Have you tried a Factory Reset, or tried hooking it up to your computer and seeing if it connects with the Blackstar Insider software? Do the interface buttons and indicators on top light up? If you have the footswitch, does the display light up?
If you don't have the Owner's Manual, you can get it here:
https://www.blackstaramps.com/pdf/handbooks/id-core-high-power-handbook.pdf
And the Insider software here:
http://www.blackstarinsider.co.uk/
If the buttons and indicators light up as if things are normal, check the input jack; it may be that the jack itself or the connection has gone bad or gotten disconnected, especially if anyone has tried to poke around in there. From what I read of the Owner's Manual, the power section is disabled if there isn't something plugged into the Input jack. The fact that you can get power output without having anything plugged into the Input jack (or do you? I'm making an assumption...) tells me the jack or the connection may be bad.
If the Factory Reset doesn't do it, or if it can't connect to your computer with the Insider software, or if the buttons and LEDs don't light up, then your preamp (and all the digital effects and gizmos within it) is most probably toast. Digital stuff is either working or permanently broken. Either scrape up the money to get it fixed by an authorized dealer, or use the power section as a means to amplify your coolest pedals.
If you don't have the Owner's Manual, you can get it here:
https://www.blackstaramps.com/pdf/handbooks/id-core-high-power-handbook.pdf
And the Insider software here:
http://www.blackstarinsider.co.uk/
If the buttons and indicators light up as if things are normal, check the input jack; it may be that the jack itself or the connection has gone bad or gotten disconnected, especially if anyone has tried to poke around in there. From what I read of the Owner's Manual, the power section is disabled if there isn't something plugged into the Input jack. The fact that you can get power output without having anything plugged into the Input jack (or do you? I'm making an assumption...) tells me the jack or the connection may be bad.
If the Factory Reset doesn't do it, or if it can't connect to your computer with the Insider software, or if the buttons and LEDs don't light up, then your preamp (and all the digital effects and gizmos within it) is most probably toast. Digital stuff is either working or permanently broken. Either scrape up the money to get it fixed by an authorized dealer, or use the power section as a means to amplify your coolest pedals.