7640U Not Booting in Standalone Mode

Community Support
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1

Hi all,

Basics:

  • FW13 chassis
  • 7640U (3.18 BIOS), AI 340 (3.05 BIOS) boards
  • Cooler Master standalone case
  • Windows 11
  • RTC Battery installed
  • 65W GaN charge/ 140W battery

I’ve been working through troubleshooting steps with Framework support, but this seems to be a tricky one, so I’m hoping someone else has bumped into this before. The situation is this, I bought a FW13 with a 7640U board and used it for about a year until deciding that I wanted to move that board into the Cooler Master standalone case to replace my ageing HTPC. I ended up ordering a AI 300 board as a replacement for the laptop and installing the 7640U board in the CM case.

Both boards absoluely refuse to boot in the CM case, no matter what I try. They’re both set to standalone mode and have an RTC battery installed.

Most of the troubleshooting has been done on the 7640U so I’ll focus on that. Initially I didn’t set it to standalone mode, so it did the red/blue flashing LEDs. After sticking it back in the laptop chassis and setting it to standalone mode, the red/blue LEDs don’t flash, just the white/green power indicator LEDs on the side of the board with the power input.

The board behaves in two different ways and seems to switch between them at random.

Mode 1: Most of the time, pushing the power button causes the power indicator LEDs on the board to turn off momentarily, the fan to spin for 2-5 seconds, and the ethernet adapter activity lights to flash on once. It seems to need a couple of seconds between power button presses, but it will repeat that pattern as long as you have patience to keep pressing the button.

Mode 2: Infrequent, not easily reproduced. Every now and again after some new troubleshooting steps the board will light the power indicator LEDs when power is connected but pushing the power button doesn’t cause those LEDs to flicker off. The fan usually doesn’t spin, but the CPU and SSD controller get hot (almost painful to the touch) for about 10 seconds and then cool back off. When it’s behaving in this way pushing the power button usually does nothing, but once it’s been through its heating/cooling cycle, the power button will eventually cause the heating cycle to repeat. Sometimes the ethernet adapter activity lights flash twice, sometimes not at all.

At no point has either board given any display output when in the standalone case. Both boards boot and work flawlessly in the FW13 chassis.

I’ve tested the following:

  • I/O modules in most (all?) permutations of the 4 slots (all installed and minimal installed)
  • 3 GaN chargers 45W and 60W
  • 140W battery bank (Ugreen) to rule out under power condition
  • 6+ USB C cables (mostly Anker) in different lenghts
  • Only HDMI out (available monitor/module)
  • Both the 7640U and AI 340 boards (AI 340 only seems to do Mode 1 described above, but I haven’t tested it as much)
  • Turned off secure boot
  • Both boards have Samsung SSDs and RAM on the compatable list
  • Reseting the 7640U using the case open switch 10x press

There’s probably more, but that’s all that comes to mind at the moment. Framework support has run me through troubleshooting and pointed me toward the community post below but I can’t replicate what they describe in step 2. Setting the board to standalone mode should get me to step 5, but it still doesn’t change the behaviour.

https://community.frame.work/t/resolved-mainboard-standalone-w-o-framework-laptop-amd-7040-5-7640u/39301/6

If anyone has any thoughts I’m open to suggestions before I break down and just buy a new chassis, since that seems to make it boot reliably. I’ve been building my own PCs for ever and don’t mind troubleshooting, but I’m entirely out of ideas at this point.

Thanks in advance.

2

Another thing to try would be adding the battery.
I.e. with the mainboard outside the case, also connect the battery and see if it boots.

Also, try plugging in the laptop display to it.

Another way to migrate from laptop to CM case could be:

  1. have it working with laptop display and laptop battery. Set standalone mode in BIOS.
  2. plug in external display and external keyboard / mouse.
  3. boot the sysyem into OS, see the external display working and the external keyboard/mouse working.
  4. power off and laptop and remove laptop keyboard. Add rtc battery.
  5. boot into OS again and see it working on external display.
  6. power off.
  7. remove laptop internal display cable.
  8. boot into OS and see display working.
  9. reboot and enter bios with F2. Repeat a few times until you see the bios screen on external display.
  10. power off, and remove battery connector, but retain rtc battery.
  11. boot up again and check it is all working, and you can see the F2 BIOS on the external display.
  12. remove mainboard from chassis, leaving the RTC battery connected.

In this way, you might determine what else it needs connected before it will boot.

I suspect some bug in the EC firmware or BIOS preventing it from booting.

3

Thanks for the tips!

I forgot to include that I did pop the barttery out of the chassis and plug it into the board to see if that it’s objecting to, but I didn’t think to disconnect the board inside the chassis one connection at a time. I’ll give that a shot this afternoon when I have time and update this thread.

4

Starting with the dissasembly of the AI 340 since that’s what’s currently in the chassis. I’ve bolded a couple of important pionts

  1. Fully assembled - Display output and USB keyboard working.
  2. Set standalone mode - Reboot prompts me to turn off standalone, so it seems to be working.
  3. Remove keyboard - Boots and prompts me to turn off standalone.
  4. Remove audio connectors - Boots and prompts me to turn off standalone.
  5. Remove wifi module - Boots and prompts me to turn off standalone.
  6. Disconnect webcam - Boots and prompts me to turn off standalone.
  7. Disconnect main battery (no RTC battery) - Framework boot splashscreen on first boot attempt, boot not completed. Subsequent boot attempts seem to follow “Mode 2” in my above post.
  8. Reconnect main battery (with RTC Battery) - Boots and prompts me to turn off standalone.
  9. Disconnect main battery (with RTC Battery) - Framework boot splashscreen then black display, fan repeatedly spins for 2 seconds then stops for about 5 seconds (seems to continue indefinately). CPU and ssd are hot.
  10. Reconnect main battery (with RTC Battery) - Boots and prompts me to turn off standalone mode.
  11. Disconnect display, main battery connected - Boots to Windows on external display
  12. Disconnect main battery - Fan repeatedly spins for 2 seconds then stops for about 5 seconds. After sitting like that for about 2-3 minutes the onboard LEDs flashed through a sequence of red, blue, and green (not sure about the order, it happend fairly quickly). Fan no longer spinning, back to power in indicator LED only. No display output, CPU warm.
  13. Left it sit for a couple of minutes and then pressed the power button again. Fan spins for about 15-20 seconds every minute or so. I left it like that for about 5-7 minutes with no changes.
  14. Reconnected main battery (with RTC Battery) - Boots to windows.

At this point it definitely seems that it’s grumpy about not having the main battery connected. I removed the AI 340 board and installed the 7640U

  1. With only the battery and internal display connected - Boots to Windows normally.
  2. Disconnect internal display (with RTC Battery) - No display out, behaving like “Mode 1” in my post above.
  3. Reconnect internal display - Boots to Windows normally.

At this point I realised that I don’t think I’ve ever tried using the 7640U with an external display. Since I couldn’t get an HDMI display signal from the 7640U, I reinstalled the AI 340 board in the chassis. It worked fine with two different HDMI monitors, so apparently the 7640U is a bit touchy. That points to there possibly being 2 problems here.

  1. Both boards refuse to boot without the internal battery being connecte.
  2. Some incompatibility between the HDMI module and the 7640U board.

Any thoughts would be appreciated. I’ll also follow up with Framwork support to see if they have any ideas.

5

Well it seems you have at least diagnosed the problem.
For 1): This is likely an EC firmware bug, so at least FW engineers should be able to reproduce the problem.
For 2): Try connecting the HDMI to a different slot. I don’t think it is supported in every slot. Is the HDMI module provided by FW, or elsewhere?

6

I really appreciate the suggestion, I made more progress today than I have in weeks. Not sure why that didn’t occur to me before :slight_smile:

The HDMI module came straight from FW, so hopefully they can suggest some troubleshooting steps. Display out isn’t supported in slot 2 (left, closest to the user) but I tried all 4 slots just to be sure. I’ll keep working with them and post any updates here.