Author Topic: ATXRaspi R3 does not power on [solved]  (Read 762 times)

smoove

  • NewMember
  • *
  • Posts: 7
ATXRaspi R3 does not power on [solved]
« on: June 23, 2021, 05:24:16 AM »
Hi,

I'm using ATXRaspi R3 for a couple of months now and recently I started to have problems. After I disconnect a power supply from the grid and connect it back, red led on ATXRaspi blinks twice very fast followed by two blinks with about 1 sec apart. When I push momentary button to power up raspberry it starts to boot, but after about 5-6 secs the led on the momentary button starts to fade and raspberry goes off.. Sometimes I'm able to boot my Pi from 10th of 15th try. If it boots green led goes on and shutdown is working as expected. If I keep my momentary button pressed, Pi boots, but as soon as I release it it goes off.
« Last Edit: July 08, 2021, 01:08:55 PM by Felix »

Felix

  • Administrator
  • Hero Member
  • *****
  • Posts: 6605
  • Country: us
    • LowPowerLab
Re: ATXRaspi R3 does not power on
« Reply #1 on: June 23, 2021, 09:34:15 AM »
Sounds like intermittent power loss or SHUTOFF signal is not stable.
This type of fault is sometimes due to wire/connection issues, or not clean solder joints. Ensure the USB or VIN 5V power is a clean and stable one, not delivered by a faulty worn out cable.
Check your soldering. Clean any flux residues. Ensure the wires/connections are not oxidized or loose. Ensure the solder joints are very good. Ensure all the wires to/from Pi are very solid and not loose.

smoove

  • NewMember
  • *
  • Posts: 7
Re: ATXRaspi R3 does not power on
« Reply #2 on: June 30, 2021, 01:50:11 AM »
I will check wiring. I noticed that if the red led blinks twice followed by another two blinks with 1 sec apart after I connect power, it fails to start. Sometimes it blinks three times with 1 sec interval. In such case it always boot fine. Maybe this will give an idea of error? Soldering is OK, but I use original micro-usb raspberry AC adaptor, which is 2A, while my pi is 4th generation. Maybe that could be an issue as well? However, I never noticed low voltage indicator. There could be issue with the wires which go to the GPIO of Pi. Are these important during first few seconds of boot?

Felix

  • Administrator
  • Hero Member
  • *****
  • Posts: 6605
  • Country: us
    • LowPowerLab
Re: ATXRaspi R3 does not power on
« Reply #3 on: June 30, 2021, 09:02:46 AM »
You don't have a higher amp rated AC supply? My guess is the power is too low. Measure the output (and input) with a DMM or ideally with a scope. Then you can see if there are dips in voltage.
Also, if your Pi is a heavy load you'd maybe want to use the DC input or the input power header, with very good quality dupont terminals.

The ATXRaspi R3 has some jumpers which determine the expected type of power button that is connected, and behavior of the shutdown/reset. These reflect in the RED blinks at startup. This is explained in the guide which I am sure you have already checked, so I won't copy paste here.

You can also debug by powering without a load, and to simulate a BOOTOK just jumper the output 5V to the BOOTOK signal after output power is turned ON by ATXRaspi. See if it behaves the same as with the Pi load.

smoove

  • NewMember
  • *
  • Posts: 7
Re: ATXRaspi R3 does not power on
« Reply #4 on: July 01, 2021, 05:08:18 AM »
It seems that I checked everything and the problem persists. First, see the video where you will find the blinking pattern of Shutdown LED after I connect power supply to ATXRaspi: https://streamable.com/09xgu9

Another video show how everything behaves in case of raspberry connected: https://streamable.com/iqb2h6. It boots for about two or three seconds and then everything goes off.

I tried without raspberry as well. ATXRaspi behaves same. After button press the button LED goes off after few seconds. It doesn't matter if I "simulate" BOOTOK or not.

P.S. Now I use 5V 5A DC power supply which should be sufficient.

Felix

  • Administrator
  • Hero Member
  • *****
  • Posts: 6605
  • Country: us
    • LowPowerLab
Re: ATXRaspi R3 does not power on
« Reply #5 on: July 01, 2021, 10:53:25 AM »
The first 2 rapid blinks mean the board expects a latching button. That would imply the LATCHING-BTN jumper is closed. This is described on this guide page.
Looks like you have a momentary (non-latching) button. So ATXRaspi behaves correctly in this case. It's like you press the power button, and since it's non latching, it's like un-pressing it right away asking for an instant shutoff right after power on.

So the question remains - is that latching btn jumper closed? If not, what makes it think it's closed. The latching jumper is an analog input which if reads below 800/1023 it will consider the setting as LATCHING-BTN. Does your latching button have some king of internal pull-down?

Can you try without the button pins connections? And instead just use a tweezer or wire to trigger a POWER-ON on the "POWER BTN" header pins?

smoove

  • NewMember
  • *
  • Posts: 7
Re: ATXRaspi R3 does not power on
« Reply #6 on: July 01, 2021, 11:57:11 AM »
I don't use latching button (I use momentary instead) and the LATCHING-BTN jumper is open. It's strange, but these 2 rapid blinks are always there after I connect power. So what we can conclude is that the board always expecting a latching button.

I made another two videos to make you understand things that I've done. First video again show the story with momentary button. As expected, system goes off after few seconds: https://streamable.com/c7n27p

Just after that without disconnecting the DC power I disconnected a momentary button and connected two open wires to POWER BTN pins. After my first attempt to shorten the wires the process was same as with the momentary button connected - system goes off after few secs. On my second try to shorten the wires, the system actually starts and then goes down. You will see at 32 sec in the video that the power led of Pi goes off for a second and then is rapidly on again. This repeats multiple times so I assume my pi goes on and off in a loop. Here is a video: https://streamable.com/2rlikk. As you will see, the LATCHING-BTN jumper is open.


Felix

  • Administrator
  • Hero Member
  • *****
  • Posts: 6605
  • Country: us
    • LowPowerLab
Re: ATXRaspi R3 does not power on
« Reply #7 on: July 01, 2021, 01:10:44 PM »
The jumper is not visible in the video.
In the startup 3 sets of blinks, the first blink sequence has always been a double-blink and never a single blink?

Can you pull-DOWN the left most pin "SoftBTN" (which you have untouched)?
Can you pull-UP (to 5V input) the second pin which is next to it (this is one of the "POWER BTN" pins that is not grounded).
Use a 1K resistor in both cases.

Assuming your LATCHING-BTN jumper is indeed open (ie left untouched as shipped), this should most definitely force the board to operate correctly with a momentary SPST button/switch that has no internal pull resistors or anything like that.

smoove

  • NewMember
  • *
  • Posts: 7
Re: ATXRaspi R3 does not power on
« Reply #8 on: July 02, 2021, 01:51:43 AM »
In the startup 3 sets of blinks, the first blink sequence was single blink some time ago. I have been using ATXRaspi for about 6 months now and this strange behavior is quite recent. For first few months it worked just fine. And I have been using same momentary button. Then couple of weeks ago I was able to start system from 2nd or 3rd try and it progressively went worse until now when I'm unable to start it at all with momentary button.

The LATCHING-BTN jumper left untouched as it came from manufacturer, so it's open. Actually, I tried to assemble connectors on another ATXRaspi (I had new untouched one). This also behaves same as previous - it shows 2 rapid blinks at power and seems to be expecting a latching button. Can you imagine a scenario that my power adaptor or my raspberry configuration can mix-up things for ATXRaspi microcontroller? I still have few new ATXRaspi switches, so I could experiment.

Regarding pull-up and pull-down I will do that soon and keep you updated.


Felix

  • Administrator
  • Hero Member
  • *****
  • Posts: 6605
  • Country: us
    • LowPowerLab
Re: ATXRaspi R3 does not power on
« Reply #9 on: July 02, 2021, 09:56:06 AM »
It's not impossible that jumper input to the microcontroller somehow got damaged to the point where it always reads a "LOW" and the MCU thinks the jumper is closed. How that happened I don't know since I don't know the history of this board and its use, maybe you have a better idea there. Or some kind of noise or environment condition?
But it certainly is a first time that this type of thing is reported, that I remember - it working and gradually getting worse.
I'm curious what the pull-up/down I mentioned would do. Otherwise a new ATXRaspi wired identically I would expect would work, if it takes another few months to develop the same problem then it's really something strange, especially that there is no known way to reproduce this right away.

smoove

  • NewMember
  • *
  • Posts: 7
Re: ATXRaspi R3 does not power on
« Reply #10 on: July 08, 2021, 11:10:56 AM »
The pull-up, pull-down resistors forced ATX raspi to work with momentary button. Now MCU reads HIGH and works with momentary button as expected.

However, I noticed, that MCU probably gets some signals from the environment (or from the connection of power supply) and then "remembers" that HIGH/LOW state. For example, I took a new ATX Raspi fresh from the box. Once I connected it to the power, it blinks once and is ready to work with momentary button. Then I started to solder the connectors (power, USB etc). After each connector soldered I checked the status of LED by connecting power. Soon I noticed that it started to blink twice. Maybe this is because I connected power, disconnected it and then connected back right away. After my first attempt it blinked once, but after I connected power again it started to blink twice. From then on ATX Raspi stayed in the same "latching" state. So I soldered pull-up/pull-down resistors and ATX Raspi came back to momentary mode. Then I disconnected the resistors and it stayed in momentary mode. So this did some kind of reset to the MCU. Anyway, to avoid switching to latching mode accidentally, I think I will use ATX Raspi with pull-up/pull-down resistors from now on.

Felix

  • Administrator
  • Hero Member
  • *****
  • Posts: 6605
  • Country: us
    • LowPowerLab
Re: ATXRaspi R3 does not power on
« Reply #11 on: July 08, 2021, 01:08:39 PM »
It's very strange that the pull resistors are required in your case.
I will consider if adding these on the PCB in the next revision will be necessary, although internal pullups are used. The datasheet specifies certain ranges for these internal resistors which are not a fixed given value. In any case I am glad you could resolve your issue, I hope we can call this resolved for now.

smoove

  • NewMember
  • *
  • Posts: 7
Re: ATXRaspi R3 does not power on [solved]
« Reply #12 on: July 09, 2021, 01:31:21 AM »
Yes. Thank you Felix, without your prompt responses and honest help I wouldn't be able to solve this.

Felix

  • Administrator
  • Hero Member
  • *****
  • Posts: 6605
  • Country: us
    • LowPowerLab
Re: ATXRaspi R3 does not power on [solved]
« Reply #13 on: July 09, 2021, 09:46:25 AM »
Thank you as well, I appreciate your patience to resolving this and following up.