Jeff, Richard, Dave:

I installed two new 16bit DAC cards in h1sush56's IO Chassis. To maintain an 18bit DAC bloc, followed by a 16bit DAC bloc, I moved the 5th 18bit DAC to a slot with a lower address (details and drawings updates will follow).

After the upgrade h1sush56 could not see its chassis. I noticed that when I powered up the chassis (first back switch, then front switch) the LED above the front switch did not turn on. Also the LEDs on the one stop card flashed but did not stay on. After switching one-stop connections between h1sush56 and h1susauxh56, I homed in on the chassis as being the culprit. Richard suggested a possible power issue due to the increased loading. I removed the new 16 bit DACs and returning the 5th 18bit DAC card to its original slot, I still had the error. So it was looking more like the 16bit-dac-interface cards were the cause of the problem. For a quick test I unplugged the power line to the interface bus and the problem went away. I removed the two new interface cards one at a time and found that the card with S/N S1500322 was the problem child. After replacing the bad interface card, re-relocating the 5th 18bit DAC, re-installing the two new 16 bit DACs I was back on track.

On the software side, I modified h1iopsush56 to add the two 16bit DAC cards. Jeff modified h1susomc to add the OM1,2,3 tiptilt controls (using the first of the two new 16bit DACs). After model restarts, watchdog untripping and a DAQ restart at 16:57PDT the upgrade was completed.