Re: Official FutureBit Apollo LTC Image and Support thread

I have a new Apollo. It works great for a few days then one of two things happen.
1. The fan stops completely and start smelling. I have to unplug and plug back in. Glad I?m around when that has happened because I fear it was heating up.
2. Fan speed jumps to full speed. Can?t log in to reboot. Have to unplug etc.
These happen regularly.
Glad I?ve been around in each case. Thoughts?

What mode are you running the miner in?

This is probably related to the MCU lockup issue we know about that can happen in a rare occasion. It should be fixed in the next update we are releasing soon.

I've just had number 1 happen for the first time in several weeks. Luckily happened to check on the Apollo, fan was off, very hot indeed (painful to the touch). Switched off and on again, front light wouldn't come back on (no boot?), left overnight and is fine this morning. Obviously did overheat significantly. Is this the MCU lockup?

(I'm running on Eco, everything auto, on a 200W Dell PSU brick)

Sounds like it. Probably will cut out some features for the next release to just get some bug fixes out quickly by the end of this week and hopefully resolve this.

Since the heatsink so so efficient even with no fan spinning the PCB does not get hot enough to kick in the passive protections and shutdown the regulator...while its very hot to the touch (near boiling temps) its still not hot enough to damage anything, so dont worry if it does happen to anyone else, just shut it down and wait 20-30 min for it to cool down and restart.

Another reason why we need Minimum Fan speed to be adjustable in Auto Fan mode.

That's not really going to help in a lockup scenario. There's a process running on the MCU that's essentially constantly telling the fan to keep spinning. If that process or the MCU gets stuck then the fan simply stops spinning due to lack of instructions what to do. Without adding any new hardware, the only solution is to fix all software bugs and harden that fan controller process to stay running no matter what.

Solving that with a hardware addon (=hack) could be something like adding the cheapest Arduino (or similar) in between the MCU and the fan. That extra chip would then keep repeating the last fan setting received from the MCU and have a delayed failsafe if no new instructions are received within some defined time.

Either way it will get resolved in the next update. Tweaks to the base system should prevent the lockup altogether, and I also enabled the hardware watchdog that's present on the MCU and kept alive by the hardware monitor process. If something happens to this process it will auto-reboot the MCU. This should cover all cases.

There is another semi-hardware solution I can implement that will force the internal pullup on the fan controller high during boot, but this is not very consumer friendly since the fan will startup running full speed for a while until the hardware monitor kicks in (this will force the fan full speed if something shits on the MCU)...i might actually configure this during runtime instead and this will add another layer of protection and the fan will only be full speed for about 5 seconds during boot.