Thinkpads Forum

Hello,
I took a chance today at goodwill computers and bought a T61 that they said would not power on and had labeled "as is" . It looks great and has all of the necessary components. I have spent a lot of time fixing T4x laptops but I have never opened a T6x before. I wanted some advice on what I should try out before I just go ahead and replace the mother board. Thanks for your help!

To begin:

- pull out all parts that plug into the system; memory, hard drive, MiniPCI, CDC, Ultrabay, etc.
- using a known good battery (no AC) see if it powers up and issues the missing/bad memory beep code (1-3-3-1)
- if no response at all (no LEDs lit, fan spin, beeps), try a known good AC adapter (remove the battery)
- if that doesn't work, then the problem could be as simple as a blown fuse on the motherboard or something more drastic

- assuming that the system powers up with either the battery, AC or both, then re-install the memory (or use a known good module) and see what happens
- assuming that the system boots with some memory installed, re-attach ONE component at a time and power back up (I'd start with the internal communication cards first)
- if the system goes dead again, the last part you re-installed has a problem

all right I have tried all of the things above, so I know I am dealing with an issue on the mobo here. How do I tell if it is a blown fuse? What parts of the mobo should I check before I replace the entire thing?
Thanks.

Fuses can be checked by using an ohmmeter (aka, multimeter). Place the meter in the lowest OHMS range, connect the leads across the fuse and if it reads 0 ohms, the fuse is good. (NOTE: remove all power from the system before doing this!) The problem is identifying which components on the motherboard are fuses. If you look closely, you will see part names written in white ink (generally) on the circuit board. Fuses will usually begin with "F" (i.e., F1, F5, F11, etc.). A picture of some fuses from a T22 is here:

http://www.kawakami-ca.com/images/t22_main_fuses.jpg

The T61 will use similar looking fuses. That said, your problem may be more serious than a fuse. If the system does not operate with either a known good AC adapter or a battery, then that means two separate fuses would have to be defective. There's one that protects the DC input jack and another one that protects the battery. This usually means that there's some other power problem on the motherboard. If that's the case, look closely at all of the components to see if you can detect any catastrophic failures like the one circled in this photo:

http://www.kawakami-ca.com/ibm_t2x/let.jpg

The other components outlined in blue are also fuses. You should also look for any parts that may have come loose from the board. This could entail removing the entire motherboard as there's also parts soldered on the back side.

Thank you very much. Both of your posts have been helpful and thorough, I appreciate your time. I'm going to examine the board here soon.