Need help with resistor replacement

[entomophile]

I am rebuilding the power supply in my arcade.  I am replacing all of the components.  If you look at the schematic, R5 is labeled as 25Ω, 5W.  The actual resistor on the board was a 13Ω, 5W.  The resistor is going to the input of the 7905 -5V regulator.  Which one is right?  I am leaning towards the schematic as some of the other old repairs on the board were butchered.  So maybe that resistor was replaced with the wrong one.  Or maybe STERN changed the circuit.  Anyone know which one I should go with?

[Slippyblade]

I'd say most likely the previous guy just dropped in whatever he had that was close to the value and called it good.  Go with the schematic.

[entomophile]

That's what I'm thinking, but I was hoping for an engineering answer.  Based on the specs of the 7905 and the -12v source voltage, which resistor value makes sense in the circuit?  I'm hesitant to blindly trust the schematic as C2 was missing from the original schematic (I added it in the pic)

[ed12]

c2 is a must
if u follow the circuit propley
u will see it is the main filter for the b+ reg's that follow it
the high ohm's resister is to act as a load for the input to the 7905
as they take there sweet ass time stablizing

ed

[entomophile]

I asked the same question on an electronics forum and got a good explanation of why the 13Ω resistor might be a better choice.

http://forum.allaboutcircuits.com/showthread.php?p=685350