I won't say not to replace it because if something happened I would not have wanted to be the one who said not to..
But:
Curious,is the Fan in the Power Supply..... or Connected to the wood in the cab itself.?.......A seperate fan..
My Big Red and Neo Gold have Fans in the Power Supplies..If these go I will replace them.
The Klax mini cab has no fan in it though It did have one as I can see..
I have a fan for it that I'm going to install(only because I have the fan and the cab is not well ventilated)..The power supply in that cab is fanless..
The Tekken 3 has no fan and I'm not putting on in it because it has a lot of ventilation..(..The power supply in that cab is fanless)
The Candy Cab however has a spot in the back for a fan so I took advantage of that and installed one that blows the air out..
That cab never felt warm inside but this fan really keeps it cool..
My Big red after and hour gets warm inside and I'm glad that it has a blowing out fan in the power supply.
At one time I had a big Fan inside that cab cooling it down because I was in fear something would heat up and blow out..(A nervous noob).
I'd say if your not leaving the cab on for long and the Fan is not in the Power suppy then you may be ok..