Possibly missing SMD resistor on X210 board

[yitzhaq]

Hey,

So TL;DR: Can anyone with access to an X210 board please check component R480 (near the BIOS chip)? Is there an SMD resistor there, and if so, do you know (or are you able to find out) what the value of it is? Or, although I guess quite unlikely, does anyone have to a schematic for the board?



Background:
I'm finally getting around to try to de-brick the X210 Frankenpad previously discussed in this thread: https://forum.thinkpads.com/viewtopic.php?t=131806 (many thanks again to everyone who provided tips, pointers and help). I had one successful go at flashing the BIOS chip using a CH341A USB flasher with the cheapo clip that came in the kit, got cocky as I now figured I had a way to de-brick it when things go south, and proceeded to brick it all over again on another failed coreboot build. Yes, I (now) know.
After this, I wasn't so lucky.. Cue hours of cursing and struggling with the crap clip (which had long since lost whatever grip it once had), until finally succumbing to good advice, and getting hold of a Pomona 5250.

I fear by this stage it was already too late, however, as even with a good clip with a firm grip, I had zero success completing a flash. Thus I have now ended up shipping just the board to an external BIOS wiz abroad, to have the chip replaced with a socket, enabling easy replacement of bricked chips. So far so good.

During this operation, however, he discovered that component R480 seemed to be missing an SMD resistor. At this point I can't say for sure whether I managed to accidentally knock it off during my struggles with the cheapo clip, or if it was missing when I got it, though the former is starting to seem increasingly more likely (inspection under a microscope seems to suggest there has indeed been a resistor there at some point). Assuming a resistor is meant to be there, neither I nor he knows what its value should be. It has been theorized it should be the same as the one next to it (which is (still) present), in which case he can probably figure it out by removing it, reading its value, and replacing it, and putting an identical one in the missing R480 slot. However I'd rather avoid this (essentially guesswork) if at all possible.

The laptop was bought second hand off of eBay, from someone who is said to have bought it from forum member @lulujyc (who I also understand assembled it). It's said to be a "X210 Pre-Production Machine Board ID: 13 (out of 15 eng sample boards in total)" if that makes any difference. I got mine three years ago - I dunno how long the previous owner had it for.

Disclaimer: I don't really know squat about electronics, but am quite happy to act as a go-between :)

Hugely appreciate any help anyone is able to offer on this - many thanks in advance!

[flyingfishfinger]

Yeah, I can take a look for you. Give me a day or two!

R

[bcn]

I looked and probably don't have the same board. Can't remember what gen this is but its an x210 i5. Has both there.

[L29Ah]

I'm too lazy to disassemble my precious X210 and measure it for free, but according to datasheet and your crappy photos it's likely just a pullup for WP# of the SPI flash, so whatever under 1MOhm can be plugged and work. Or ignored altogether if you don't need the flash chip written by the X210.

[yitzhaq]

I'm too lazy to disassemble my precious X210 and measure it for free, but according to datasheet and your crappy photos it's likely just a pullup for WP# of the SPI flash, so whatever under 1MOhm can be plugged and work. Or ignored altogether if you don't need the flash chip written by the X210.

Heh, I was actually gonna say that I'd be willing to sponsor anyone willing to go to the trouble of checking this for me. Is that something you'd consider, for a reasonable donation over PayPal or something?

If not, it does sound as though you know what you're talking about, so I'm inclined to trust what you're saying :) Many thanks for the input! But if you do have access to a datasheet, is that something you would be able to share, just in case?

Thanks again, and thanks also to @bcn for the photo!

[L29Ah]

Heh, I was actually gonna say that I'd be willing to sponsor anyone willing to go to the trouble of checking this for me. Is that something you'd consider, for a reasonable donation over PayPal or something?

If not, it does sound as though you know what you're talking about, so I'm inclined to trust what you're saying Many thanks for the input! But if you do have access to a datasheet, is that something you would be able to share, just in case?

Thanks again, and thanks also to @bcn for the photo!

0.0008 ₿ to bc1qkjqf7uckh06zq67p9gl76ps4d6gzxka7q2uf5e will do.

The datasheet i used for the flash chip on my X210 board (MX25L6408E, 3V, 64Mb, v1.4.pdf): https://tinystash.undef.im/il/3yBGHfQwR ... UuodEs.pdf

[yitzhaq]

0.0008 ₿ to bc1qkjqf7uckh06zq67p9gl76ps4d6gzxka7q2uf5e will do.

Done, I rounded it up to an even 0.001, thanks for the effort! Looking forward to having a definitive answer to this - it's precious to me as well.

The datasheet i used for the flash chip on my X210 board (MX25L6408E, 3V, 64Mb, v1.4.pdf): https://tinystash.undef.im/il/3yBGHfQwR ... UuodEs.pdf

Thanks for this also, I'll make sure to pass it along.

[L29Ah]

So TL;DR: Can anyone with access to an X210 board please check component R480 (near the BIOS chip)?

My mobo seems to have the same layout as bcn's. R480 is measured to have 10kOhm. Just in case it's renamed, I've verified that it connects pin 3 (WP#) to pin 8 of the flash chip. Also, R488 is 28Ohm and connects pin 3 to something else, likely the EC.

[yitzhaq]

So TL;DR: Can anyone with access to an X210 board please check component R480 (near the BIOS chip)?

My mobo seems to have the same layout as bcn's. R480 is measured to have 10kOhm. Just in case it's renamed, I've verified that it connects pin 3 (WP#) to pin 8 of the flash chip. Also, R488 is 28Ohm and connects pin 3 to something else, likely the EC.

Many thanks for checking. I have passed this on, and upon testing, it seems R488 on my board is also busted, as it measures infinity. So I guess that will have to be replaced as well.

Given that you both have the other layout, and my board was claimed to be a development board, I guess the chances of finding someone with the same layout as mine are slim..? If @flyingfishfinger was able to check the layout of his board as well, I suspect he would find the same as both of you (though confirmation would be great if possible, of course).

So, based on my still rather limited understanding of electronics, it seems to me the best course of action here would be to replace both R480 and R488 with resistors matching the values on your board, no? What would you say are the odds of my board, with the different layout, having resistors in these exact locations using values that don't match yours? Feel free to speculate if necessary - your speculation can't be any worse than mine!

[L29Ah]

My mobo seems to have the same layout as bcn's. R480 is measured to have 10kOhm. Just in case it's renamed, I've verified that it connects pin 3 (WP#) to pin 8 of the flash chip. Also, R488 is 28Ohm and connects pin 3 to something else, likely the EC.

Many thanks for checking. I have passed this on, and upon testing, it seems R488 on my board is also busted, as it measures infinity. So I guess that will have to be replaced as well.

Given that you both have the other layout, and my board was claimed to be a development board, I guess the chances of finding someone with the same layout as mine are slim..? If @flyingfishfinger was able to check the layout of his board as well, I suspect he would find the same as both of you (though confirmation would be great if possible, of course).

So, based on my still rather limited understanding of electronics, it seems to me the best course of action here would be to replace both R480 and R488 with resistors matching the values on your board, no? What would you say are the odds of my board, with the different layout, having resistors in these exact locations using values that don't match yours? Feel free to speculate if necessary - your speculation can't be any worse than mine!

Grab a multimeter and check if they are connected to the same things as on ours, then it'll likely be a good plan. Also did you check if the laptop works w/o doing anything to your resistor condition?

[yitzhaq]

So, based on my still rather limited understanding of electronics, it seems to me the best course of action here would be to replace both R480 and R488 with resistors matching the values on your board, no? What would you say are the odds of my board, with the different layout, having resistors in these exact locations using values that don't match yours? Feel free to speculate if necessary - your speculation can't be any worse than mine!

Grab a multimeter and check if they are connected to the same things as on ours, then it'll likely be a good plan. Also did you check if the laptop works w/o doing anything to your resistor condition?

The problem with the latter suggestion is logistics, unfortunately. (Only) the board is now in a different country from me, whereas I have the rest of the laptop still here. Thus the guy who currently has the board can't really check anything that can't simply be gleaned from the board itself, and I can't test it until I get the board back, and re-assemble everything back together. At which point it will already be too late to make any further changes (without having to ship it back, which I'd really, really rather not have to do).

Had I known any of this would arise I would've just sent the whole laptop from the start - we both thought he would simply be replacing the BIOS chip with a socket, and that would be it. These resistor issues were only discovered once that operation was underway. And given how much I've fiddled with it myself from before trying to get a working BIOS back onto the (previously soldered) chip, and how long ago it's now been since it last had one, I also don't know what possible problems it may now have, or have had from before. Hence my strong desire to get anything and everything that may need fixing identified and fixed during the present window, and the challenges associated with trying to guide someone essentially working in the blind. And having to make decisions about a board seemingly somewhat unlike everyone else's, with no schematic to work off of, and an unhealthy amount of guesswork and speculation required, all while trying to convey details about electronics stuff I myself - as a software guy - have precious little knowledge about.
Thus I greatly appreciate your (and his) patience!

Anyway. I will ask him to go the multimeter route, and hopefully that'll bring us as close to a definitive answer as we can get here - and hopefully close enough to act with some confidence. I have forwarded your description, and hope this'll give him enough detail.

[flyingfishfinger]

Hi, sorry for the delay. Both of my boards match what the others have posted with the resistors stacked vertically (=) instead of next to each other (--). Good luck on the repairs!

[yitzhaq]

Hi, sorry for the delay. Both of my boards match what the others have posted with the resistors stacked vertically (=) instead of next to each other (--). Good luck on the repairs!

Thanks, and thanks a lot for checking! Seems everyone has a different edition than mine, then.

[yitzhaq]

Grab a multimeter and check if they are connected to the same things as on ours, then it'll likely be a good plan. Also did you check if the laptop works w/o doing anything to your resistor condition?

A few quick follow-up questions from the guy working on my board (summarized as best I can - please excuse any misunderstandings on my part):

* Was the BIOS chip still in circuit (i.e. on the motherboard) when resistance values were measured?
* Did you use a standard multimeter or a 4 wire resistance meter, and were the resistors still in circuit or removed from the board when measurements were carried out?

Many thanks again.

[yitzhaq]

Grab a multimeter and check if they are connected to the same things as on ours, then it'll likely be a good plan. Also did you check if the laptop works w/o doing anything to your resistor condition?

A few quick follow-up questions from the guy working on my board (summarized as best I can - please excuse any misunderstandings on my part):

* Was the BIOS chip still in circuit (i.e. on the motherboard) when resistance values were measured?
* Did you use a standard multimeter or a 4 wire resistance meter, and were the resistors still in circuit or removed from the board when measurements were carried out?

Many thanks again.

Did you get a chance to see my last questions @L29Ah ?

[L29Ah]

A few quick follow-up questions from the guy working on my board (summarized as best I can - please excuse any misunderstandings on my part):

* Was the BIOS chip still in circuit (i.e. on the motherboard) when resistance values were measured?
* Did you use a standard multimeter or a 4 wire resistance meter, and were the resistors still in circuit or removed from the board when measurements were carried out?

Many thanks again.

Still in circuit. Standard multimeter. Made sure the measurements don't drift like they do when one incidentally charges some capacitance with it.

[755cdxd]

TL;DR

NOR flashes on libreboot systems run on 3.3V DC or 1.8V DC, and this includes data lines. CH341A has 5V logic levels on data lines, which will damage your SPI flash and also the southbridge that it’s connected to, plus anything else that it’s connected to.
Please do not buy the ch341a! It is incorrectly engineered for the purpose of ROM flashing on systems with 3.3v SPI (which is most coreboot systems). DO NOT USE IT! This issue still isn’t fixed by the manufacturer, and it doesn’t look like they will ever fix it.

https://libreboot.org/docs/install/spi. ... use-ch341a