Part of the week: LT8554 and on the art of cell balancing

This week’s part of the week is a Linear Technology’s LT8584. The part is a DC-DC converter that is designed for a very specific purpose- active balancing of battery cells. In a typical long battery string, no matter how tightly matched initially, there will always be cells that end up with a bit more or a bit less charge. Over time these imbalances start affecting what the battery can deliver, as one week cell may trigger undervoltage limit for example and shut the whole pack down despite other cells being perfectly happy. Continue reading

Philips Sonicare HX6710 teardown and repair

Today we have a new subject to tear down- my own Sonicare toothbrush. At the end of a brushing cycle it made a short “Beep” noise and went silent. No reaction to button press or to putting it on a charger. No lights, sounds or anything. Oh well, might as well take it apart.

Philips Sonicare

Philips Sonicare

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Testing laptop battery: pinout, SMBus, charge capacity

Introduction:

As a result of visiting Hamfest, I ended up with a laptop to take apart – a fairly new Toshiba Satellite C675D with a broken screen. It’s not a Hamfest if you don’t bring home something to take apart of course! Today we’ll be testing the battery it came with to see if it’s salvageable.The date code says  it was made in 11/2011

Patient all hooked up

Patient all hooked up

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2013 Rochester Hamfest at RIT

It’s been year and the RIT Hamfest is once again upon us. A few pictures of interesting things we stumbled on. I can’t claim to know what some of them are though!

Eagle Aspen DISTAMP-25-GX teardown in pictures

This unit was used for a few years with a very limited success until I finally got fed up and decided to peek inside. The always warm case and constant 7W power draw did not help its cause either. As one of the 2 star reviews on Amazon concluded- don’t bother buying one of these.

 

Vintage DMM- Hioki 3200-50

An ebay find made its way into the lab- an industrial quality DMM from Hioki, made in 1984! The meter has some pretty good specs as shown in this datasheet:

  • 3.5 digit (1999 count), 0.5% on DC voltage
  • 20uA DC current range with 10nA resolution
  • 1G input resistance on 200mV range
  • Drop proof to 1 meter
  • Dust sealed.
  • 500 hours battery life using 2 AA
  • Neon indicator of overvoltage Continue reading