Dead T9+ Board (Burnt Inductor chip)

[Kenni88]

Hello all

Decided to open the T9+ even though I must have over 100 days warranty, but cant be bothered to send it back.
2 boards are dead.  Each of the dead boards has a burnt 1R5 1784 induction chip.  Im not into electronics, but could someone guide me to a correct chip?  Could i use a different value chip?

Thanks

[cvokey]

I have the same problem with several T9+ the chip is a 1R5 1750 and i cannot seem to find a replacement.

does any one happen to know where to get one or several of these?

Thanks

[BitMaxz]

I have the same problem with several T9+ the chip is a 1R5 1750 and i cannot seem to find a replacement.

does any one happen to know where to get one or several of these?

Thanks

I don't find any website from google who offering for hashboard replacement.

The only thing comes to my mind is to send it back to the manufacturer for warranty or you can try to check this section https://bitcointalk.org/index.php?board=75.0 and look for hashboard sellers or buy 2nd hand/broken t9 that you can use for parts replacement.

[tim-bc]

You would either need to get the authorized purchase account from bitmain after attending training or just get the chip from scrap/spare boards if you have any.

[lightfoot]

Hm. Can you post a pic of the chip and the board? Wonder why it burned.....

[cvokey]

here are some pics of the chip

https://imgur.com/ZxsLbgu
https://imgur.com/eMBNsho
https://imgur.com/raGhbYa
https://imgur.com/2bvVSSZ

[thierry4wd]

Hi, I do not know if I have the right to post a link, but here is one ...

https://fr.aliexpress.com/item/Chip-integrated-forming-inductance-10040-1-5UH-1040-16A-silk-screen-1R5-10-10-4MM/32818992637.html

it is actually a simple inductance ... You have all the detail now!

really simple to replace ...

[lightfoot]

Agreed, that's a simple choke/inductor. The much bigger question is why did it burn out. Hm....

Get some close ups of the transistors next to it please, and check to see if they are shorted source to drain (or across the gate). I'm willing to bet a banana that the high side fet shorted, putting +12 across the string of chips which overloaded the choke.

There's another pair of transistors and choke on the right, so I wonder if there are two power planes, or if these two run 180 degrees out of phase to smooth the load on the one big inductor. Slightly different type of design (doesn't need two low side FET's, interesting) I'd be interested in knowing what kind of transistors/fets they used.

[cvokey]

here are 2 of the opposite side and one of the same side close up

https://imgur.com/a/ak7o9y1

does this look like the same part
just looking for something closer as shipping from aliexpress will take over a month to get here unless i want to pay a huge shippig price.

https://www.mouser.ca/ProductDetail/TDK/SPM10040T-1R5M-HZ?qs=%2fha2pyFaduhzVjKLjKU7bj5ZS53OWTldbSKi7EbqWOcjLWO85Y2KxyWYO2QDjpqB

as for testing i am sorry but i am not really much of a board level tech so i don't really know how. i just saw broken part and was hoping that replacing that might fix it.  as for everywhere else around the inductor i don't see any kind of damage on any of the boards just that part.

[BitMaxz]

You need to remove the burned choke/inductor first and check the 2 terminal if shorted or not using multi-tester.
To remove the choke/inductor you must have a hot air rework station. If in case it shorted there are another broken or damaged parts that may cause to inductor/choke become burned.

Do you have DC Digital Power Supply? Because you can use it for tracing if which part from the hashing board is causing the burned inductor/choke.

[lightfoot]

If he's just pulling the choke he can get away with a good iron and some chip-quik (the cheap bastard solution to SMD rework). That pulls down the melting temp of the solder to something that is low enough you can pull with an iron. Handy crud but can't easily get under a TO type case on a transistor.

I'd say check the resistance on the FETs by checking the resistance from +12 on the connector to the transistor side of the choke. If it's low resistance then one of the FETs has shorted. Then you get your preheater (God in a box), warm up the board to 150c or so, put some Kesterel liquid flux on the FET, pull it with 380c hot air, then clean everyting up, tin with good old rosin core tin/lead solder, then flux and put the new FETs on.

Result, happy board.


I'm guessing the PIC chip is the waveform generator/general purpose processor, which then drives the 3420 as a dual POWER Fet driver, which then drives the gates for the um... FETs. You need power to drive the gates because they are running at a high frequency, and each off needs power to be done quickly in order to keep both FETs from being open.

Still think the high side FET shorted closed, which would mean the +12 supply would have gone straight to the chips, which would have blown the weakest component being the choke. Did you have a big honking power supply plugged to the board, smaller supplies would probably have crowbared first.

Interesting stuff, keeps my brain working.

Edit: If my posts are not technical enough, pls let me know and I'll fiddle with something else.

[Kenni88]

I had 2 boards fail.  Both boards had the 1R5 inductor burnt at the same location.  As each board has 2 x 1R5 inductors, I desoldered the burnt inductor from one board and replaced it with the good one.  So I made a good board out of the 2 bad boards.  It works, so probably just a crap batch of inductors.

[cvokey]

I had 2 boards fail.  Both boards had the 1R5 inductor burnt at the same location.  As each board has 2 x 1R5 inductors, I desoldered the burnt inductor from one board and replaced it with the good one.  So I made a good board out of the 2 bad boards.  It works, so probably just a crap batch of inductors.

that is what i was thinking of trying before i ordered anything

[Cliffman]

So did you end up buying any new chips for this? I have the same problem and am looking to get some replacement 1R5 chips.

Thanks