770 powers up / fans but....nothing!

[solidpro]

Hi Everyone

I got my hands on a 770 in good condition. It powers up but does nothing. No beeps.... I removed everything I could - drives, hibernation battery, CMOS battery, PCMCIA cards, main battery, optical drive, hard drive.... plugged in an external monitor and nothing. Before I end up dismantling the whole thing to see if I can get any life out of it does anyone have any suggestions?

I've not had many 77x machines but they all felt really reliable...

Thanks

[SMA]

Most likely another failing DC-DC board.

[solidpro]

Hi - can you elaborate? I should be able to repair if I knew what was the common failure point.... thanks!

I guess I would need to get the multimeter and measure the rails, but where would be the easiest spot to do this? On some old macs for example you can measure on some pins of the external floppy drive port. Is there any easy ways to test the DC rails in a thinkpad?

[SMA]

Back in 2006 when I first got my 770x it came to me with symptoms that I recall as being similar to yours.
By googeling, I found someone saying that what they used to do in such cases was to replace the DC-DC board.
So I ordered a replacement DC-DC board and it worked for me.

I can see from me old notes that there were a MAX1630 chip getting hot and a broken resistor on the faulty board.

[MikalE]

Sounds like the exact same problem with my new T16, but the MB is bricked.

I don't know how available the 770 system board is, but you might want to be shopping for one of those too.

[solidpro]

Back in 2006 when I first got my 770x it came to me with symptoms that I recall as being similar to yours.
By googeling, I found someone saying that what they used to do in such cases was to replace the DC-DC board.
So I ordered a replacement DC-DC board and it worked for me.

I can see from me old notes that there were a MAX1630 chip getting hot and a broken resistor on the faulty board.

You've got quite a memory. I guess I'll take it apart and try to determine which board the DC-DC board is. I might get lucky and find someone breaking up a 770 on ebay some time...

Best Wishes

Alex

[Enig]

Hey Solidpro,

I think the DC-DC board is 24. in this part list / exploded view:
http://ps-2.kev009.com/eprmhtml/epr2d/f6052.htm
For the plain 770 - FRU: 12J0413

[kfzhu1229]

I second that the power board is screwed. My 770ED died completely (no life at all) and I am very certain the MAX chip is fried and wouldn't drive the correct voltage rails.
Unfortunately the power board is the common failure point so it makes it harder for you to get a working one when they are already quite rare.
I then got a ThinkPad 600 instead for retro needs and it's definitely a lot more reliable.

[solidpro]

I managed to find a replacement DC-DC board. Stripped the machine and swapped it and.....no change. Then I realised I had a CPU from a 600 which uses the same connectors as the 770. So I swapped it and.....nothing different.

Then I noticed that the LCD was flickering on power up which wasn't happening before. I grabbed an external LCD and..... it powers up!

I switched back to all original hardware and it's working!

So it just seems everything needed reseating.... I need to replace the LCD but we are on our way to a working 770!

The keyboard palmrest is damaged. If anyone happens to have a replacement palmrest, please let me know!

Thanks

Alex

[kfzhu1229]

So it just seems everything needed reseating.... I need to replace the LCD but we are on our way to a working 770!

The keyboard palmrest is damaged. If anyone happens to have a replacement palmrest, please let me know!

Thanks

Alex

I have both a working screen and a palmrest physically in one piece (a little sticky of course) but you are gonna need to swap some electronics as one of the ribbon cable is ripped.
Screen works fine I know for sure but I remember has a bit of stain on it or something.
If you are interested let me know
And these are for 770ED, which should work for your 770 (but not the X and Z versions with 5:4 screen)