BM1366 ASICs not responding, overheating issues

Hey all. I could really use some help here. I designed a board with 4 BM1366 ASICs, based on the Bitaxe design. Been trying to get them running for days now but no communication. The controller sends data, but nothing's coming back. I noticed the current spikes as the chips warm up. In the beginning, I had no heatsink or just a basic one. Could overheating have damaged them? I'm powering the ASICs with 2.4V.

If you got them running without a heatsink, they probably fried in seconds. 12 watts in a small package heats up fast. Most semiconductors can go up to 125C but fail around 150C. Had a BM1397 before, they hit 85C almost instantly without cooling. Your ASICs likely got wrecked.

Isn’t 2.4V too high for these chips? Why not start with a safer lower voltage like 0.8V and then gradually increase it based on their temp? And seriously, without a heatsink or fan, how are you cooling them? Sounds like you cooked them.

Appreciate the feedback. I think 2.4V should be okay. I have two chips in series, so each gets its 1.2V. But yeah, I’m seeing some voltage distribution issues. As for cooling, I thought they’d just warm up during idle, but I guess I was wrong.

Can you share a schematic? It’s hard to troubleshoot without visuals.

The first page shows the wiring and modules. Just a heads up, currently testing with only two ASICs assembled. The level converter and the other two chips are not on yet. I'm feeding VDD1 1.2V directly from the power module.

Quick note: I got my BM1366AL chips from NBTC. Could that be an issue? I’ve seen others on Discord having detection problems with this AL version on Bitaxe Hex. Any official word on that?

Honestly, I don’t know much about Bitaxe’s software. It could be that it doesn’t support the AL variant. It might be looking for a specific chip version ID. Best to reach out to the Bitaxe devs for help. By the way, I noticed a few things in your schematic: 1. Pins 8 and 11 on U6 should not float, you should tie them down with a resistor. 2. The enable pin for X1 floating isn’t a good idea either.

Thanks for checking my schematics. I made a few changes: 1. Supplied VDDIO_18 with 1.2V. 2. Checked that the oscillator works with 1.2V. 3. Generated 0.8V from the 1.2V. So when the power's off, VDDIO is off too. I think I’m following the specs, but still no response from the ASICs. I’m open to any suggestions.

If you’re sure the hardware is good and you’ve checked for assembly mistakes, it’s gotta be a software issue. Good luck! Not my thing though, I'd suggest talking to the Bitaxe software team for guidance.

I didn’t check your schematics, but you can use Vcore for 1.2V to save costs. I switched all my miners to run at 1.2V. And you can create 0.8V with a simple resistor divider. The ASIC doesn’t pull much on that line. For testing, try tying the first ASIC’s BI to ground and RI to 1.2V so it’ll respond to the right commands.

Guess what? I finally detected a chip on the board! FINALLY:-). Turns out the problem was a bad solder joint. I reballed the chip and then soldered it onto the PCB. Now there’s communication! But the current is still low, and it’s not really hashing. But hey, at least we’re talking to the ASIC now. Thanks for all the help!

Awesome news! Good luck getting it to hash properly. Just a tip from my experience with BM1397: they’re super sensitive to core voltage changes. Like, 50mV can be the difference between it working or not. Start with a clock rate around 400MHz and tweak the core voltage.