Next up just follow each wire in the power supply to check each of it's connection. Sometimes it is just a wire that has come loose or a dodgy solder connection. The best way is to look over it in sunshine rather than under a light inside your home, a cheap magnifying glass can be helpful as well.
One thing to make sure of is that you have left enough time to ensure any residual charge in the caps has had time to reduce to nothing. If you have not got a DMM yet, then get one and use the voltage range just to check there are no charges left behind before poking any fingers into the works. Tube amps work on high voltages so ensure you stick to these basic safety precautions. You can pick up a basic DMM for around $10 these days that work well enough for such basic checks.
Bluesky
