Good new:
Drive arrived quickly. No problem installing it and getting an empty 25 HD hours, or going back to the original drive. Just as scn101 described.
Bad news:
I guess I expected the drive to come with a SATA cable - all the other's I've purchased have (but they were "retail box"). I don't want to touch the seal on the existing drive, but rather take SATA outside. I had a spare SATA data and power cable, but the power is the regular 4 connector molex you'd see in a PC. 942 has an odd 5 connector with no wire in the 5th, so I had to use its 2" power connector. I guess I'll need to purchase a SATA to eSATA and external enclosure with its own power and fan.
Worst News:
Should have been obvious if I thought about it, but with the empty drive, there were 80 missing Timers. I didn't use the new drive for long as recordings were going to start soon. I'll need to write down the existing Timers to recreate on the new drive when I have more time.