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How To Pinpoint Cause Of Mainboard Problems

By on May 8, 2019
pc post card











These are excellent times to upgrade an older PC with a new faster mainboard, or just to upgrade a mainboard with a faster quad-core microprocessor, because for just about 20 Dollar/Euro these quad-cores can easily be found used but tested on eBay or Aliexpress. For instance the Intel Xeon (R) 3.16 GHz X5460 CPU was bought with one year warranty and it now already works about 2,5 years without any problem on my also second hand Asus P5KPL-AM SE computer. Which was originally an Intel Dual-Core Desktop PC.

I recently only replaced the original Dual-Core Intel Fan with a better Cooler Fan with 4 pipes, a Cooler Master Hyper H412R /AM3, which will guarantee the longer life span of my CPU quad-core. It already helped cooling down the CPU temperature by about 30 degrees Celsius! (It was about 65 degrees Celsius normally, which is close to the limited maximum). My new Cooler really makes a difference and came with both universal mounting brackets for AMD and Intel LGA775 mainboards.

That is the reason why my brother also decided to buy the same older P5KPL-AM SE mainboard second hand plus the same quad-core Xeon processor. And 2 DDR 2GB 800MHz modules were also bought for just 9.09 Euro. Below is shown his ‘new’ P5KPL-AM SE desktop computer case that is replacing his previous much older mainboard computer.

computer motherboard repair

Everything worked fine until he was almost ready with installing a new Windows system with the use of his external USB memory stick. After a reboot he lost his video output signal. And both VGA (the original on board VGA chip) and neither his HDMi Video card worked afterwards. So after a long search he brought his computer to me to examine the failure. Luckily I could test his mainboard with my PC_Debug_Series_Card also known as DEBUG KING with LCD Host, MiniPCIe/MiniPCI/LPC (3-in-1 Interposer) and PCI Interposer slot card.

 PCI Interposer slot card

I used above shown PCI Interposer Card with LCD Host. After I had inserted this card and had switched on his computer it showed a running clk signal on its clk led and on its two 7 segments display an end code of “32” after it stopped changing. And on the LCD display it gave the text that it was an undefined Post error which could originate from the Ami Bios. So I took out the Winbond 25X80AV DIP8 Bios chip and flashed it with the correct Bios content from my own identical mainboard.

Which is easy with this tool: the ‘Universal BIOS Backup ToolKit 2.0.exe’. After that small program (use administrator rights to start it if you use Windows 7 or higher!) saved my 1MB ROM to my harddisk I used my RT809H to write it into his Bios chip. And I placed his Bios back in its mainboard socket.

After that everything worked again splendidly and both his computer VGA and HDMi output were back again! And I was glad it was solved. But about 5 days later my brother phoned me that he lost his Video output again after installing some new programs by using an external USB memory stick again. Apparently it looks like that these Asus mainboards are somehow sensitive to external boot sequences by corrupting the internal Bios chip in the process. Also because these mainboards are designed with an easy method to reflash a corrupt Bios. It can be done at Boot by using keys ALT-F2, or by using the EZFlash utillity, or by booting from CD or Fat16/32 USB memory stick. Which doesn’t seem to work by booting from the original Asus mainboard anyway because the DVD never boots although it is explicitely mentioned on the DVD that it does which never works, no matter which PC I tried!

So he brought his computer over and I re-inserted my PCI Debug card and switched on his computer. It showed a running clk signal led, and an end code of “E1”. And the video outputs indeed didn’t work again. So I let it reboot by pressing the RESET button on the front, and another end code of “81”appeared. Next LCD diagnostics messages are shown in full color!

pc post card

Next photo shows error message BIOS 81 I got on this American Megatrends Inc. computer. Both LCD POST diagnostic messages indicate that the Memory modules and/or the Bios are at fault.So I started by removing one DDR2 Ram module from its mainboard and I concluded that if I removed the module that was closest to the EATX Power connector (slot DIMM_B1), the Asus mainboard booted again fine with working Bios boot , video output and working Num lock led on/off on the Keyboard.

I also checked out if both modules worked if only placed in DDR2 DIMM_A1 (64bit, 240-pin module), leaving slot DDR2 DIMM_B1 (also 64bit 240-pin) open. They both did so were fine! Slot DDR2  DIMM_B1 could be defect. But to rule out that conclusion I also tested both slots with my older 667MHz DDR2 240-pin modules which made no difference. And I rechecked the Bios 25x80AV chip. My RT809H programmer showed it had a verify error at startposition 0xC8AFD.

So it again was a good reason to reflash/rewrite my brother’s Bios again.

bios check post card

bios check post card repair

Previous RT809H screenshot clearly indicated that the Bios was corrupt again after it was compared with the original saved ROM file on my harddisk. And obviously there was nothing wrong with the 240-pin DDR2 memory modules.

ram ddr2 module

Next photos show the end Post diagnostic code that the PCI inserted Interposer Card showed. First code E1 followed by code 81 after a reboot. Also good to know is that my other programmer, the TL866, completely failed to Verify this 25x80AV chip after it was programmed. It never Verified completely which was no problem for my RT809H at all!


It sure helped to have this Post Diagnostic PCI card running in this problem mainboard after the video output was completely lost! And after the Bios chip was re-inserted the Asus P5KPL-AM SE booted fine again with both DDR2 Ram modules! It all matches with the Post codes that were given.

pc pos card detect fault

how to repair pc motherboard

Previous photo showed that the Windows 10 boot screen was back. And I was happy I could fix my brother’s computer again. Probably he will be more careful when using USB memory sticks while booting on these Asus mainboards that all have the EZ Flash utility which could mean more trouble if the Bios gets flashed unintendedly in the process.

But just in case his Bios chip is going bad he bought 5 of them new for 2,5 Euro on Aliexpress. And flashing/writing them outside his mainboard is never a problem for my RT809H. Which I upgraded yesterday to new version 20190418. It only took me about 1,5 hours just to log in on the bad ifixit China site because of the terrible security question I never used but couldn’t avoid. Which kept me waiting over and over for another 15 minutes until that security question disappeared and my login registration was finally accepted.

I noticed on Aliexpress a lot of new test hardware tools, including DDR2 and CPU test boards. Which were not at all expensive. Maybe they will be something nice for some future repairs. It is always nice when something that looks like a hopeless situation afterwards gets easily fixed. And again at no real cost, of course not counting time and the rather expensive programmer used.

albert from netherlands

Albert van Bemmelen, Weert, The Netherlands.

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Note: You can read his previous repair article in the below link:




  1. Mohamed Siddiq M

    May 8, 2019 at 10:07 pm

    Dear Sir
    Every time your article briefly explain. All the best.
    Mohamed siddiq M

    • Albert van Bemmelen

      May 8, 2019 at 10:59 pm

      By the way: After the Bios was reprogrammed and the mainboard was fixed, the PCI diagnostic board showed code "AA" on its display.

  2. Ghashaan

    May 8, 2019 at 10:15 pm

    Great article!

    • Albert van Bemmelen

      May 9, 2019 at 3:02 pm

      If you want to know more about the DEBUG KING diagnostic card maybe this link is a good read:

      • Ghashaan

        May 9, 2019 at 11:32 pm


  3. Albert van Bemmelen

    May 8, 2019 at 10:56 pm

    All the best to you too Mohamed! Have a nice day!

  4. Robert Calk Jr.

    May 9, 2019 at 5:50 am

    Good job, Albert! Someday I will upgrade to the better programmer.

    • Albert van Bemmelen

      May 9, 2019 at 2:07 pm

      My shop owner friend Chafik is convinced he needs the RT809H programmer too, but the fact that he previously also bought the Genius G840 and the TL866 universal programmers that now are hardly useable is holding him back. But he already used my RT809H a couple of times when the TL866 failed doing the job. And with the RT809H he was easily able to flash and revive the Bios chips in expensive laptops a couple of times. I already owned 3 other universal programmers before the RT809H and they all have their specialties. Like the Xeltek SP/L that was my first very expensive programmer I already wrote about in a previous article.

  5. Lynn Blakely

    May 9, 2019 at 6:10 am

    Very good use of a fine test tool. I will have to reread your diagnostics to completely understand how you determined that the use of the flash drives corrupted the bios, and all the symptoms that caused. Thanks for an excellent explanation on use of the diagnostic card with made the repair possible.

    • Albert van Bemmelen

      May 9, 2019 at 2:37 pm

      Using the DEBUG KING Diagnostic card is easy if all available Post message are known. But since every mainboard manufacturer uses another set, it makes finding the exact complete list difficult. And they are not given with the Diagnostic card. Therefore the pre-programmed text in the DEBUG KING that is shown on its little LCD screen is a great help for diagnosing the problem. The tool therefore can be switched to the right Bios type. It knows the BIOS Post codes of AMI/AWARD/PHOENIX/EFI mainboards. (over 1000 items with photos are saved in the diagnostic EEPROM). The manual also says that users can download and upgrade new version data in the EEPROM from their website but I do not know if there is a new version available.

      • Robert Calk Jr.

        May 13, 2019 at 5:45 am

        Sounds good. I also left another comment on your "crystal" article.

  6. Jairo. Cuellar

    May 9, 2019 at 1:59 pm

    This tester work for TV mainboard.

    • Albert van Bemmelen

      May 9, 2019 at 2:48 pm

      The RT809H works for TV mainboards Jairo. The Debug King diagnostic card of course only fits in PC mainboards.

      And if you also want to upgrade your desktop computer mainboard to a quad-core cpu, you must make sure that your mainboard uses the right chipset version! In case of our Asus P5KPL-AM SE mainboards it is the supported Intel Northbridge G31 chipset.

  7. Yogesh Panchal

    May 9, 2019 at 3:38 pm

    Good job!Albert

    I have seen some motherboard brands using dual Bios design one is main Bios and another is backup Bios but when this type of error occurs we found both the bios gets corrupted nothing in backup Bios also and we have to arrange it from some another Working board.

    • Albert van Bemmelen

      May 9, 2019 at 5:04 pm

      You are right about that Yogesh. Having several computers standby with a few universal programmers to avoid that problem is mandatory. Although I must say that our Asus P5KPL-AM SE mainboards do have a very decent EZ Flash routine in de Bios setup menu. But I wonder why they call these mainboards BIOS_Crash_free if the video output disappears and setting up the EZ Flash option is not possible afterwards. Especially if booting from USB stick or CD-ROM to repair the corrupted Bios fails.

  8. Justice

    May 9, 2019 at 3:43 pm

    Hey wow Albert too complex but very interesting article!!. Keep up these wonderful trends for us to follow from other part of the world, exciting stuff.

    • Albert van Bemmelen

      May 9, 2019 at 5:26 pm

      You are right about the exiting stuff that is going on in the world of Electronics Justice! We citizens of the World of today Eat, Drink and Live by Electronic technology. Even money has become digital now and it is only a question of time before even our meals will be cooked and ready out of some 3D food printer.

      • Ghashaan

        May 10, 2019 at 1:47 am

        "Our meals will be cooked and ready out of some 3D food printer." Albert van Bammelen

        This is a line to remember. You have good sense of humor.

      • Robert Calk Jr.

        May 11, 2019 at 6:20 am

        I am not eating anything that comes out of a 3D printer!

  9. Parasuraman Subramanian

    May 10, 2019 at 3:56 pm

    Excellent informative article, but beyond my scope to attempt!

  10. paul

    May 10, 2019 at 11:18 pm

    Je bent me er eentje Albert "fantasties" ben hier in Zuid Africa voor 65 jaar en huidig 79 jaar oud, mad about electronics but only a beginner hobbyist, love your contributions,and I am a subscriber to for at least 5 years.
    You are me one Albert "fantasties" am here in South Africa for 65 years and currently 79 years old, mad about electronics but only a beginner hobbyist, love your contributions,and I am a subscriber to for at least 5 years.

    • Albert van Bemmelen

      May 12, 2019 at 10:25 pm

      Hoi Paul. Bedankt voor jouw leuke reactie. Ik weet dat we onze maaltijden nog niet op deze manier thuis kunnen bereiden, maar het is eigenlijk geen fantasie meer, omdat ze al experimenteren met voedselprinters in Eindhoven en waarschijnlijk ook elders. En ze gebruiken in mijn land ook al 3D-printers die metershoge muren van beton zeer snel en zeer nauwkeurig maken. En zelfs bruggen!
      (Ik heb een 3 jaar jongere broer die ook Paul heet die in Den Haag woont. Plus nog 3 broers en 2 zussen).
      Hi Paul. Thanks for your nice reply. I know that we can't make our meals this way at home yet, but it actually is no fantasy anymore because they are already experimenting with foodprinters in Eindhoven and probably elsewhere too. And they also already use 3D printers in my country professionally that make walls of concrete very fast and very precise. Even bridges!
      (I have a 3 year younger brother also called Paul living in The Hague. Plus and 3 more brothers and 2 sisters).

  11. Albert van Bemmelen

    May 11, 2019 at 5:08 pm

    Computers are much fun and without them we wouldn't have digital testers nor universal programmers Parasuraman. And since even our modern smart tv's have computers it is the more reason to embrace this new technology. A world without them isn't thinkable anymore and I'm sure you limit yourself for no reason thinking it is beyond your scope! Especially after seeing all those expert repairs you did that required so much patience!

  12. ulises Aguilar pazzani

    May 31, 2019 at 6:52 am

    Great fix My Friend

  13. Albert van Bemmelen

    June 13, 2019 at 2:02 pm

    Muchas gracias Ulises. After a new Bios 25x80 chip was programmed and inserted on the motherboard's eeprom socket, also the previously not working LAN connection was fixed! That also was a problem that related to the originally bad corrupted Bios IC. And the right drivers for Windows 10 only then were automatically found and every part of the P5KPL-AM SE mainboard was restored and functional!

  14. ulises Aguilar pazzani

    June 15, 2019 at 1:12 pm

    grate job SIR


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