A teardown and repair of a Valhalla 2701C Programmable Precision DC voltage standard from The Signal Path:
In this episode Shahriar examines a faulty Valhalla 2701C Programmable Precision DC Reference instrument. Valhalla Scientific’s 2701C Programmable Precision DC Voltage Calibrator delivers ultra-precision, ultra-stable DC voltage from 100 nanovolts to 1200 volts. This unit does not have a working front-panel LCD screen. Luckily, that problem is resolved very quickly.
The internal build and operation of the unit is briefly examined and the instrument is calibrated using a Keithley DMM7510 7.5-digit multimeter. It is possible to upgrade this unit to a more stable and accurate reference voltage generator or to add the reference current capability to it.
More info at The Signal Path homepage.