A variety of electronic hardware information related to design,
repair, troubleshooting and equipment.
Bi-directional level-shift with MOSFETs
While doing some background reading on the Philips Semiconductor I2C bus I came across one of their Application Notes
written by Herman Schutte. The note describes how to use N-channel enhancement mode MOSFETs to create
a bi-directional level-shifter for use with the I2C bus. I decided to try using this elegant MOSFET circuit to
interface a 5V LCD module to a 3V controller.
Nikon E990 dual USB/Serial cable
This page provides
information about how to modify the supplied USB cable to make a dual-use USB and serial cable. This
information can be found in the camera work section.
A built-in DIN 8 for the MP2100
Some information on how I used an ugly hack to add a built-in DIN-8
serial connector to a Newton MessagePad 2100.
Macintosh 9500 - lithium battery, power supply
The Macintosh 9500 computer includes a Lithium battery
which supplies power to the PRAM when the computer is not plugged into AC power. This battery is not rechargeable
and needs to be replaced from time to time. This page
describes the procedure for replacing the battery as well as growing list of alternative replacement battery models.
I am also looking at repairing or replacing the 9500 power supply and will add notes about this once it is complete.