Probably it never existed a 1081 official service manual from Commodore, it's look more like a NAPCEC service manual & diagrams compilation of the 1084 series and his variants, like the nap6523, 8cm505, 1084S, 1084P and obviously the 1081. It's more complete than other scans and the quality of the scans also are far superior. It has two circuit diagrams variants of the 1081, mono and stereo versions. It doesn't include a diagram for the Philips CM8500 or CM8501, they look like the 1081 but they are slightly different.
Text excerpt from page 43 (click to view)
7 Troubleshooting
7-2-7 Poor Focus
Adjust focus VR.
Improved focus?
Yes
Aging monitor and check for focus change.
No Check focus leads from FBT to CRT Socket.
Check the CRT Socket.
Is dynamic focus circuit right?
No
Refer to 7-1-15 Dynamic Focus Failure.
Yes Replace the CRT and verify focus.
7-2-8 Purity Failure
Degaussing
Purity is right?
Yes
Done
No Degaussing circuit is right? No Refer to 7-1-20 Degaussing Failure.