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 Post subject: MX300 PCB repair
PostPosted: December 8th, 2021, 6:38 
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Joined: December 8th, 2021, 5:24
Posts: 2
Location: California
Hi everyone. I'm new to the site, but have found it very helpful in fixing the other drives that suffered the problem I will soon describe, and in identifying components of this MX300 that I'm still having problems with. I'm hopeful that you'll be as understanding and as helpful as I've seen so far, but please feel free to redirect me if I have missed something in my search and this has already been covered before!

I have a Crucial MX300 2.5" form factor, 275GB, with model #: CT275MX300SSD1 (if you need any other numbers, let me know!).
I suspected I had an underperforming PSU, and in the process of being a good debugger and isolating the problem, I changed out /only/ the PSU and not the cables (several of you know where this is headed), and promptly fried my hard drives' components because there is apparently no standard pinouts for PSUs, and I gave my drives 12V to their 5V rails. Fortunately my Samsung SSD had protection and survived unscathed (I think), and my HDDs only had their TVS diodes shorted for an easy fix. The MX300 was another story entirely, with at least 2 components letting the smoke out. I am shocked there was no protection closer to the supply rails, but I'm no circuit designer, so /shrug.

There were two clearly blown ICs, which due to similar layouts and the photos revealing letters that I'd previously been unable to see, and thanks to this lovely post, I determined were buck converters (TLV62080-ish). I figure, "hey, I can try to fix that." Digikey's out of them, but "maybe I can just hook up a voltage source or two once I figure out what they were set to." Unfortunately, without knowledge of the circuit, I'm not sure if there's anything else wrong or things that I might expect might be wrong, or whether or not what I'm reading from my multimeter makes sense. So I'm hoping to get some clarity on this circuit from you experts.

Here are my main issues so far:
- I don't know the /intended/ local circuit around the chips. This prevents me from calculating what the output voltage would be as configured by the resistors.
>>> Right now it appears the resistors connected to the feedback pin are just parallel connected to ground which seems weird, but I noticed that the larger capacitor seems to be shorted (oh, now that I'm thinking about it, maybe that's an inductor? I don't suppose there would be any reason for the cap to fail, and that would explain the 0 Ohm reading... Does anyone know a good way to tell the difference with a basic multimeter?)
- The resistance readings I'm getting on the resistors is different for each of the regulators, but I don't know if that's due to the damage just changing the circuit config or not.

After running into these roadblocks I requested some quotes from some companies around this SF Bay Area, and promptly concluded that I could not afford the $650+ they were expecting it to cost, so I'm hoping to solve this problem myself, even if I have to pay another student (hopefully way less) who has steadier hands for the fine soldering.

So question #1: Does anyone know what each of the chips are programmed to output?
Question #2: Does anyone know of other components that I should check that they would expect to be damaged?
Question #3: Assuming I can get the parameters of the converters and their circuits, if I can't get my hands on any more of those buck converters (apparently there's a 38 week lead time on digikey...), I could try just hooking up some voltage supplies. But I don't know whether or not using an external voltage supply would damage anything. Would it?
Question #4: If it would be "safer" in terms of data stability to just transfer over to a replacement PCB (versus possibly getting the voltage wrong or missing another problem with the circuit), what components would I have to transfer? I know for HDDs you need to pair the disks with the "BIOS chip" when replacing a board; is there a similar chip that handles addressing for SSDs (and anything else)?

(As a tangential aside, now that I've transfered the data off of them, I'd like to keep using the other affected HDDs for other purposes, but with new PCBs. However, I don't want to transfer their BIOS chips to the replacement boards. If I just put brand new PCBs in, I should be able to just format the drive and use it normally assuming I don't need the old data on them anymore, right?)

I've attached photos (and realized the pixel 5a lens is really crap with macro apparently), and am happy to take more photos, provide more information, or take any readings you want! Just let me know what I can do to help you help me :)
Thanks so much!


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 Post subject: Re: MX300 PCB repair
PostPosted: December 8th, 2021, 14:14 
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Joined: November 7th, 2020, 5:31
Posts: 1084
Location: The_UK
Why not grab a couple of donor drives from ebay, they're cheap as chip over here and it will give you all the spare parts you need. Wouldn't like to comment on the recovery chances.

If you want to continue to use the other drives replace the protection you have removed (TVS & fuses) if they're working there's no need to replace the PCB's.

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 Post subject: Re: MX300 PCB repair
PostPosted: December 8th, 2021, 14:30 
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Joined: September 8th, 2009, 18:21
Posts: 15463
Location: Australia
I would remove the two obviously damaged DC-DC converters and measure the resistance between the inductor and ground. This will tell you if the overvoltage has punched through the chip and damaged the load.

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 Post subject: Re: MX300 PCB repair
PostPosted: December 22nd, 2021, 3:25 
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Joined: December 8th, 2021, 5:24
Posts: 2
Location: California
Very late update; sorry about that! Got very depressed with my results and lost motivation. Fortunately, I DID find that backup I thought I made (phew), but it's a year and a half old. I would still like to recover this drive's data if possible.

I removed the worst regular (top left) and after some cleanup, I've learned that it took ~2.3 pads with it (the Vin, SW, and part of the PG; also part of the thermal pad). It's possible I contributed slightly to this (did I mention I have a tremor and HATE SMD soldering?), but after reviewing the photo I feel like most of this damage was already done. It does at least explain why the capacitors seemed shorted and the resistors didn't seem like they were in the correct feedback configuration: there's a low-resistance short between 5V and GND. I should've checked this initially, but I think I was very tired and not thinking straight.

Basically I believe the Vin input and SW output have both shorted to ground through the board, or through some surface connection I can't make out due to the brown/black mess that remains (alcohol didn't work, and but I'm afraid acetone might damage something--any thoughts would be welcomed). As a result, the inductor resistance that Mr. Zabkar (orz orz) recommended reading is 0 quickly rising to 4 Ohms reading from both sides of it. But due to my lack of knowledge, I don't see exactly how this reading would indicate damage to the load. Clarification would be appreciated! (orz again)


I certainly feel far less confident in my ability to repair this situation, and have 0 experience in reattaching traces to pads. I fear transplant might be the best option (unless jtagging is surprisingly accessible?), but that leads to a whole lot of other mess of BGA resoldering and some important questions:
1) I know the 2 main memory chips would need to be transferred, but what other components also need to join them? (e.g., BIOS chip in HDD transplants)
2) Is there any reason to think it would not be reasonable for a person with a BGA jig + balls, hot plate + heat gun, wide iron, wick, and flux to attempt this job?
3) If I paid someone to do the transplant (I don't think my hands have it in them), how much do you think a reasonable price would be? (I understand if you can't/don't want to answer this. If you'd prefer a different question, see 3a below)
3a) The lowest price I got from Secure Data Recovery was $400. Presuming I /do/ want to recover the data, do you think it would end up being cheaper to go with them or finding someone to do the transplant?



(Question 5, related to the other HDDs and basically my previous aside, with a clarification: If I don't need the data off an old drive, would there be any /problems/ just putting a new PCB on it and using it? [Disregarding what I /could/ do--I'm just wondering if it works, since it would be way easier for me])
Thank you all again!


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 Post subject: Re: MX300 PCB repair
PostPosted: December 22nd, 2021, 6:54 
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Joined: November 7th, 2020, 5:31
Posts: 1084
Location: The_UK
iikamrii wrote:
I can't make out due to the brown/black mess that remains (alcohol didn't work, and but I'm afraid acetone might damage something--any thoughts would be welcomed).
Depends on what the mess is, Slap some flux on and heat it up a bit and clean off with IPA. If it's charring then you'll need to carefully scrape it away with a knife. Trace repair is delicate but not complicated - Most of us do it under a scope :wink: if you're not happy with trace work then bga reballing is going to give you nightmares.

1. You don't know what IC have been overvolted they could all be dead.
2. Moving unique IC's would be a last resort but anyone with BGA experience is technically capable.
3. I wouldn't be paying anyone to move things blindly - if you're contemplating that, take it to a real DR lab.
3a. Data recovery isn't cheap for a reason, you don't have to be concerned about a transplant working, either the data is recovered or it isn't. The price you have been given is a little under what would be charged (assuming it isn't fried) if it showed up here for recovery.
5. The chances of swapping a PCB and the drive working are very very slim. You'd need to move the roms. If it's just protection that's been triggered it's easier to fix the original PCB. Post PCB pictures and someone will point you in the right direction.

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https://www.usbrecovery.co.uk/


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