Meter check of the UDN6118 display drivers
Steps
- Unplug the display.
- Black (ground) lead on UDN6118 pin 9.
- Pin 9 to pin 10: open or very high resistance.
- Pin 9 to input pins 1-8: about 30K to 45K ohms.
- Pin 9 to output pins 10-18: about 110K to 130K ohms; readings should be similar with the leads reversed.
- Compare with a known good display, as meters differ.
Systems
Related tips
- Seven-digit display board (A14) parts
- The display voltages to check
- Telling a bad display driver from a bad display tube
- How the Gottlieb fluorescent displays work
- Measuring voltages on a display board
- Checking the +60 V filter caps on a display board
- Replacing a display glass tube
- How the System 80 fluorescent displays light
Source: Troubleshooting Gottlieb Displays (On Target technical newsletter, vol. 3 issue 7, 1982), Gottlieb "On Target"