A31 will not boot, most likely bad component?

[harvester]

When I hit the power button, I get normal POST for a couple of seconds then video disappears with no hint of error messages. While still powered, an EXTREMELY faint illumination of the Thinkpad logo is barely perceptible, and can be distinguished from screen artifacts because it gets fainter when powered off.

Removed:
Hard, CD, floppy drives, battery and RAM.
Performed the "depress power button 10 times, then hold the 11th time for over thirty seconds" drill many times. Installed single "other" known good SODIMM for some of those tests.

Also, I have a good A31P chassis (works with external monitor and keyboard) with no display, no drives, and a trashed keyboard. Can I just strip the A31 and fix the A31P with little fuss? If not, please suggest cheap ways to go.

Thanks in advance!

[Harryc]

If you hook an external LCD or monitor to the A31, do you see a video display? What is the machine type and model of the A31 and the A31P? (See the sticker on the bottom of each machine..e.g 2642-3CU)

[harvester]

No joy on external display (video drops before it can cycle the monitor).

A31 is a Type 2652-C4U, Serial 78-GNYW8, build date 08/02.

Will dig out A31P carcass tomorrow to get numbers.

[Harryc]

Product: ThinkPad A31 2652-C4U
Original description: P4-M 1.6GHz (512KB), 256MB RAM, 30.0GB HDD, 15.0 XGA(1024x768) TFT LCD, 8x4x24x CDRW, Modem(CDC), Ethernet(CDC), TV out, Li-Ion battery, Win2000

(video drops before it can cycle the monitor).

I thought you said you could see a faint IBM logo at all times? If yes, video is not dropping. With the external connected, try cycling through the FN-F7 key combination a few times.

[harvester]

"I thought you said you could see a faint IBM logo at all times? "

Yes, but the display is at (full) brightness for a couple of seconds before dropping to a level that wouldn't even be visible except at very close range. CRT monitor won't cycle the internal relay one normally hears when signal triggers power up.
Will try function key cycling this evening.

Thanks for the suggestions!

[harvester]

My apologies for not rapidly replying, but the flu (unknown version) kicked my posterior.
(Get your flu shots, it's horrid and can last for weeks.)

A31P stats:

Type 2653-A5U S/N 99-GDBT7 , build date 03/06

Function key cycling on the A31 changes nothing.

Additional question:

A31P has misc bent/damaged metal covers, etc (it was an organ donor before I got it).
I AssUme I can install the board in the A31 case. If so are there any notable "gotchas" to avoid when doing that?

Thanks for the help.

[Harryc]

Are you certain the donor machine model is not 2652-A5U ? Either way, a board swap would not be an issue as long as there is no secure chip involved.

Product: ThinkPad A31 2652-A5U [change]
Operating system: All [change]

Original description: P4-M 1.4GHz (512KB), 128MB RAM, 20.0GB HDD, 14.1 XGA(1024x768) TFT LCD, 24x-10x CD-ROM, Modem(MPCI), 802.11b wireless (MPCI), Ethernet(CDC), TV out, Li-Ion battery, WinXP Pro

[90base]

My R52 was just doing the same thing, it was also freezing when ever you could get it to start up, try removing the wireless card if you have one, that is what did it for me.

[harvester]

Donor is A31P
Type 2653-A5U S/N 99-GDBT7 , build date 03/06

System board was an easy pull from the donor. ( I'm seeing why folks like working on these. )
I'll bench test the donor board again now that it's free of the case (ran fine before).

All that's left is the question if I can use the display from the A31 with the A31P system board.

Product: ThinkPad A31 2652-C4U

Will I risk destroying anything if I just plug in the A31 display to the A31P system board to test?

EDIT:
One more question:
Do I need to reinstall the security chip that came with it in the A31P system board? I don't want any security features on my machines.

[Harryc]

The LCD will work fine as long as you swap the entire assembly(cables, inverter), and you must use the same security chip or the board will boot with an error.

[harvester]

Thank you, Harryc!

Installed A31P system board into base, powered up with no accessories.
Doesn't put out enough signal to turn on my old Dell CRT monitor either, so I'll use an LCD external monitor for future testing.

The video dropout duplicated with the A31 LCD, so I dug out the supposed bad A31P LCD from my parts stash (my A31 was built from two junkers by a friend a few years back). Surprise! The LCD works, (aside from being a bit washed out in the upper left corner), so I'll guess bad inverter on the original?

I got a " 0175:Bad CRC1, stop POST task" with the A31P system board, so I reinstalled the A31 board with the 2.0 GHZ processor off the A31P.

This is well worth it for the education. A31s are certainly good for troubleshooting by "swaptronics".

Thanks for all the helpful posts. All went well, 2 GHZ proc is an improvement, and my previous 2GB Crucial and hard disk upgrades didn't go to waste in a dead machine.