770E as good as dead - hopefully not!

[greenbunnygirl]

Hi, I've just joined this forum - hoping for advice about how to get my TP up and running again. When I switch it on there is a slight humming sound, sounds like the fan, and the loudspeaker symbol on the left of the LCD screen flashes. There is absolutely no other sign of life. The power indicator light is not on. The battery doesn't work anymore, so I'm powering up through the mains cable. So far I've tried:
- using different power cable (both cables work with another computer)
- switching on with recovery disk in CD drive
- switching on while pressing F1
- pressing Fn f12, fn f3 and fn f4 in case it's sleeping
- pressed down on the IBM logo while switching on (saw this somewhere else on the forum)
- removed HDD, battery, and DVD player, and started without these
None of these made any difference. Last time it was used it wasn't working properly, but still worked enough to open windows. As far as I remember it's running Win 2000. It has been upgraded but I don't remember the spec now.
Hope this isn't too much information, but can anyone help?

Thanks
Sheila

[cmarti]

Does it post? Can you hear a beep? Any codes on the screen?

Try turning it on with a lcd attached it may be a video problem.

[greenbunnygirl]

There are no beeps and nothing on the screen, also no sounds that may indicate disk activity, only the quiet hum. Please would you explain turning it on with an lcd attached. I'm not sure - always been more of a computer user than fixer!

[cmarti]

The lcd won't help, if it is not posting ( the beep ) Im sure it is a planar problem ( motherboard )

[greenbunnygirl]

Thank you. I was hoping it wouldn't be that - am I right in thinking that there is nothing I can do with it now?

[rkawakami]

A belated "Welcome to thinkpads.com!"

You may want to try getting back to basics before dumping the system. Try removing all hardware (hard drive, memory, etc.) and leave just the bare shell. Power up and you should get at least some error codes and/or beeps. If you don't get any indication of life, then as cmarti indicates, it's probably the motherboard and there's usually not much you can do. If you do get any semblance of life (error message or beeps), then put back one memory module and power it up again. Continue to replace hardware until the system acts up again. If you have a second memory module, then install that one separately from the first. If you think you've isolated it to a certain piece, come back here and we'll continue from there.

For reference, here's a link to the 770 Hardware Maintenance Manual (HMM) from Lenovo:

770 HMM

It contains fairly detailed instructions on how to remove everything from the system and has lists of error codes and their meanings.

[Robbyrobot]

Try removing all hardware (hard drive, memory, etc.) and leave just the bare shell. Power up and you should get at least some error codes and/or beeps. If you don't get any indication of life, then as cmarti indicates, it's probably the motherboard and there's usually not much you can do.

You know, this is starting to puzzle me. I got a 770E from a friend with the same symptoms greenbunnygirl describes - after pushing the power switch, the fan starts, the computer starts to POST, and then everything stops except that the LCD display shows an icon of the loudspeaker. No sounds, no beeps. Push the power switch a second time and the LCD display goes off again.

I've tried everything I can think of, including what you suggest and greenbunnygirl tried, equally without any further reaction. So is this a "motherboard defect"?

If so, there must be a lot of precisely the same defect around, since I bought another 770E via Ebay in the hope that I might be able to use its parts to get my 770E running again - but instead the new 770E ALSO has PRECISELY the same problem as my original 770E and greenbunnygirl's 770E.

Now, I'm willing to believe in coincidences too, but this seems just a bit too much to me, and I'm wondering whether there isn't some kind of "typical problem" the 770Es have that causes this. And if this is so, who else has been affected and what comments they can make on the subject.

I haven't really taken either of the two affected 770Es apart to see if I can see anything obviously wrong, but plan to do that as soon as I have time. In the meanwhile, I'd be interested in any comments from the 770E community on this subject.

[greenbunnygirl]

I didn't feel confident about taking mine apart myself, so gave it to a friend of a friend to check out. I've actually forgotten what he found, for the moment, but he did say it was beyond repair. I'll find out exactly what was wrong with it.

Such a pity because it was a really lovely laptop!!

Sheila

[SMA]

Hi

The power circuitry inside the 770 machines are located on a seperat board, called a DC/DC board.
For the 770E/D the FRU number is 10L0890.
I belive that is the board causing the problems.

[pkiff]

I've tried everything I can think of, including what you suggest and greenbunnygirl tried, equally without any further reaction. So is this a "motherboard defect"?

If so, there must be a lot of precisely the same defect around [....]

Now, I'm willing to believe in coincidences too, but this seems just a bit too much to me, and I'm wondering whether there isn't some kind of "typical problem" the 770Es have that causes this. And if this is so, who else has been affected and what comments they can make on the subject.

I haven't noticed any particular pattern in problems relating to the 770E motherboards. But I would note that just because these units display identical start-up sequences does not mean that they all have the same problem. The overall problem is that none of them can complete a basic POST (Power On Self Test). The underlying reason may be that someone spilled water on the motherboard, the motherboard memory or CPU overheated/burnt out, the DC-DC power card is shot, etc. etc.

I personally have had my 770E display this startup sequence (stopping with the loudspeaker symbol and nothing else) because of a HARD DRIVE problem that could be solved simply by replacing the hard drive. But that wouldn't be the culprit if you've pulled all devices out of the unit, including the hard drive, in order to test it with nothing but the shell.

Phil.

[Robbyrobot]

I haven't noticed any particular pattern in problems relating to the 770E motherboards. But I would note that just because these units display identical start-up sequences does not mean that they all have the same problem.

Good point, and one I should have considered to begin with. So on the good side, I still have a possibility of fixing one of the two 770Es by cannibalizing the other... the downside is of course that the search for the defect is harder than if I only had to look for one possible cause.

It wouldn't have occurred to me to look at a hard disk as a possible cause for this, since I'd only expect a defective hard disk to be inaccessible _after_ the computer boots. But in any case, neither a hard disk, main battery, CMOS battery, insertable RAM (SODIMM) nor any other easily removable periphery is at fault here, as all were removed for testing.

A further possibility I hadn't immediately considered (didn't know the 770E has _three_ batteries and not just two) might be the backup battery under the keyboard, since it's surely more likely that a batter go dead than a PCB assembly or the CPU. But I don't know if a dead backup battery will cause this kind of symptoms... just have to check it to be sure.

[Later] No, that wasn't it either, at least not in the one I checked (3.95 V, well over the 3.5 the HMM specifies). Keyboard removed, LED removed, backup battery removed... and when the power is switched on (from the AC adapter) the fan starts up, then after a few seconds dies down to a soft hum again and that's that. Have to look further.

[Even later] Well, after a long day's work I have a working 770E made up of parts of the two defective ones. Everything looks fine except it seems like I have some defective memory that's not being properly recognized, but substitution of other modules shows it's only a problem with a module, not with the computer.

I have no real idea what I did right... one of the problems you have trying to put two defective computers together to get one working one is the fact that you can't test the modules - DC/DC board, Graphics board, CPU board, motherboard - to see what's good and what's defective. I assume the CPU was defective in one of the 770Es, as switching the DC/DC board alone didn't help. I only started to get beeps after I also switched the CPU board.

One thing I can say is that you become an unwilling expert taking Thinkpads apart and putting them together in the course of such work... and you develop a real _hate_ for people who design a laptop using screws of the same size but various lengths, where a longer-than-expected screw can either cause permanent damage or at least block a bay. I had to take the finished computer apart three times to correct such stuff. The HMM is useful, but what you have to do is only really clear after you've done it.