12 Keysight M9195A PXIe Digital Stimulus/Response Service GuideHigh-Level Diagnostic Tools, Processes and References– "Ltc2261 test failed"See “Chassis Cooling Checks” on page 6. If problem persists, see“Returning a Module for Service” on page 22.– "Ltc3880 test failedSee “Chassis Cooling Checks” on page 6. If problem persists, see“Returning a Module for Service” on page 22.– "Max1031 test failed"See “Chassis Cooling Checks” on page 6. If problem persists, see“Returning a Module for Service” on page 22.– "Max621 test failed"See “Chassis Cooling Checks” on page 6. If problem persists, see“Returning a Module for Service” on page 22.– " Carrier FPGA Version ( rev>) isearlier than minimum required,"Return any prototype M9195A modules, see “Returning a Module forService” on page 22.– "Reference Clock PLL has lost lock; selected source is Front Panel / PXI 100>"If the problem is with the PXIe_DStarA trigger, reassign reference clockand re-try. If OK on another source, check the source of the PXIe_DStarAtrigger.If the problem is with the Front Panel source, disconnect it and check itwith an oscilloscope.If PXI 100 is indicated, check diagnostics available for the chassis.