Who can upload the service manual of this model ?
some URLs for reviews and various internal images:
https://audiolife.pl/yamaha-a-s1100/
https://de.yamaha.com/de/products/audio_visual/hifi_components/a-s1100_g/features.html
https://jp.yamaha.com/products/audio_visual/hifi_components/a-s1100_g/index.html
https://www.lifewire.com/yamaha-s1100-amplifier-1846255
https://www.lowbeats.de/test-vollverstaerker-yamaha-a-s1100/
P.S.: Service-Manual from Yamaha's power amp model "M-5000" is here:
https://elektrotanya.com/yamaha_m-5000_pwr-amplifier_sm.pdf/download.html
https://de.yamaha.com/de/products/audio_visual/hifi_components/m-5000/index.html
same circuit topology for the power amp unit than A-S1100
some URLs for reviews and various internal images:
https://audiolife.pl/yamaha-a-s1100/
https://de.yamaha.com/de/products/audio_visual/hifi_components/a-s1100_g/features.html
https://jp.yamaha.com/products/audio_visual/hifi_components/a-s1100_g/index.html
https://www.lifewire.com/yamaha-s1100-amplifier-1846255
https://www.lowbeats.de/test-vollverstaerker-yamaha-a-s1100/
P.S.: Service-Manual from Yamaha's power amp model "M-5000" is here:
https://elektrotanya.com/yamaha_m-5000_pwr-amplifier_sm.pdf/download.html
https://de.yamaha.com/de/products/audio_visual/hifi_components/m-5000/index.html
same circuit topology for the power amp unit than A-S1100