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Old 02-15-2020, 10:02 AM   #1
Dannyx
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Unhappy Samsung NP-R60s NO POWER (PRAHA_SRE Rev 1.1)

Good day folks. I've been struggling with this Samsung laptop for a while now and I decided to take a break and ask for some help, since I can't figure out what's wrong with it. The board is a PRAHA_SRE REV 1.1 board. I managed to find a schematic, but no boardview, so if anyone has one and would like to share it, it would be greatly appreciated.

Here's the deal: the laptop's totally dead - no power, no LEDs, not nothing.

To make the story a bit shorter, I thought I managed to isolate the problem to the Super I/O (KBC ?) IC in the pictures. It is a H8S/2110B. The reason I thought it was the issue is because if you look at the power sequence on page 3 of the manual I attached, the S5/S4 rails on the left are all present, but I can't get into the S3 state, in other words KBC3_SUSPWRON doesn't go high and since that signal is supposed to come from the KBC, I assumed it's faulty and proceeded to finding a replacement. I found some on Aliexpress and ordered 3 of them, though I didn't actually do any research beforehand to know whether these require any sort of programming, which leads us to today when I finally got around to replacing it. The operation was annoying to say the least: took a VERY long time to finally get a new one on there. It was a bit of a disaster all throughout: I knocked some of the neighboring parts off when the chip finally came loose and I failed to pull it up with my tweezers and instead it slipped sideways. Fortunately, I had the forethought to take a picture of the area and only a cap and a resistor moved, so I managed to put them back. My repair didn't work unfortunately: same exact problem as before: no power at all.

I wasn't satisfied with the job I did on that chip: it wasn't quite lined up properly, maybe some of the pads weren't touching the pins, since I was a bit too ambitious to solder it back with my hot air station rather than using the soldering iron to drag-solder, so I thought the extra heat had an unwanted effect on it too, so I ended up removing the replacement chip and replacing it again, this time using my iron all throughout. The picture shows the last chip after I soldered it.....looks decent enough if I may say so myself and the pins appear to be soldered correctly. I inspected it up close as much as I could with my magnifier, since I don't have a microscope and crossed my fingers: still nothing......at this point I was pulling my hair out and not having any other choice (other than to maybe try and waste my third and final IC), I thought I'd take some measurements again to see if anything has changed. Same story as before: I'm stuck in S5/S4, with no KBC_SUSPWRON.

There's another thing I noticed: no 3.3v on the power switch either ! If you follow the line KBC3_PWRSW, it should lead you to page 43 where the buttons SW2 and SW1 are. SW2 is the power key and SW1 the other button next to it which I don't care about at this point. If you follow KBC3_PWRSW some more, it will take you to page 40 to the right of the KBC (U10) where there's a pull-up resistor, R251, pulling the line up to MICOM_3.3v. The power rail is present, but that KBC3_PWRSW is not pulled high, so something's definitely not right there. Unfortunately I have no way of finding out where R251 could possibly be located, hence why a boardview would be required in such cases, since there's too many resistors to measure by hand. Annoyingly enough, the other button SW1 HAS 3.3v on it, but it doesn't do anything either ! There's no short to GND on the PWRSW line, though if I try to jump 3.3v from the button next to it, it goes low, so it's like there's a short somewhere on that line....

I'm not sure what to try next....does that KBC chip require programming ? This was the fatal flaw of this repair attempt: not knowing whether a "blank" chip could work on there. Is there a way to program it to get it going ?!

Speaking of which, this might explain why there's no power on that pin: if it's like the controller on an Arduino board, the pin could be configured to be LOW, hence why it pulls the line to GND and stays that way....just a thought to further push this board towards the trash bin
Attached Images
File Type: jpg 20200215_170918.jpg (916.4 KB, 9 views)
File Type: jpg 20200215_170509.jpg (837.1 KB, 10 views)
File Type: jpg 20200215_171013.jpg (429.3 KB, 11 views)
File Type: jpg 20200215_171023.jpg (346.8 KB, 7 views)
Attached Files
File Type: pdf NP-R60FE0A_SER_SM_EN_20080602190217734_04_Schematic_Diagram.pdf (1.43 MB, 8 views)
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Old 02-15-2020, 02:17 PM   #2
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Default Re: Samsung NP-R60s NO POWER (PRAHA_SRE Rev 1.1)

Yes, H8S are microcontrollers with internal ROM that require to be programmed. I never worked with those microcontrollers so dunno how to program them, but it's most certainly doable with the proper programmer. Getting the firmware to put on it could be an issue though…
I'd put back the original chip that has the correct programming on it and check the power button signal again. Note that according to the power sequence in the schematics, RSMRST# appears after triggering power button on this board.

As for soldering, remove it with hot air, apply flux on the pads, wick the pads, clean flux with alcohol, place new chip, hold the chip with tweezers, wet your soldering iron with some tin, touch one of the corner pad+pin to tack it down, do the same with an opposite corner making sure chip is aligned properly. Doesn't matter if it looks ugly or if pins are bridged at this point, it's just to hold the chip in place. Apply flux all around, apply some solder to one of the side that you didn't solder previously, drag the soldering iron across all the pins of this side, clean the excess solder from the iron tip, pick up the excess solder on the chip's pins, clean tip again, repeat until there's no excess solder on the pins anymore while applying more flux if necessary. Then do the other sides the same way, and finally clean the flux with alcohol.
Good solder, decent flux, appropriate tips are keys to success here, it really makes a huge difference using proper tools and supplies.

On the 3rd picture, it's a bit hard to tell but it looks like the chip is somewhat misaligned and left and top sides are not soldered properly, but might be just an illusion.
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Last edited by piernov; 02-15-2020 at 02:18 PM..
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Old 02-15-2020, 02:48 PM   #3
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Thumbs up Re: Samsung NP-R60s NO POWER (PRAHA_SRE Rev 1.1)

Quote:
Originally Posted by piernov View Post
Note that according to the power sequence in the schematics, RSMRST# appears after triggering power button on this board
What is this signal doing exactly and how would it be related to my problem ?

Yeah, it means it's got a blank chip on there now....I still have the old one, though I sure hope it's still functional after I blasted it with hot air...

If I remember correctly, there was no power on the button the first time around either, though MICOM_3.3v was still present, since it's the VREG linear regulator of U529, so it's always there, unless shorted which it isn't...
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Old 02-15-2020, 05:40 PM   #4
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Default Re: Samsung NP-R60s NO POWER (PRAHA_SRE Rev 1.1)

I don't exactly know how it's done on AMD platforms, but on Intel platforms RSMRST# is one of the southbridge reset signal, and it's required to go out of S5 state. Without it the southbridge won't go to S4 and S3 state, so you won't get your S3 rails.
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Old 02-16-2020, 03:46 AM   #5
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Default Re: Samsung NP-R60s NO POWER (PRAHA_SRE Rev 1.1)

But in this case I'm not getting the stuff before RSMRST anyway, so I don't think it's a priority yet. Besides, it comes out of the KBC too, so if there's a problem with it there's nothing I can do to fix it....unless I can somehow find a way to program it AND the stuff to put on it....
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Old 04-04-2020, 07:51 AM   #6
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Thumbs up Re: Samsung NP-R60s NO POWER (PRAHA_SRE Rev 1.1)

Ok guys, just in case someone is still watching this thread and willing to provide their two cents, I dug deeper, not wanting to admit defeat (and also because this corona sh!t combined with my two week furlough gave me nothing better to do) and I THINK I'm back on track with this junker.

Just a quick refresher: my initial assessment, which could very well be incorrect entirely, lead me to believe the KBC (MICOM as they call it) is dead or corrupted, so I got myself some similar chips off Ali, unaware at that time that they need programming. I soldered one in place and of course nothing happened, since I quickly learned these H8S chips require programming. Now two separate problems opened up: I have no idea how to interface with the chip to burn it and even if I did, I wouldn't have anything to write to it, since I don't have the contents of the KBC. Yesterday however, I managed to find what's inside the "Samsung Update" ZIP file I attached.

After a lot of translating and piecing together various pieces of information from various sites (most of which, if not all, were not in English), I learned that the KBC's content can be obtained from the BIOS update utility which you can get from Samsung for your model. The model described in the article isn't exactly like mine, but still a Samsung, so close enough. I followed the instructions and sure enough I ended up with a couple of files. There's two pairs of matching .WPH and .BIN files in there. The 1Mb .BIN files would seem to be for the KBC, since they match the 1024Kb size. The .WPH files seem to be the BIOS itself....I don't know why there's 2 sets of them though or why the random .WPH extension, instead of a .ROM .BIN or .FD....anyway.....Samsung.......

Now comes the crap part: assuming, in the best of all possible scenarios, that one of those .BIN files should indeed go on my blank H8S chip I got of Ali, how do I get it on there ? I don't know squat about programming, but my limited knowledge, having messed with TVs for a while now, tells me this H8S jobbie does serial. Page 261 and onward in the PDF describes this, but other than a few terms I recognize, like "serial" and "UART" and "CLOCK", the rest of that stuff goes a bit over my head....do these require some special hardware to program, or would the cheap and cheerful CH341 we all know and love do the job somehow ? Cheers guys. Thanks.
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Last edited by Dannyx; 04-04-2020 at 08:08 AM..
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Old 04-04-2020, 08:54 AM   #7
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Default Re: Samsung NP-R60s NO POWER (PRAHA_SRE Rev 1.1)

Those general purpose MCU often have a lot of interfaces like UART, I2C, SPI, JTAG, etc… but it doesn't necessarily mean you can use all of them to program the internal ROM, it really depends on the chip.
Apparently the currently-supported official tool to work with the H8S family is the E8a:
https://www.renesas.com/us/en/produc...lator/e8a.html
It's not gonna be cheap. Maybe there are older models for cheaper, maybe clones exist as well, but to know that it's gonna require spending some time on Google.
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Old 04-04-2020, 09:39 AM   #8
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Default Re: Samsung NP-R60s NO POWER (PRAHA_SRE Rev 1.1)

Yes, that's extremely expensive indeed....makes absolutely no sense to spend that amount of money for a single repair on something this old, which you're not sure it's going to succeed to begin with.....even for a repair shop it would still be prohibitive, given the very low number of uses it would see. That money could go into a decent microscope. Looks like that puts an end to this
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