The amp had output stages in both channels shorted. It turned out that 5 out of 16 power transistors failed. Driver transistors on the negative side in each channel failed as well and killed a couple of 6.8 Ohm resistors around them. After unsuccessful attempt to get cheap transistors from China on eBay, the amp was tested with 8 out of 16 output transistors in the output stages. This configuration worked fine, and now the question is about money: if we tolerate mixing old and new transistors, 5 replacement transistors from DigiKey will cost about $40. Replacing all 16 will be (almost) beyond economical repair. Let me know what you think. Thanks. ... https://www.youtube.com/watch?v=c3G79R8Gcrw

Silicon Labs Si7051 was used to build a 0.1 degree C accurate thermometer with a serial port over USB. A small 0.96" OLED display with SPI interface was also used, as well as Atmel ATMEGA328P micro-controller. The software was written using Arduino development environment and Adafruit_SSD1306 library for OLED display. Si705x data sheet: http://www.silabs.com/Support%20Documents/TechnicalDocs/Si7050-1-3-4-5-A20.pdf OLED display library: https://github.com/adafruit/Adafruit_SSD1306/blob/master/Adafruit_SSD1306.h Arduino sketch: https://github.com/sandy-s/Si705x/blob/master/m328p-spi-oled.ino Discussion: https://www.eevblog.com/forum/metrology/precision-thermometer-for-data-logging/ ... https://www.youtube.com/watch?v=pj1HOM35vH4