Thanks Mikeywith, I saw that too and I think not going over this and avoiding this arrangement is the plan and wait for the AD's to become available. Wndsnb, I removed one of the chips and two of the smallest resistors (they had a black top with white core) blew off - one was labeled R2020 and the one next to it was a R2016. These are right next to the chip. I would assume that the R2016 is 201MΩ ± 1% and the R2020 is 202Ω ± 1%. Do you have any direction on how to find these on Mouser? Or do you have another source? Oh, and apparently I don't have the micro tweezers for this job what are you using for these things?

Edit: Looked on ZuesBTC to see if I could narrow it down but didn't find anyhting. Also nearby noticed C86 and C84 (ceramic capacitors?) were off so if you have leads on these types it would be appreciated.

Thanks again.

Thanks for the temp. confirmation. Ha. That PIC chip. It amazes me how many things can go wrong with these and you really have to double-check your work. 

The higher temp. approach is interesting and since the factory solder is so weak I think of a higher temp Sn/Ag solder paste to improve strength. At a cost.

I was able to take a closer look at the PIC chip under microscope and seems that when the temperature sensor was replaced and reflowed it dislodged half of the pads on one side. So that half is just floating in the air. I'm gonna take a wild guess and say that is where no PIC detected comes in.

For the other board, the chip with the fallen heat sink is going to be replaced but I am seeing conflicting information on what solder paste to use for chip replacement. I'm seeing some use 180deg. paste?

For the heatsink replacement: Amtech 138deg. low temp. SN42/Bi57.6/Ag0.4 Lead-free. And the Chip Quik you reccomended.
 
Solder wire: Kester "44" SN96/AG03/Cu.5 Lead-free.

For the chips: I'm confused here on what to use.

Could you recommend the best formula of paste solder and temp. for replacing chips? Do you know what temp. paste it is from the factory?

Would really appreciate your opinion on what solder I'm currently using and a direction for the chip paste.  

Thanks again. 

Mopar's explanation of purpose sums it up quite well but instead of 6", this one uses 8" capturing hash and power exhaust.

I see, the copper delaminated from one of the chips with the dislodged heat sink and will have to be replaced. I've concluded this copper film and the solder is well below sub-par as you suggest after working with it. Thank you for the insight/method of reflowing the chip with the factory solder on the chip with the chisel tip. I wonder if it's also sometimes necessary to add a little solder paste to replace the solder lost on the bottom of the dislodged heat sink. It would be great to see a picture of your perfect reflow on a chip for reference.


I do have 3 dissimilar questions I hope you could shed some light on:

1. If not running Bitmain stock firmware would you ever need the EEPROM flashing option that ARC offers?

2. I know you touched one this earlier but does the Bitmain repair center detect other issues like bad PIC chips and temp sensor errors? To what level does ARC do this?

3. After taking the bad chip off I noticed on one of ARC's videos that they didn't use a tin and new solder paste to put the new chip in. (that I sometimes see in videos). They added some flux and re-heated the old solder there?

https://www.youtube.com/watch?v=SE-YJRTZezk

Edit: If I go with ARC I will ask them about the editing of those EEPROM values. So it might be a good option to add. 

It's such a great set up and I like the new addition of the desktop DMM to save you a few minutes here and there. One more unit and you might have to hire a real estate agent. Nice catch on IOT. They seem to be the go-to with good communication and delivery. Not surprisingly, they said prices will be going up so I grabbed a handful of AI's. The Hakko's do the job at a reasonable price (using an FX888) until I can find a used JBC Nano or desoldering station. I did pick up a used Zeiss SM and used JBC hot air station recently.

Thank you for the clear explanation on the copper. It's saved me a lot of future headaches and seems to be the rule of thumb that if a heat sink does come off it'd be best practice to replace the chip because you'll have to wick the old solder bumps off and the copper will come with it.  Adhesive just isn't a good option long term. The more I think about chip swapping and from your approach, the worse it sounds vs. just replacing it with a new $8 chip.

Thanks again for sharing your experiences as a lot of us start to navigate this and sharing your incredible station. It's super helpful.     

Wndsnb, I wanted to circle back on this because I was reading one of your replies in an old thread about repairs on the S17. My question is if the copper film is completely off (lets say from a heatsink coming off) what is the reason you can't solder it back onto the copper-less chip? Is it from the degraded thermal transfer? Also, since as of today chips seem to have disappeared from Aliexpress (I did get some several weeks ago) - What is your procedure for taking a chip from a dead board and implanting it on the working board - keeping this copper film in mind. Also, as an update, the equipment is slowly coming together. I can't help but think that self-repair will be the norm for these machines. You're light years ahead of this. Still haven't found any info on chip bm1397 chip naming convention differences.

You're right, not any info about these variants online.

I did order from the CN888 store, they were responsive to why it was cancelled (said it got lost) but seemed off. Might give them another go since it looks like you have recently been successful or the IOT store. ZuesBTC is was the plan B and wanted to get some feedback on them before going in that direction, so thank you for that mikeywith, and the cannibalization of other boards approach.   Surgical loupes seem like a good idea but this PIC chip work and booster might need the microscope to make sure contacts aren't bridged - if they are, be able to correct them properly.  What miner do the AI chips go to? Just looked at the IOT store and just got more confused. This 53 pro came with AD's. They have AH, AI, and AG, is one better than the other?

All the hardware besides ASIC chips from AliExpress arrived - the shipment was "canceled" by them. Maybe they didn't actually have them in stock so I just asked for a refund and didn't ask any questions - on the search to find a reliable source for BM1397AD's. On a whim, I took the boards to a large electronic repair place locally and they wouldn't touch them. wndsnb, I was circling back and taking a look at your setup. Are you using a stereoscope or digital? Looking around Ebay and have come across some Nikons and Zeiss Stemi 2000's. Taking a step back from there and thinking about budget, is there something that will decently get the job done for these smaller chips that you looked at?

I was expecting at least close to $50 for tips. This is welcome on the wallet. Circling back in regards to the PIC chip, when preparing to take the PIC chip off of the board should I use the PIC IT to take that PIC information off first or could I just as well use the 1 working board's PIC information later when the chip is installed on this non-working board?

Awesome to hear it passes the test and what's great is it's about half the price of others. Did you buy any additional tips or have any go-to's for the job? Still waiting on all the board hardware to arrive. Shipping has been really affected lately and/or inventories. 

Thanks for the lead on the power and the glimpse of a mad scientist's workbench. I have yet to see a clean workbench, ever. As it should be. Great equipment setup. It's hard not to overlook, I have a Hakko myself - it's such a great design. Agreed, I think Vnish offers the path of least resistance when attempting to mix and match. Perhaps Marc from Asic.to could confirm this one day or Vnish himself because this is what I would assume a lot of x17 series miners are up against. Hopefully, ARC implements your suggestion and it's not "extra"

Just took an unnecessary dive into oscillators but I think MM Fluke MM will do just fine and I'd like to keep it portable for multiuse. The portable digital oscillators on Amazon are temping for a cheap price. Micsigs are nice but just out of budget. For jigs its looking like the ARC with a good point about monitoring chip hash in Vnish. Do you recommend adding the board testing and EEPROM options with the ARC and what lab PSU are you using? I watched their video and looks like they just clipped power onto the board.

Invaluable information wndsnb. It's a great start and this thread has become a great resource.  I ordered all the parts (and a little bit more for back ups) you listed including chips for the 53 pro boards along with a stencil jig for the chips. Have some old electronic stuff to practice on following your tips once product research is complete over the weekend. After some other research into the Bitman test jig and the Asic Repair Center Jig, I'm not sure which one to purchase because it seems the Bitmain jig has all the more comprehensive information and slower but the ARC is faster and more user friendly where you don't have to do a lot of deep diving and interpretation, has a board tester option and EEPROM flash as options as well. Do you use lead or lead-free solder paste and have any best recommendations? Also, I need to look at a new DMM or oscilloscope - is one preferred over the other for this specific application and perhaps a specific one to look at?

Promising to hear there is some real success mixing boards under Vnish. I think the Asic Repair Center test jig also has the ability to work with the EEPROM...or just EEPROM flashing.

Along with what mikeywith has described in this thread I spoke to a knowledgeable person in mining on TG they say if you run Vnish, interchangeability between boards (50/53/56) shouldn't be an issue. I have my doubts, so I'd recommend buying a PicKit just in case you do find a pro board.

Super happy they are working for you Mopar. Would love to see the pics as a proof of concept at scale. What material did you decide to use?

It looks like I'll be referencing this post for a while so thank you again for this information. Something I know you have experienced with periods of trial and error in your own experiments/research/documentation. After reading your feedback on the adhesive I just threw it in the fridge for emergencies....down the rabbit hole this goes. I actually took a visit to our electrical dept. today and they are using Pace units for desoldering and surface mount work. They said the PIC work could get tricky because each one of the PIC prongs will have to be carefully soldered. Ordered the PIC chip anyways. With some of their recommendations and a little research, it's between Weller WT's (for the tweezer compatibility) + the Hot Air WTHA1 or Pace ST115 with Sodr-X-Tractor. Looking at these numbers maybe take it to a professional with the right tools locally with hardware provided from your list. I will be picking up one of the test jigs soon for diagnosis purposes and got a pickit just in case by a miracle I come across a working 53 pro board.   

https://www.weller-tools.com/professional/USA/us/Professional/Product+lines/WT+Line/Soldering+stations+and+sets/WT2M

https://www.weller-tools.com/professional/USA/us/Professional/Product+lines/WT+Line/Soldering+stations+and+sets/WTHA1

or

https://paceworldwide.com/st115-digital-desoldering-station-sx-100-sodr-x-tractor

I agree, Just to assume that if I do successfully replace the PIC the booster circuit and possible regulators would be next and without digging into that as of now, it could be a non-starter and something that just can't be replaced at a hobbyist level. It sounds like you have had a similar experience with this particular repair on one of your boards so I'm super appreciative of your knowledge and help in putting this into perspective.

A few questions about potentially gearing up for this. It's been a while since I hot-air soldered. What is good out there now? Are there better alternatives, all in one unit, brand to stick to? I see myself doing this in the future so I'd like to prepared. Do you have any recommendations and what tips have worked best for you specifically for the PIC?

Off subject, I am replacing remounting the heat sink on board 3 and ordered a thermal epoxy from Atom Adhesives which are direct replacements for the now discontinued Arctic Silver:

AA-DUCT 902 Silver Epoxy Adhesive, Electrically Conductive, Room Temp Curing
AA-BOND 2153 Thermally Conductive, Electrically Insulating Compound, 2 Part, Thixtropic

I bought both after talking to them directly. Which one of these would you recommend using? Or do you solder yours back on?  

A lot to think about so thanks for the direction here.