As written by windrider42, there is no Rogero CFW 3.73. Only a spoofer for CFW is available and this should be reset before you make a downgrade. Otherwise, you risk a red screen when you try to downgrade. Have you enable QA flag?
Tristate must only install if you use a hardware flasher. That your PS3 shows no reaction is normal as this is doing exactly as it is otherwise not possible to flash the PS3 without an external power supply.
In normal use this contact must be opened again. If you do not know what CFW is on it, you should use a DOWNGRADE.PUP, like Rebug 999Downgrader or Rogero Downgrader.
Please let us but how did you proceed to your PS3 to downgrade if you use a flasher and if what hardware you use?
If you Brick your PS3, the only way to bring it back is a hardware flasher like Teensy (NOR), Progskeet (NOR and NAND) or so.
Hope can help