Mesa 2:90 woes _ tubes not coming on

[Helmholtz]

Check heater voltage at tube sockets (should be around 6VAC). If missing, take out fuses and check for zero resistance. Don't go by looks.

[Yovan]

No heaters means they are not getting power supply. SO find out where it went.

I'm really not sure how to find this - I took the lid off and checked inside - there's power to the fan but that's all I'm able to discern by looking at it. Perhaps need to change the tube fuses anyway....

[Enzo]

No heaters means they are not getting power supply. SO find out where it went.

[Yovan]

So I've had a problem with my Mesa, the other day it was working ok but today switched in and no sound. Checked the fuses and they look fine, the tubes on the other hand were off, no glow or heat. I was slightly concerned about the fuses in the back, on the panel it specifically says use 1A and the fuses installed are 3A. I'm worried something more serious has blown down the line... anyway I'm really hoping that it can be fixed, any help or advice is greatly appreciated, thanks in advance.