Indicator lights, but no backlight or Thinklight

[gaphic2]

Did I get scammed?

I bought a used 42T0153 system board to replace my old one after getting a long beep, two short beeps error. It seems to partly work, if I shine a light on my panel I see a picture. But no backlight and no Thinklight. Indicator lights do work.

From what I've read this is probably a blown fuse. Unrepairable for me, unfortunately. Are there other faults I could check for?

[rkawakami]

Seeing a "ghost" image on the display means that the video signal is getting to the panel but the backlight is not turning on. That could mean several things:

- backlight (CCFL) is blown; you basically have to replace the panel with a known good unit to determine this
- inverter board is not functional; bad inverter board, blown fuse on motherboard, LCD cable not plugged in, LCD cable is damaged, stuck lid switch sensor
- inverter is good but power to the board is not present; blown fuse on motherboard, LCD cable not plugged in, LCD cable is damaged

Non-functional Thinklight:

- actual LED is blown; you basically have to replace the LCD cable as it's soldered directly on to the flex cable
- power not getting to the LED; blown fuse on motherboard, LCD cable not plugged in, LCD cable is damaged

In my book, the first thing to do is confirm that the fuse is okay. There's no sense in spending time/money replacing other components if the fuse is dead. If you can get your hands on a multimeter, you can check the fuse on the motherboard yourself. I believe that there's a fuse map for the T6x system around here somewhere. I'll look for it in a minute. If it turns out that the fuse is blown, then I would not try plugging in you lid assembly into another motherboard as there's a high probability that you'll blow that board as well.

The other thing to do is to confirm that the LCD cable is properly connected to the motherboard. If that looks okay, then inspect the entire length of the flex cable to see if there are any cracks or tears. The cable (besides the motherboard) is the only thing common to both these faults. If the fuse is good, then a swap out of the cable with a known good unit would be the next step.

I should mention that the beep code you quoted is for a motherboard and/or LCD assembly error. It's possible that your replacement motherboard was fully functional and that whatever fault exists in the LCD assembly (basically the LCD cable and everything else in the lid) blew out the fuse.

Here's a related thread: http://forum.thinkpads.com/viewtopic.php?f=29&t=87373

[gaphic2]

Thanks for your detailed reply. You've given me a lot to consider, including the fact that I could have blown a perfectly good board . I'll check the fuses and report back. FWIW, the seller maintains the laptop was in good working order when he took it apart.

I got the beeps rebooting after a freeze crash, after picking up and moving the machine while it was on. It had frozen and crashed one or two times in the past few months exactly in the same situation, so I perhaps too hastily assumed the system board was failing slowly and gracefully.

I did swap the LCD-panel with a spare after getting the beeps, but no luck, they were still there. I did not swap the flex LCD cable, because I don't have a spare and I can't jeopardize my backup T60p.

Edit: I checked the F7 fuse (LCD inverter (CCFL power)) and the smaller one also near the LCD connector (unlabeled F? 8? LCD inverter (Inverter power)) on my old board wih the long and short beeps and they are ok. I also checked F3

I'm not sure the F3, F7, F8 series of fuses documented in the T61 are the same on the T60p. I'll check the fuses on the new board also, once I get some more work done first.

I have a spare T60p WSXGA+, but I don't think the LCD ribbons are the same as in the non-widescreen?

[gaphic2]

To recap:

Original board: based on the machine's behaviour I assumed the freeze crash and the beeps indicated a system board/gpu failure. The board's LCD related fuses seems ok.
Replacement board; works, but no backlight or Thinklight. I have not yet checked the fuses.

1. Is it possible to power up a T6x board without the lcd attached? Or will this in itself trigger the long beep two short beeps error code?
2. Can I safely use a widescreen 1680x1050 T60p ribbon, panel and inverter to test a 4:3 board? Can the unfamiliar but working lid damage the board? If the board has a fault, can it damage the working widescreen lid?

[ajkula66]

Is it possible to power up a T6x board without the lcd attached?

Yes.

Can I safely use a widescreen 1680x1050 T60p ribbon, panel and inverter to test a 4:3 board?

Yes.

Can the unfamiliar but working lid damage the board? If the board has a fault, can it damage the working widescreen lid?

No and no.

[gaphic2]

Many thanks, ajkula, for those short and sweet answers, you should be training politicians .

The new board IS good. The LCD's backlight and the thinklight work. Phew. All I have to figure out now is what is malfunctioning in the old lid. Am I right in thinking it can only be a faulty panel, inverter or flex cable? If it was a bad panel, the thinklight would still come on, right? Or am I jumping to conclusions?

[rkawakami]

If the problem with the old lid is still no backlight and no ThinkLight, then I'd suspect the LCD ribbon cable as that is common to both. A bad CCFL in the LCD panel should not affect the ThinkLight, nor would a bad inverter.

[gaphic2]

I have ordered a new ribbon cable from my local IBM Parts, I should have it in a few days. Can I again express my thanks, it's great to have such a supporting and knowledgeable community here.

[mbarker]

Please pardon my semi-hijack. I figure since you all are already talking display problems I'd jump in here instead of starting a new thread.

Anyway, my beloved T60p's display has just "died." External display works fine. ThinkLight works fine. Ghost image is visible with a flashlight. The problem began yesterday with the display abruptly quitting while in use, but it would return after the machine was put to sleep & woken up again. Now it won't come on at all.

Does this sound like bad CCFL, bad inverter board or other?

Thanks.

[ajkula66]

Does this sound like bad CCFL, bad inverter board or other?

Most likely a bad CCFL.

Has the screen been reddish/pinkish on initial boot lately?

[mbarker]

Has the screen been reddish/pinkish on initial boot lately?

No, I don't think so. But I rarely re-boot it.

The display is back to working again for just a few seconds when I wake the machine up. Then it goes black.

[wileE]

Dimm down to the lowest brightness, and see if it stays on longer.
Old or defective CCFL at some point need more power than the inverter is designed to deliver.

[mbarker]

Dimm down to the lowest brightness, and see if it stays on longer.
Old or defective CCFL at some point need more power than the inverter is designed to deliver.

Yes, this seems to be working to keep the display on longer.

Also, I have a parts machine with a working but damaged panel. What are my options for parts swapping? My technical abilities are pretty much limited to whatever I can do with a screwdriver.

[RealBlackStuff]

In that case, get another working LCD, or even a complete lid.

[gaphic2]

Success! I replaced the LCD-cable and the inverter, and the backlight and Thinklight are working again.
I have to commend the IBM parts service in Europe here too. About 24 hours after ordering, I got the delivery.

All of the posters here, thank you for your advice and support.