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 1 (click to view)
RADIO CASSETTE RECORDER CD PLAYER
RCD-M30/30B/30G/35/35G
SERVICE
RADIO CASSETTE RECORDER CD PLAYER
SBS Repeat
ON/OFF
Manual
CONTENTS
1. Alignment and Adjustments 2. Disassembly and Reassembly 3. Exploded Views and Parts List 4. Electrical Parts List
Function Band
CD Radio
Radio/ CD OFF