Bug in Intel Atom C2000 series processors?

Discussion in 'Processors and Motherboards' started by smithse79, Feb 6, 2017.

  1. Jyrki

    Jyrki New Member

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    Have you guys looked those reworked boards really carefully? I assume there would be one or two tiny smd resistors added somewhere. I would rather rework solder those myself than wait 2+ weeks for board returning back.

    Edit: I looked around docs a bit. I woud guess JTMP1 (TPM header/Port 80 header) has resistor from pin 1 to +3.3V. +3.3V can be found from pin 9 of the same connector, but I would assume it is also available closer of pin 1 somewhere on the board. I don't have photo of back side of PCB and mine is installed in case and running. I would guess resistor is either 100ohm, 8.2kohm or 10kohm.


    Edit2,3: Those wondering steppings reported by software. Reported 0 = stepping A0/A1, Reported 8 = stepping B0. I don't know what stepping C0 reports. Also stepping C0 is reported as 8. There is another field showing it is C0 SoC. I assume because cpu part of SoC is unmodified.
     
    #81
    Last edited: Jul 22, 2019
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  2. weust

    weust Active Member

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    I finally had time to send Supermicro an email and received a response this morning.
    Was asked to fill out the RMA form and send to the RMA email address.
    It got approved already so I will be sending the board tomorrow.

    Once it's back I can use it as my FreeBSD poudriere en monitoring server
     
    #82
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  3. RageBone

    RageBone Active Member

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    @Jyrki cisco was reported to be switching from the first lpc clock source to the second, which was broken out and not connected to anything else.
    Possibly pulled low or what ever, keeping it from degrading.
    Hence the pictures of the weird soldered in resistor bridging pads.

    There was a discussion on the EEV Forum sifting through some documents and statements deciphering that the board level workaround was a 10K? Resistor between Clock and Data if i remember correctly. I probably don't please look it up again.

    Another way of reworking those boards would be to simply swap the CPU with a fixed one, so you won't see any "fixes" like CiSCOs

    I have a broken ASRack board from this family and i have looked for the second clock source, but it doesn't look to be even wired in on the board.
    It is also extremely hard do follow traces and vias since the BGA layout leaves a ton of space between pads making vias able to be grouped together differently then one sane person would assume.
    So XRay would be the only reasonable and not time wasting way of finding that. I sadly don't own one, or have access to such a machine.

    On the other hand, many Asrack Atom boards were reported to have other problems, so it might not be the clock gen that keeps my board from posting.
     
    #83
  4. AndyYin

    AndyYin New Member

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    I just fixed a bricked Supermicro A1sa7-2750f, the Motherboard is using Intel Atom C2750.

    https://www.supermicro.com/manuals/motherboard/Atom_on-chip/MNL-1555.pdf (Page23)
    TPM Header/Port 80 Header, A Trusted Platform Module/Port 80 header, located at JTPM1, right beside the DIMMB1 slot.
    Pin # Defnition Pin # Defnition
    1 LCLK 2 GND
    3 LFRAME# 4 <(KEY)>
    5 LRESET# 6 NC
    7 LAD 3 8 LAD 2
    9 +3.3V 10 LAD1
    11 LAD0 12 GND
    13 NC 14 NC
    15 +3V_DUAL 16 SERIRQ
    17 GND 18 Ground
    19 LPCPD# 20 NC

    The fix applied is by putting a 110 ohm pull-up resistor from LPC_CLKOUT0 to +3.3V. (PIN1 and PIN9).
    Hope this can help you or others guy may save already bricked MB.

    !!!! The red circle is a 110 Ohm resistor, DO NOT Connect the wire directly.
    rework.png
     
    #84
  5. weust

    weust Active Member

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    I got mine back this week, just need to test it. But the form shows it's tested and working so I have no doubt it will be fine.
     
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  6. AndyYin

    AndyYin New Member

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    Cool~, RMA is the best way for solve the AVR54 issue, they will replace the SOC to C0 stepping.
     
    #86
  7. weust

    weust Active Member

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    I did notice no extra soldering of a resistor, so that makes sense.

    RMA is indeed the best way, but if RMA wouldn't cover it anymore I would use your trick.
    Though I would use some special tape (the brownish one) to really make sure nothing conducts.
     
    #87
  8. AndyYin

    AndyYin New Member

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    #88
  9. Vidmo

    Vidmo New Member

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    Well, my Supermicro A1SRi-2758F finally had the issue arise today. It was running pfSense and was my primary device. I had another A1SRi-2758F in stand-by mode with all pfSense settings synced up. Just had to move the cable from the cable modem over to the stand-by and fire it up. Off to RMA land now.
     
    #89
  10. RageBone

    RageBone Active Member

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    @AndyYin
    Wasn't that resistor the Intel proposed board level workaround to keep the clockgen from degrading?

    Was yours actually bugged with no LPC clock?

    Mine currently fore sure has no Clock.
     
    #90
  11. AndyYin

    AndyYin New Member

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    No, it's not an Intel proposed W/A.
    Intel would like to ask you to replace SOC to C0 stepping silicon.

    more LPC clock refer intel AVR54
    http://www.intel.com/content/dam/ww...ion-updates/atom-c2000-family-spec-update.pdf (AVR54 on page 34)
     
    #91
  12. RageBone

    RageBone Active Member

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    Well, i thought the SERIQ pullup was to be a workaround for keeping the LPC from degrading.

    Had a deeper look at my Asrack C2550d4i and the interesting part is that it has 25MHz on the LPC clock pin except of the expected 33MHz and the IOclock of the SIO is not there.

    Both seem to come from a ICS Clockgen, so the Resistor mod didn't work here.
     
    #92
  13. gsrcrxsi

    gsrcrxsi Member

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    I assume you can see this in the BIOS? to check if a board you have on hand is or will be affected? the "good" stepping is C0? whats the bad stepping? anything else?
     
    #93
  14. Poirier

    Poirier New Member

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    Hi,

    I can confirme AndyYin's modification is working fine. My ex-dead A1SRi-2758F pfSense applicance is now alive again !

    Many thanks Andy
     
    #94
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