sub-card problem?

[somae]

We've got a 600x thinkpad that's been having a display problem. (I posted about this in the "how to" forum.) It seemed like it was a problem with the sub-card switch. I removed the switch and soldered the "on" terminals together and that functioned for quite awhile but then the display started having the same problem again - not staying on after boot, or staying on a litttle and then going off. Now it flashes on and off 5 or 6 times and then goes off..

I think there may be a scratch across the printed circuit on the sub-card..

Also, the plug for the speaker? came loose from the cable when I tried to pick up the keyboard.

Help appreciated.

[rkawakami]

If you have eliminated the lid switch from cutting off the power to the backlight, then there's still a couple of things which can affect that light source:

- the backlight itself is getting to the end of its life
- the inverter board, which provides the necessary power to the backlight is going bad
- a loose connection anywhere between the motherboard and the backlight
- a problem contained on the motherboard

If you believe that there's a scratch across the trace(s) on the sub-card, you can gently scratch off the solder mask (the greenish material which has been "painted" on top of the board) to reveal the copper trace. You can use something like an X-Acto knife or small flat screwdriver. When the copper is exposed, flow some solder across the gap in the trace and that should fix it.

Fixing the speaker connector might be hard to do since you'd have to re-solder the connector onto the mylar ribbon cable. Just so happens that there's a speaker set w/cable on eBay at the moment:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0390773650 ($15)

You might also be able to find the entire palmrest/keyboard bezel assembly for around the same price (or cheaper):

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0067293218 ($10)