No, you can't. It may be faulty and need looking at but other than that, you are perhaps asking the amp to drive too many or too high resistance speakers. Check the amp specs and your speakers specs to make sure everything is ok.
how loud are you talking? regardless, you should be able to crank it all the way with those speakers and blow them before the amp gives up. There was a productions run of 7400s that had the A/B bias set wrong, causing the amp to run extra hot and shut down for thermal reasons. Call them with your serial number and see if they will replace it. You can also adjust the bias pots if you know how. Good luck!
Good luck!