Following on alog 45653 and FRS 11921/10987 went down to EX to troubleshoot.

1. Power cycled PCAL chassis, temperature readbacks still glitchy.
2. Disconnected both the Transmitter and Receiver temperature sensors. Readbacks showing 0 counts.
3. Two spare AD590 sensors connected. Readbacks signals still glitchy.
4. Unit was brought back to EE lab. Output of chassis for temperature sensors both stable.
5. Unit was returned to End X.
6. Used 2 voltage calibrators and injected to Beckhoff, both readback signals stable.
7. Reinstalled cabling and power back up. Accidently connected shutter to temperature readback port causing the +15V to dim on front panel.
8. Power down and corrected cabling, power back on, tested shutter locally.
9. Both temperature sensors showing valid temperatures.

F. Clara, P. King