While repairing a Marantz amplifier using the service manual, I came across resistors with odd symbols (see page 18). They are trapped between two parallel lines (for example, 3297).
Is this linked to the fact that this is a 0.33W resistor? A comment suggested it could be related to the way it's mounted to the board for heat dissipation, but I don't see any mounting difference between 3297 and 3283 (see picture below).
Furthermore, what's the difference between the "R" and "E" letters for 3293 & 3305. Don't they both mean "Ohm" ? Is there any reason for Marantz to use both notations in this diagram or is it just an inconsistency?