encrypted X61s, curious failure sequence

[precip9]

This is an X61s with 8GB RAM, Bitlocker encryption/security chip, running W8.1 encrypted for several months, but with very little use. It had plenty of prior use as an unencrypted machine.
The drive is a rotating Seagate ST750XT.

Edit: There is nothing wrong with the laptop except the status lights, which are nonfunctional, except the Bluetooth light. The rest was operator error.

Update: Disassembled laptop. All parts tight. Removed/replugged LCD connector. Removed LCD bezel. Loosened/tightened inverter screws that seem to be part of the ground strap. Unplugged/plugged inverter cable. Repowered. Still have only Bluetooth light.

I guess the laptop has decided to modernize itself. Oddly, a forum search does not show anybody who actually solved this problem. It could be:
1. Cable
2. Fuse
3. Transient damage. It looks like everything on the inverter board may share a common ground through the screw on the left hand side of the inverter. A brief interruption, caused by corrosion, could cause a ground lift.

If anybody actually solved this on any Thinkpad of similar vintage, please post.

[rkawakami]

My vote would be for #2; a fuse. Check F3. Remove keyboard and look around the LCD connector.

[precip9]

Thanks.
Checked F2,F3,F4,F5, all good.

[rkawakami]

Hmmm, okay. Second choice: inverter board. And third choice: cable. Seems you've re-sat all of the pertinent connectors so it's probably not a loose connection.

Replacing each with a known good unit would be my next move if this was my machine. If those don't solve the problem, then about the only thing to try next would be a different motherboard. That's where the cost/benefit ratio rears its head; i.e., is it worth spending that much $$$ to fix a somewhat trivial problem. Lack of indicators for battery/AC power and standby state are more important than say, whether the caps or num lock is on.

[precip9]

"Lack of indicators for battery/AC power and standby state are more important than say, whether the caps or num lock is on."

That's right, and they are out. What surprises me is that in all these years, nobody has posted a case history including a fix.

Your choice of inverter over cable is logical, because if it were the cable, why would they all (except Bluetooth) be out at once?

But if inverter, why would the Bluetooth indicator still work? Recently noted, it appears the wifi indicator occasionally lights, but not in a pattern I recognize. As I write this, it reminds me almost of broken motherboard logic.

I think I'll just grit my teeth and use the thing. I have three X61s's, which I take to NY as disposable, yet rugged machines. One of the others has a history of rare freezes, which, not destroying data, seem tolerable. A complete motherboard/RAM swap did not fix this, indicating the danger of relying on eBay components.

[rkawakami]

Well, if you have other X61s systems that work properly, then you have a choice: 1) take the suspect inverter and plug it into another system or 2), grab one of the fully working inverters and put it into your problem system. If the lack of LED indicators moves with the "bad" inverter or the indicators start working with a "good" inverter, you've proved that the inverter is the problem. On the other hand, if the "good" inverter misbehaves in the problem X61s and the "bad" inverter works fine elsewhere, then that seems to point to the cable or motherboard.

There's an outside chance that whatever is wrong with the non-functioning inverter (or motherboard) could cause permanent damage to the "good" motherboard (or inverter), causing you to end up with two systems that have this problem. That's the chance you will have to take. Even with buying an inverter off of eBay, you'll first have to prove to yourself that it works by installing it into one of your fully working X61s systems. In any case, I see two partial system teardowns in your future .

Also, your "rare freeze" X61s could be due to a bad hard drive. If you swapped the motherboard and RAM but were still using the same HD, then that's one other potential source of the problem.

[precip9]

Ray,
The procedures you describe are orthodox and correct. I limit disassembly because I lack the consumables used in professional repair. The act of working on a machine, at least when I do, damages it a little bit.

As far as the outside chance, yes, but I score it lower than the damage caused by working on it.

The "rare freeze" is interesting, because EVERY SINGLE PART on that machine has been swapped, except for the lid/LCD and keyboard. So it is not the hard drive. The most likely cause is that the salvager sold me another defective motherboard.

Now here's a question. The 20V from the power brick passes through at least one DC-DC converter. It occurs to me that, since several of the LEDs are intended to be operational when the laptop is in an off state, there may be a secondary converter, part of the standby circuit, that is not as well protected as the primary. That could have resulted in blowing the LED drivers due to a power surge when plugging or hotswapping. Where are the LED drivers are located? Motherboard or inverter board?

[rkawakami]

You have a PM .