With some old Junos release, PTX1000 STS LED is off even Junos OS has booted due to RE FPGA firmware.                         

PTX1000 runs Junos 17.4R2.4, the Chassis Status (STS) LED on the management panel of the chassis is unlight (Off) , which would be light with green color on steadily.

user@PTX1000> show chassis firmware
Part                     Type       Version
FPC                      U-Boot      ***
                         loader           FreeBSD/i386 bootstrap loader 1.2
                         BIOS       V0018.8Y
                         EC FPGA    2.3
                         MAIN_CPLD  1.17
                         MEZZ_CPLD  1.17
                         RE FPGA    2.5

The issue id due to firmware of RE FPGA 2.5, which addresses by PR1332991, check the PR for the fixed releases, refer to TSB17421 [juniper.net] for the RE FPGA firmware upgrade.