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Topic: NBTC? (Read 104 times)

legendary
Activity: 3374
Merit: 1859
Curmudgeonly hardware guy
March 01, 2022, 01:11:26 PM
#5
Those heatsinks look like a great way to destroy a hashboard or power supply.

Bitmain's individual chipsinks are held to the chips using a low-temp-process solder, probably something bismuth that melts around 140C. That's why so many people have problems with them falling off. In order to support solder, the top surface of the ASIC is copper plating pretty much right over top of the silicon die, which gives absolutely phenomenal heat transfer characteristics. However, the copper plating is internally connnected to ground. One of the failure modes of a hashboard is a heatsink gets loosened then drops to short between the chip and a heatsink from an adjacent row, which operates at a different voltage potential because each "domain", that is to say each row of chips, is put in series.

So unless you're 100% certain that the thermal compound you're using is non-conductive and you're 100% certain that your coverage won't thin out such that you're 100% certain there's no contact between heatsink metal and chip plating metal - and you're 100% certain the screws that are mating into a nut soldered to local ground planes also aren't contacting the heatsink metal - I honestly don't see how this heatsink solution won't be a disaster.
newbie
Activity: 27
Merit: 0
March 01, 2022, 11:36:31 AM
#4
That offer is pretty expensive I don't know if someone will take that offer just to fix or replace the heatsink.

Actually, you don't need to hire Bitmain or someone to reattach the heatsink back to its position you can do it with your self you just need to buy a thermal adhesive to put them back to the hashboard.

Considering it because Bitmain wont fix a board of mine because "one has too many heatsinks fallen off". Any updated thermal adhesive I should use as I will attempt to fix it once its returned to me. I've seen the arctic thermal adhesive suggested but seems to be discontinued on amazon.

$300 shipped to the US is very expensive.
That is almost what it would cost to have a CNC place do it here.
Yes I know you would need to design it, and create the CAD drawings and so on. But still that is US cost not China cost.

-Dave

Interesting.. I might poke around with a solution. If I'm designing it then the design can probably done without having to tin anchor point on the board.
legendary
Activity: 3500
Merit: 6320
Crypto Swap Exchange
March 01, 2022, 06:52:52 AM
#3
$300 shipped to the US is very expensive.
That is almost what it would cost to have a CNC place do it here.
Yes I know you would need to design it, and create the CAD drawings and so on. But still that is US cost not China cost.

-Dave
legendary
Activity: 3374
Merit: 3095
Playbet.io - Crypto Casino and Sportsbook
March 01, 2022, 06:37:44 AM
#2
That offer is pretty expensive I don't know if someone will take that offer just to fix or replace the heatsink.

Actually, you don't need to hire Bitmain or someone to reattach the heatsink back to its position you can do it with your self you just need to buy a thermal adhesive to put them back to the hashboard.
newbie
Activity: 27
Merit: 0
March 01, 2022, 12:25:17 AM
#1

I can across these heat sinks anyone used used them? worth it? Seems like a hell of way to fix the failure rate of the 17 series heat sinks.

https://www.aliexpress.com/item/1005002983783228.html?spm=a2g0o.store_pc_home.productList_6000660073989.subject_2

https://www.youtube.com/watch?v=SCMkRL7j6pU

Who would be able to offer doing the labor? I would love to do at least 1 board in my S17, as Bitmain said they wouldnt fix my 1 board with 5 heat sinks that got removed.
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