Mystery Tool
The following photos show a measuring device that may or may not be IBM, and may or not be a CE tool. Here are some facts:
- The box has two handwritten numbers - 206256 & 2062564
- The meter face shows a logo "BL" and a number 3547860
- The thing that looks like a motor may well be a very sensitive meter movement instead. Applying a voltage to it made the needle move, direction dependent on polarity.
- The movement appears to equate to about 100mV to deflect to FSD
- Scale is marked in %, so appears to measure a deviation of + or – 100mV as a percentage of something
- At FSD the needle makes contact with the end stop, completing a circuit. The end stops appear to be adjustable.
Pin-out, International Octal base:
- 1 = meter needle (stop common)
- 2 = meter
- 4 = + stop
- 5 = - stop
- 7 = meter
Click to enlarge photos.