The Harman Kardon AVR51 Library provides free access to both the owner's manual and the service manual for registered users.
Identifies the Power Switch, Volume Control, and Input Selectors. Harman Kardon Avr 51 User Manual 134
These are reputable aggregators. Search for “Harman Kardon AVR 51.” You will likely find a 44-page PDF covering: The Harman Kardon AVR51 Library provides free access
Since you are looking for concise data, here is the numeric reference sheet you would find in the appendix of the manual (Section 1.3.4 – Specifications). Search for “Harman Kardon AVR 51
What does the “134” suffix mean in your search query? It typically refers to one of three things:
Harman Kardon AVR 51 is a classic piece of home theater equipment known for its high-current, ultra-wideband amplifier sections that deliver 100 watts in stereo mode and 70 watts per channel in a 5.1 surround setup. Whether you’ve recently acquired one from a flea market or found a unit in storage, the Harman Kardon AVR 51 User Manual
If you are searching for this specific page, you are likely attempting a repair. Page 134 might hold the key to identifying a blown capacitor or a specific transistor replacement that generic forums cannot provide.