Tuesday, June 21, 2016

Dewalt DW9118 Battery Charger Teardown

After 5 years I came into my workshop to recharge a battery on my portable drill.... only to find the charger looking rather dead.

I had hoped this would be a quick repair video, however it quickly became apparent that the unit had suffered a catastrophic failure: most of the silicon appeared to be dead.

After a look at the assembly quality and some choice made I de-capped the IC.  Such an attractive die... .this is a really old design: at least 20 years old!

Video of the tear down here:

Wednesday, June 15, 2016

Amazon's Right Angled Screw Driver and a Clever Suction Clamp

Sometime's Amazon's quality is a bit frustrating.  A rather nice kit of screw drivers for electronics repair... but the bit that I really needed had obviously been dropped at the factory and shipped on wards.   After pounding it straight and a bit of work with a needle file it was functional enough  to take out the two screws on the bottom of a broken iPhone.

On  the very much more clever area... a suction cup clamp thingy (hard to describe!).  Lot's of electronics uses clips which I find hard to open.  This clever gadget snapped open the case in one go with no damage!  What more could one want?

Amazon sources here:

screw driver kit link here

ScrewDriver Kit by MMOBIEL®

Clever LCD clamp thing here:


Sourcingbay LCD Screen Opening Plier Opening Cell Phone Repair Tools with Super Strong Suction Cup Platform for iPhone 5 5S
by Sourcingbay

Friday, June 10, 2016

Reverse Engineering a Circuit Board: Fiber Glass

If one etches away all of the copper and epoxy in a modern circuit board one is left with this:

It's a sheet of fiber glass.  A good paper on the technology of modern fibers may be found here:

This paper, from Altera, provide a great background on why fiber choice can be really important at the micro-wave frequency domain:  Altera_paper

Video on where this fiber glass matt came from:

Tuesday, June 7, 2016


Purchased the cheapest multimeter I could find so I could extract the integrated circuit.   A surprisingly simple IC!

The actual meter design was much as expected.  Poor attention to detail for higher voltages, concerning lack of fuses on current measurements... pretty thin feeling probe set.

Attractive die however!
more photos at: https://www.flickr.com/photos/electronupdate/albums/
Video of tear down here:


Sunday, May 29, 2016

The Surprising Bits inside a fuse

While doing some debug on a dead board I found a fuse that had opened up.

 One might think of a fuse as just being a bit of wire inside a cylinder.

However some fuses contain silica which converts to glass when there is a fault and the fuse just barely breaks open.  This is a clever bit of insight:  without the silica it's possible that an air gap could sustain the current as an arc defeating the fuse.

Molten glass, however, is an insulator.

Engineering shows up in everything!


The internet of things could not exist unless cheap semiconductors which implement tremendous functionality exist.

Extracted from the Philips HUE bulb in this video I take a look at the Atmel ATmega2564RF.

RF + competent processor section + Flash ROM + RAM... all for pennies.   Amazing!

Thursday, May 19, 2016

Philips HUE (2016) LED Bulb Teardown

The cheapest hue yet: only $15.00.  Finally cheap enough to tear down. This is Philips line of remote-controlled bulbs that support Zigbee. The zigbee controller has an 8 bit micro core... same one as the Arduino uses, I believe.

Much more credible to see an  8 bit process on a low-end consumer product.   The M0 on the Cree Connected bulb just seemed like over kill!

However, both bulbs sport a 4 Mbit serial EPROM.  That's a heck of a lot of storage (and cost).    Is there something in the Zigbee protocol which drives such massive data requirements.  Seems insane for a product which only can be turned on, off dimmed?