A couple of weeks ago, I posted about fixing my son's laptop that stopped charging the battery and running off of the A/C adapter. I had isolated it to one component on the motherboard that I thought was a capacitor and took off to find a schematic or at least the part value.
Turns out the part was actually a ferrite chip. That makes the measurements I made pretty worthless when I was assuming it was a bad cap. Anyway, thanks to a remarkably quick response from ghn on http://www.notebookforums.com/, I was able to find http://lqv77.com/downloads/ which had a schematic for the laptop. From that I found that the part in question (FL1) was a ferrite chip BLM41PG600SN1L. I found it on Digikey.com at 0.54 for quantity 1. Of course I bought 5 - they are cheap and worth having on hand for future designs and repairs. Well, that and about another $50 worth of parts that I had on my wishlist for future projects.
I decided since it was not completely clear that the capacitor PC134 (.01uf 25v Ceramic in a 0402 package) wasn't a problem, so I replaced that also.
My hot air rework station came in handy for this. I cleaned up the pads with some additional solder and flux to get it to flow, then removed the excess with desolder braid. Soldering the ferrite chip (a 1806 package) was a piece of cake. The capacitor - not so much. The 0402 package is really small, making it ridiculously hard to hold it in place. I really need to get some really good tweezers to work with parts that small, and maybe a syringe of good solder paste for reflow soldering.
After a bit of fumbling, I managed to get it tacked down, then used the hot air to reflow it. I cleaned up the excess flux with some alcohol.
I connected the battery, and power switch board, then plugged in the power. The charging light came on, which I counted as a success.
It took me an hour or so to carefully reassemble the laptop, which has worked perfectly ever since.
For details on the troubleshooting process, see my previous post
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2 comments:
Great blog! I not only my eyes it is well written purely, How easy is it to information. Wondering how to notify me when new posts are made I. I subscribe to the RSS feeds you should do the trick! Have a nice day!
National Power Supply
Thank you, Vince. I ordered an used mother board and maybe didn't need it. I don't do a lot of electronics any longer, but as I'll have to remove the old mother board any way, guess I'll suit up for some diagnostics. Now, where'd I put my Fluke - lol.
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