1. Home
  2. Electronics Repair
  3. Toshiba Satellite Pro M15-S405 PCB flux rot

Toshiba Satellite Pro M15-S405 PCB flux rot

Here's one I haven't seen before:

It's the motherboard from a Toshiba Satellite Pro M15-S405 laptop. The brown crud is probably flux left over from the soldering operation or something corrosive, that was trapped between the PCB and a thin plastic "protective" covering under the DVD drive. The board acts totally dead. No power, no charge lite, no sounds, no nothing. At first, I thought that someone had spilled some liquid into the laptop. Nope, because all the corrosion is BETWEEN the PCB and the plastic, with nothing on top of the plastic. The plastic covering was totally clean. There's no corrosion in the area that's NOT under the "protective" covering, so it seems whatever did the damage, was volatile.

The customer has 3 other identical laptops. I just inspected them (through the DVD slot), and found no corrosion.

I'm not sure I'll be able to fix this one as the rotted traces in this area are very tiny. It's probably not worth the effort for a 9 year old laptop.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com               jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS
Reply to
Jeff Liebermann
Loading thread data ...

One more photo:

-- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831-336-2558 #

formatting link
snipped-for-privacy@cruzio.com #
formatting link
AE6KS

Reply to
Jeff Liebermann

Liquid might have landed on the PCB but then wicked between the plastic sheet and the PCB, where surface tension held it in place.

The surface area of any trapped liquid is relatively tiny.

The corrosion is not bridging the traces? Is the corrosion conductive?

Reply to
spamtrap1888

Nope. Look at the photos. Most of the rot is in isolated patches with no fluid connections to the edge. Also, the "protective" plastic sheet has some kind of glue smeared on one side, covering the entire area. It will take considerable effort to remove it. I don't think anything can creep underneath (including capillary action).

True. It also took years for the stuff to finally eat away the copper. Mostly, it ate the areas around the PCB vias (holes), which again points to something during manufacture. Probably a tiny amount. Were it not for the "protective" plastic trapping the stuff, it would have probably evaporated away.

I can't tell yet. It's definately eating away the traces because the failure is lack of on/off and lack of charging (so far). Bridging would cause other problems. Incidentally, I checked all the fuses and power buses. They're fine.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com               jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS
Reply to
Jeff Liebermann

"Jeff Liebermann" skrev i en meddelelse news: snipped-for-privacy@4ax.com...

From what I can see the PCB is flipped over (upside down). Liquid (cola?) might have landed on the top surface and then it is wicked through the PCB through the via's to the bottom side where it gets trapped in between the PCB and the plastic covering. Have seen almost the same with a Logitech keyboard. The liquid that landed on the top surface was free to evaporate. The liquid on the bottom surface was trapped and could etch away :-(

--
Uffe Bærentsen
Reply to
Uffe Bærentsen

Correct. It's a bottom view.

Maybe. There's another sheet of plastic on the other side with holes for connectors and mounting studs. I didn't see anything odd looking through the plastic, but I didn't peel it off yet. When I get back to the office on Monday, I'll take a closer look after I peel off all the plastic.

Good point, if it happened that way. I'll double check.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.