Hi i am using the ps100 with the friedman plex. I wanted it because i needed the fx loop and a volume boost for solos. Live. I got the ps100 the other day and hooked it all up just as it is supposed to be. Impedance correct. I noticed my friedman plex standby and power switches got really warm. Also the ps100 was hot. Then the ps100 lost sound after 1 hr of use. It blew the internal fuse. Plex is fine. One question the plex has a mvc do i dime that as well as the other volumes on that head with the ps100? Prob someone here who owns the friedman can chime in that know the amp. I am replacing the fuse and the 2 power tubes in the ps100. I want to use the plex live so i need some stage volume and boost for solos snd fx loop. Why i bought the ps 100. I noticed to the ps 100 volume at noon wasnt that loud. My plex was dimed
Hi Lee and welcome to the community 
Hopefully other Friedmann/Plex lovers will chime in…
How is the ventilation around the amp? I’m not familiar with that amp but it could just be getting hot inside so everything gets a little warm. This is probably fine. But it does make me thing that maybe you need a bit of air flow in the room to keep things cooler.
This is fine, you can put up to 200W into the Power Station.
Really normal use case too.
Yes, this is the right thing to do initially.
Can you see the PS-100 fan working and verify that is is moving air (only do this with the case closed for safety)?
When you have the case open to change the tubes can you please check components inside including the cables that connect between the different boards (green PCBs). You want to check for any signs of over heading (brown or burn resistors or melted plastic on wires).
If you have these issues then it might need a repair, hopefully it was just the tubes.
Regards,
Dan