SR 7300 broken volume knob
How do you fix a SR 7300 broken volume knob?
Is your volume control knob physically broken or is the volume control just not functioning properly?
If the knob itself is physically broken then here are the Marantz part number(s) for the knob (in bold) taken from the service manual (from the link below) for your receiver,
030B BLACK 03AJ154010 KNOB MASTER (BLACK) 03AJ154010
030B GOLD 03AJ154020 KNOB MASTER (GOLD) 03AJ154020
Unfortunately a search online using the part number produced no results.
However if your volume control (it is known as a ' volume control rotary encoder') is just not functioning properly then you may be able to repair it yourself.
Here is a link to a video which shows how to fix the problems caused by a 'dirty' rotary encoder. Be careful that you do not bend the splines of the encoder when you are cleaning it.
If you cannot repair the rotary encoder here is the part number for the encoder (in bold). Replacing it means that you will have to un-solder the old encoder unit and re-solder the new one onto the pcb.
ROTARY SWITCH ROTARY ENCODER C12E 24PULSE SR02010090
Here is a link to just one supplier of the part. Just search online using only the part number, nothing else to find other suppliers that may suit you better.
Hopefully this is of some help.
Ensure that if you are going to open your receiver so as to access the rotary encoder, that you totally disconnect the power from the unit, as there are lethal voltages inside the unit.