Part Number: TMDS64EVM
I recently acquired a TMDS64EVM (Board Revision: PROC101D) which is failing to boot. The board appears to be stuck in a "Standby" state where the main system voltage rails are not powering up.
Current Symptoms:
LD6 (12V Input) is ON (Green).
LD24 (3.3V Aux/Standby) is ON (Green).
All other LEDs (LD1, LD2, LD3, LD4, etc.) remain completely OFF.
The Main Processor does not get warm, and there is no output on the UART console (J26).
Setup & Power Supply:
I am powering the board via the J6 Barrel Jack.
Power Supply Used: Mean Well GST90A12-P1M (12V, 6.67A).
Cable: Rated for 6A.
Troubleshooting Steps Taken:
Hard Reset: Performed a full capacitor drain (unplugged power, held SW4 for 10s). Re-applied power with SW1 OFF, then flipped SW1 ON. Result: No change.
Switch Configuration: Verified SW2 and SW3 are set to default (or UART) modes.
Visual Inspection: No physical damage observed. Jumpers (J18, J33) are present.
Hardware Diagnostics (Measurements at U30 / LM5140):
Suspecting a power sequencer failure (similar to E2E Thread #1081696), I performed component-level measurements on the U30 controller area:
Input Voltage: measured 12.0V at the input capacitor near U30. (Power is reaching the chip).
Output Voltage: measured 0.0V at the output inductor. (Regulator is not switching).
Output Impedance: measured ~350 Ohms from the output inductor to Ground. (This confirms there is NO short circuit on the load side).
Conclusion:
Based on the measurements, the U30 controller appears to have failed open (receiving 12V but outputting 0V) despite the absence of a downstream short circuit.
Could you please confirm if this indicates a permanent hardware failure of the PMIC/Buck Controller and if I should proceed with an RMA?
