

I am new to the forums and have had a good search but cannot find my exact issue.
I have an IBM ThinkPad 770 in amazing condition. I received it with a dead battery and have replaced the battery.
The Laptop will boot, charge and run of the battery however if I shutdown or power off the Laptop it wont power back on until I plug in the power supply.
If I remove the power supply immediately after it will continue to work for well over an hour.

Has anyone else seen this type of issue?

Thanks for your help.

Jamie

madicetea
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Re: IBM Thinkpad 770 - Wont boot without PSU

#2 Post by madicetea » Thu May 10, 2018 3:43 pm

jamiecruickshank wrote:
Thu May 10, 2018 10:59 am
Hi All,

I am new to the forums and have had a good search but cannot find my exact issue.
I have an IBM ThinkPad 770 in amazing condition. I received it with a dead battery and have replaced the battery.
The Laptop will boot, charge and run of the battery however if I shutdown or power off the Laptop it wont power back on until I plug in the power supply.
If I remove the power supply immediately after it will continue to work for well over an hour.

Has anyone else seen this type of issue?

Thanks for your help.

Jamie
In this specific case, I have not heard of such a problem ever before. I think maybe you should check to make sure that the cells in your new battery hold enough capacitance [not the amount of juice, as the flow rate of it, per se] that they can start a machine (which requires an amount 'x' more power than the sustained amount to keep an already-on machine running).

I envy your battery pack, do you re-cell your own or did you find a rare top-grade battery out there?
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Re: IBM Thinkpad 770 - Wont boot without PSU

#3 Post by jamiecruickshank » Thu May 10, 2018 3:46 pm

Thank you for the reply,

I have tried 2 batteries in the machine. The battery that was purchased gives me just over an hour of use.
I have also replaces the cells in the original battery and again, it charges and runs fine but wont power up the machine.

I think there must be an issue with the DC board on the laptop as it has done it with two batteries.

Thanks
Jamie

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Re: IBM Thinkpad 770 - Wont boot without PSU

#4 Post by madicetea » Thu May 10, 2018 3:52 pm

jamiecruickshank wrote:
Thu May 10, 2018 3:46 pm
Thank you for the reply,

I have tried 2 batteries in the machine. The battery that was purchased gives me just over an hour of use.
I have also replaces the cells in the original battery and again, it charges and runs fine but wont power up the machine.

I think there must be an issue with the DC board on the laptop as it has done it with two batteries.

Thanks
Jamie
Yes, if it is not the battery it can always be in the hardware as well - I'd check the DC power supply plug-in cable to the planar and, last resort, the planar itself.

If you have a multi-meter handy, it shouldn't be a hard check.

Hopefully, you find a solution.
Greetings from Tokyo,
MadIceTea
, IBM Thinkpad Enthusiast

Daily Driver Thinkpads: X250 16gb, X61 T9300 SXGA+
Under Construction: PC110
Occasional Use: x2001 AFFS i5-530 (in my lab) , piano black s30
For Sale: X250 WXGA LCD w/ Lid; some batteries

jamiecruickshank
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Location: Fife, UK

Re: IBM Thinkpad 770 - Wont boot without PSU

#5 Post by jamiecruickshank » Thu May 10, 2018 3:54 pm

I have checked as much as I can on the DC board, however I couldn't find any schematics. The voltage does get to the board from the battery but without the Schematic, I am not 100% sure where to look.
I have repaired Laptop Boards before on component level but I have always had the schematics.

Thanks
Jamie

madicetea
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Re: IBM Thinkpad 770 - Wont boot without PSU

#6 Post by madicetea » Thu May 10, 2018 4:12 pm

Ah. Unfortunately, I do not have the schematics either.

Hopefully someone more knowledgeable can assist with your case.
Greetings from Tokyo,
MadIceTea
, IBM Thinkpad Enthusiast

Daily Driver Thinkpads: X250 16gb, X61 T9300 SXGA+
Under Construction: PC110
Occasional Use: x2001 AFFS i5-530 (in my lab) , piano black s30
For Sale: X250 WXGA LCD w/ Lid; some batteries

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Re: IBM Thinkpad 770 - Wont boot without PSU

#7 Post by RealBlackStuff » Thu May 10, 2018 4:18 pm

Lovely day for a Guinness! (The Real Black Stuff)

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Re: IBM Thinkpad 770 - Wont boot without PSU

#8 Post by kfzhu1229 » Thu May 10, 2018 9:50 pm

My suspect is probably that one of the capacitors are done for.
See if you can measure any faults with voltmeter over the capacitors
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Re: IBM Thinkpad 770 - Wont boot without PSU

#9 Post by axur-delmeria » Thu May 10, 2018 11:24 pm

kfzhu1229 wrote:
Thu May 10, 2018 9:50 pm
My suspect is probably that one of the capacitors are done for.
See if you can measure any faults with voltmeter over the capacitors
For electronics this old, I'm inclined to agree.
It would help if you have an oscilloscope and a copy of the schematics.
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Re: IBM Thinkpad 770 - Wont boot without PSU

#10 Post by jamiecruickshank » Fri May 11, 2018 3:08 am

I did think it was the capacitors too, I have ordered a replacement set, there is only 2 through hole electrolytic capacitors and one surface mount.
I do have an Oscilloscope but I am in the process of moving house next week and its packed away at the moment.
They visually look okay however, I will replace them anyway. I managed to obtain a new DC / DC board for the machine and its on its way, I will let you know the outcome.

Oh and just a note, I tested the battery I purchased and got over 2 hours, I just bought it from eBay recently, which I thought was amazing for an old used battery!

Thanks for your replies,
Jamie

kfzhu1229 wrote:
Thu May 10, 2018 9:50 pm
My suspect is probably that one of the capacitors are done for.
See if you can measure any faults with voltmeter over the capacitors

jamiecruickshank
Posts: 5
Joined: Thu May 10, 2018 10:56 am
Location: Fife, UK

Re: IBM Thinkpad 770 - Wont boot without PSU

#11 Post by jamiecruickshank » Mon May 14, 2018 12:59 pm

I wanted to give everyone an update, I have bought a replacement DC/DC board and the fault still persists. I presume its going to be a motherboard fault as I have replaced every other component.
I was wondering, I seem to have a wire running on the motherboard under the RAM cover, its very professionally done and was wondering if anyone else has this? It looks like it was done from the factory.

Thanks
Jamie

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Re: IBM Thinkpad 770 - Wont boot without PSU

#12 Post by kfzhu1229 » Mon May 14, 2018 2:09 pm

forgot to mention, check all the fuses.
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Re: IBM Thinkpad 770 - Wont boot without PSU

#13 Post by Rickeyboard » Tue Jul 17, 2018 8:07 am

I had some issues like this, Id have to do the battery/button/AC trick to boot, I couldn't just do the battery/button...., Id still have to plug-in the AC/PSU to boot, then I could remove the AC, and it would work fine, but I couldn't power down with on/off button. Here's a link to what I found. Notice that I mention ware marks exposing traces on keyboard ribbon cable, I believe this to be the cause,,,, from vibration of HHD, Etc, and cable rubbing chassis over time. I should have taken pics.


viewtopic.php?f=48&t=126616

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