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https://university-of-waterloo-solar-car-team.365.altium.com/designs/4F041A85-6320-476B-BAA5-BC219D4A1B9F?variant=[No Variations]#design

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This program turns on all load switches so I was able to measure the following:

Table 1

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Ryan said that there’s no firmware reason for both Main_Pi and Spare_5V_2 to both be zero and he suggested to take a look at the I/O expander connected to both Main_Pi and Spare_5V_2 (which is U10 in this case). More specifically, the following pins: 13, 14, 15, 16, 17, 18.

After confirming that these pins are not shorted with one another, I powered on PD and measured the following (from U10):

Table 2

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At this point, both LED14 and LED17 still did not turn on so I decided to measure check the voltages of the input pins of U13 and U4.

So there must have been an issue with the components surrounding

EDIT THIS:

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i found out that led14 turns on when i pushed down on pin2 of U13 (fixed this by soldering)

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i find out that led17 turns on by probing pin 4 of R89 (most likely soldering issue)

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U14 (1, 2, 3, 4, 5, 6, 7). I checked for shorts between the pins (which there were none) so then I decided to measure the voltages.

Starting with U13:

Table 3

As you can see in red, the voltage at pin 2 is zero!!! It should be around 3.25 V which is what pin 6 (IN1) is at. While taking these measurements, by luck I found out that LED14 turned on when I applied enough pressure to pin 2; this means that the component lead was “floating” above the pad on the board so I was able to easily fix this by soldering it down. So when I powered on PD again, LED14 turned on.

Moving onto LED17 (connected to U14), I tried to apply the same strategy. This time, I applied pressure to pin 6 but unfortunately, LED17 didn’t turn on. This means that pin 6 was soldered correctly.

So I decided to measure the voltages of the input pins (of U14):

Table 4

Just like the table for U13, as you can see in red, pin 6 is zero!!! It should be around 3.25 V. But pin 6 is soldered correctly, so I needed to look elsewhere. In this case, I moved onto R80 which is the resistor array that is directly connected to U14.

Since LED16 turns on, I decided to measure the following (from R80):

Table 5

As you can see in red, the voltage at pin 5 is zero!!! It should be around 3.25 V; this issue again points to another soldering issue but where?

So I decided to measure the voltage at pin 4 (which is directly across pin 5) and found out that the voltage was zero. But it shouldn’t be zero since pin 4 is connected to the 5V_SPARE_2_EN net/trace, which is connected to the I/O expander (U10). From Table 2, the 5V_SPARE_2_EN trace is 3.3 V so this must mean that either pin 4 or pin 5 of R89 is “floating” (i.e. not soldered properly). By luck, I was able to create a solid connection with a test probe at pin 4 while I was taking the measurements in Table 5, so I knew that I needed to solder pin 4. After doing so, I powered on the board and LED17 finally turned on.

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Throughout this process, for some odd reason, LED22 randomly decided not to turn on, but this was easily solved by soldering pin 4 of R115 (same process for LED17).

(IGNORE FOR NOW):

• power_distribution

  • automatically detects as rear board (in minicom)

    • LED27, LED23, LED4 stay on

    • LED1 of controller board stays on

  • VBAT: ~13.5 V

  • V5: ~5 V

  • V1: ~3.3 V

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• smoke_bts7200

  • LED27, LED23, LED4 stay on

  • LED1 of controller board stays on

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• smoke_bts7040:

  • LED27, LED23, LED4 stay on

  • LED1 of controller board stays on

  • 

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