Conrad Johnson Premier 140 fuse is blown

Put a cheap fuse in and retry, worst to happen is it will blow it again, then call the tech.

Change the fuse and see what happens. The fuse is there to protect the unit. If it blows again, the amp won't be damaged but you should then get it checked out.

Straight from the CJ Premier 140 manual:

What happens when the fuse blows? If one of these fuses should blow, it usually indicates a marginal output tube (one of four for each channel odd numbered tubes for the right channel, even numbered tubes for the left channel) and an attempt should be made to identify and replace it, by either (a) replacing the fuse and turning on the amp while watching the output tubes carefully; look for a bright white or blue flash inside the tube. If nothing happens, then (b) lightly tap the output tubes one by one with the plastic handle of a screwdriver while watching for flashes inside the tube. If efforts to identify the bad tube fail, the best course of action is to replace both tubes in the channel that blew the fuse. If the tubes are over two years old, or have more than 1,500 hours on them, a complete replacement tube set is probably in order.

Thank you all.
I will order a set of tubes and the fuse. Hopefully everything will be fine after those replacements.
Calvin

If it was a fault in the fuse.

You must check at least with a meter or any signs of damaged components, likely resistors or whether any tube is bad.

Likely, a tube or more has shorted. This takes out some other components around the faulty tube and this short will take out the fuse.

There is only a very small chance it will work by just replacement, lest the time the new fuse blown again,  can take out more components.