45 Watt mode not working

[AllanCWilliams]

Hi
My 45 watt mode is providing no output on my Mark V (all 3 channels). 10 watt fine (all 3 ch). 90 watt working (all 3 ch), but I think quieter. I presume I've got power tubes gone, but not sure which ones. Can someone direct me please to which positions provide what? Is there any other potential candidates?

 

[etepbbb]

If the amp works on 90 watt and 10 watt, but not 45 watt, I'd guess it's more then power tubes. You should have it looked at.

 

[fr0sty]

I believe 45 watt mode uses the inner two tubes. Try swapping those with the outside pair.

 

[loylo69]

Exactly! Quoting the manual:

In this setting (45W) only the middle pair of 6L6s are on.

One of the two 6L6s may have failed, you should try frOsty's suggestion.

 

[AllanCWilliams]

Thanks gents. Spot on. Switching the pairs confirmed the failed pair. Newies in place and all good since.