TDA4VM: Proc079A development board cannot be started. LD3 is flashing, but the external input power is 12V

If LD7 is on, then input power is getting to the system.  Have you recently install a new SOM module, or have you been using the same SOM and this issue just started happening?  Often when we see LD7 ON but LD5, LD6 OFF the issue is with the SOM installation.

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At present, the development board is completely in the original state and has not been moved. Is in the process of using suddenly unable to start.

I would like to confirm whether you want us to replace a som module. If so, could you please give a specific model and the bit number of the development board

If the board was working for a period of a period of time - it is likely not the SOM module.  However, you could still try to remove and re-install.  Is possible it was bumped loose or something.

If that doesn't work - it sounds like the board was possibly damaged some how during use.

How do you handle E2E if they can't solve it remotely, how do you replace it

Since the board was likely damaged during use - another system would need to be purchased.

We did not have any damage in the process of key use, how can one of them be done? Should you check the hardware first, and could you help us to replace a new one now.

Have you tried removing and re-installing the SOM module?  If it was loose to begin with, then possibly a bump caused the board to start failing.

TI does not warranty the EVMs once they have been used. 

We just power on and use sd cards, and nothing else inside has been touched. If you think we have moved or changed something on the board, we can send it back for inspection. Please confirm the handling method, our internal R&D colleagues have been waiting for a reasonable solution.

TI does not support warranty or repairs on its EVMs.  What input supply are you using?  Do you have the ability to probe around on the board with voltage meter to see if we can determine which power rails is not working?

kindly find below photo1: we Use DC regulated power supply,

 photo 2：use dc head access development board ,

Where do we need to measure to help you make a judgment about the power source? The status of the led light has been photographed,kindly advise,thanks.

Connect DC power supply with 12V at input.  With the EVM's power switch in the OFF position, what voltage do you measure on test point TP19 and TP20.  Repeat same measurement with EVM switch in the ON position (voltage on TP19 and TP20).

According to the test,before the switch is turned on, tp19 11.72 tp20 0v, tp19 and tp20 are both 12V.

Maybe you should say more about the points that need to be measured at one time. Otherwise, communication once is a day, which is too inefficient。

Ok - so input power circuit is working.  Next step would be to check the first stage power regulator: TP35 or TP130 should read 3.3V.

The next step in the power tree is the PMIC on the SOM module. The enable to the PMIC should be logic level HIGH (TP130 on the SOM)

The PMIC then begins to boot its supplies.  If it detects an error (like regulator short to GND or overcurrent), it will shut down.  When it does this - its sets EN_DRV bit low (TP105 on SOM)

The PMICs internal regulators are TP129 and TP132 (both on SOM).  Both should be 1.8V

You can measure the 3.3V power rails at TP131 and TP133 (both on Common Processor Board).  However - I suspect these are 0v based on the LED description. 

tp35 and tp130 3.3v
tp105 0v
tp129 and tp132 0V
TP131 and TP133 0V

The PMICs internal supplies are not operational (TP129, TP132 on SOM).

Did you measure the PMIC enable? (TP130 on SOM) 

I previously asked if you had removed SOM and re-installed (to confirm the SOM is correctly installed).  Was this done?

TP130 has been tested, the last message sent to you contains the voltage value of TP130 test point, TP130 is 3.3v voltage, ，I have inserted and removed the SOM941x module and the phenomenon is still the same (small board fixed by four screws alone).

I removed the SOM, and I could still hear the inductance hissing from the bottom

The 'hissing' you report may be coming from another supply (12V)...I think its the only other supply that is enabled when PMIC is OFF (TP39).

I'm not sure I can explain the measurements.  The first stage 3.3V regulator is operational (TP35).  The PMIC enable input is set to active (TP130 on SOM is 3.3V).  However - the PMICs internal regulators are not active (TP129 and TP132 on SOM are both 0v)

Maybe the safety FET is damaged?  Can you measure TP128 on SOM?  It should be 3.3V.

I'm sorry that there was a mistake in the previous reply. I understood the test point on SOM as the TP130 of the bottom plate,
so I measured the test point on SOM again, as follows:

TP105 on the SOM： 0V
TP130 on the SOM： 0V
TP128 on SOM ： 3.3V
TP129 on SOM ： 1.799V
TP132 on SOM ： 1.799V

TP130 on SOM is 0V...implies PMIC is not getting enabled.  What is status of SW1 on SOM (2bit dip switch on SOM)?  Bit 1 should be ON, Bit 2 should be OFF.  Try toggling the switches just to make sure they are set correctly.

SW1 on SOM  1 is ON   2 is OFF, so Could you please apply for replacing a set of development board for us。

I am sorry, but I believe I've already answered this question.  Since the board was likely damaged during use - another system would need to be purchased.

Now, according to the current measurement information, can we confirm the abnormal power supply on which board the problem occurs

The latest information indicated the TP130 (on the SOM) read 0V.  As mentioned - this indicates the PMIC is not getting enabled.  SW1 position 2 is confirmed to be OFF....thus the EVM should NOT be purposely disabling the PMIC.

Did you check TP107 on the Base Board?  This is the signal from the base board tell the SOM to enable the power (PMIC).

TP107 on the Base Board is 0V

TP107 is sourced by device U129 on the base board.  Can you probe pins 1, 3, 6 on that device - that should tell us which part of the base board is tell system to NOT start. 

1.U129 on the base board： pins 1, 3 is 3.3V, but pin6 is 0V
2.U32 on the base board： pins 1, 6 is 3.3V, but pin3 is 0V
3.R209 R212 on the base board also is 0V
4.R97 on the base board：VSYS_3V3 is 3.3V ,LM5175_PG is 0V
5.R97 on the base board：VSYS_3V3 is 3.3V ,LM5140_PG1 is 0V

Maybe an issue with the on-board 5V or 12V regulator?  What is TP39 on base board (should be 12V)?  What is TP26 on base board (should be 5V)?

TP39 on base board is 5V   tp26 on base board is 0V ,and   C110/C100 on base board （Vinput）is 12V

I think TP39 should be 12V (not 5V), either way it appears the 12V on-board supply is not working.  The 12V supplied is optional for the add-on PCIe modules and is used for some of the audio codec amplifiers. If you don't use any of these peripherals, you might be able to remove R212 on base board to bypass the issue.