LCD GURU's Please Need help identifying a problem

[moebiius]

Specs: t-42 2373 k5u
initial problem....I thought that by inverter was bad but from what i've read here it deemed to be a bad backlight...so I replaced the whole LCD with one that I know works with an inverter that I also know that works.

Problem...before it would fire up and the inverter lights blink and stay on even if the LCD was barely lit...now the [censored] thing is that the inverter lights blink on when i press the on button but would only stay on for maybe 3-4 seconds and the cpu fan would spin up but spin down right after.

please help me out, I love my thinkpad.

Ken

PS. new LCD is LP141x14 tested and pulled it out of an existing bs dell I had laying around.

THANKS FOR YOUR ATTENTION GUYS!

P.S.S. oops sorry about that, forgot to mention that it boots with an external monitor just fine and the inverter light it on as well as the cpu fan is spinning normally.

[Harryc]

If you disconnect the LCD from the systemboard at it's connector, and hook up an external LCD or monitor, does the machine power up normally and does the fan run? I have heard that some LCD's that are non-Lenovo parts can blow a fuse if you hook them up because of differences in pin assignments. I hope this is not one of them.

[moebiius]

this model LCD from my POS dell is the same as my IBM/Lenovo part. Anyhoo, when I ran the external monitor, i didn't disconnect the LCD cable, is there a reason I should have? Please explain since i don't understand why it would work and then not work....could it be that the LCD cable is loose? could it be the connecting point to the mainboard thats loose?(then again, I didn't take that part of the computer apart).

[ajkula66]

You've blown the fuse on the board in the very best of all the possible scenarios...

[moebiius]

any way to check if its blown or not? is possible to see if its blown with the naked eye? and where would it be located? and how the heck did i manage to do that?

[Harryc]

Check the fuses around the LCD connector. You will need a multimeter.

[moebiius]

On the mainboard? Or LCD itself? And what should I be measuring for with the multimeter? Thanks again for your help and patience. Does the hardware maintenance cover this as well, on the component level?

[Harryc]

Yes on the systemboard. The maintenance manual does not cover component level repairs on the systemboard. You need to do a continuity check across each of the fuses with the multimeter. Contact member poshgeordie on this forum for a fuse location list. There used to be a working link in his sig, that no longer works.

[sjthinkpader]

George is correct. Dell uses different Vcc and GND pins and either the MB fuse or the panel fuse is blown.

[moebiius]

thanks gentlemen, i really appreciate the efforts!

ken

[moebiius]

Searched poshgeordie and links are too old, anyone with new links or pictures of where the fuses are located at or what they look like? I'd really appreciate it.

[Harryc]

Send poshgeordie a PM (private message) on this forum and ask him to update his links...or email him at nick@reflowrepairs.com

Edit: I just tried it and it works for me ...
http://nickpaton.fireflyinternet.co.uk/ ... 0Fuses.pdf

[moebiius]

Thanks it works now! Thank you very much