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    Intel DQ45CB No Boot

    Hello,

    I have two Intel DQ45CB Based PC's. One works, the other does not.

    When power is first applied to the working one, it will immediately start up, and shut down again after about 5 seconds. Upon pressing the Power Button, normal boot up occurs.

    When power is applied to the faulty one, you just get the Green Motherboard Power LED on. IF the power button is pressed, the CPU fan goes full speed, but there is no display output to the onboard DVI connector (or graphics card when fitted), there are no beeps.

    I have removed the RAM, Graphics card, all front panel connectors, drives etc, changed the PSU, all with no change in behaviour.

    I have replaced a capacitor which had shown signs of bulging (only one capacitor on the board is bulging) with no change.

    I did try booting with the 4-Way CPU power plug removed, and then when powered up the CPU fan ran slower (don't know if that helps or not!.

    All board fuses are OK.

    The voltage across the replaced capacitor is about 1.1v (Capacitor rating is 6V3 1500uF)

    I have checked the various larger transistors, and none seem short circuit.

    I don't know the history of either PC, so cannot say what the trigger of the cause may have been on the faulty system.

    This is the first motherboard I have attempted to repair.

    I don't know where to start other than supply voltages on the board, so some tips would be great.

    Any help gratefully received

    #2
    Re: Intel DQ45CB No Boot

    Hi Russ17
    Can you post a picture of the mother board and which capacitor you changed?

    It sounds like it was on Vcore (if it has about 1.1V across it) but I would like to be sure you do have Vcore to the processor.

    Your motherboard has a PCI slot so I would suggest you get a POST code analyser as they are very cheap and often give at least some idea of what is going on.... or not going on. There are loads of them around on ebay and elsewhere, something like this would do fine. They are quite useful if you want to start repairing motherboards

    https://www.ebay.co.uk/itm/PC-Mother...Cclp%3A2334524

    Or pay a few quid more and get one form a UK supplier if you don't want to wait
    https://www.ebay.co.uk/itm/PC-PCI-Di...AAAOSwl5dfVq0p
    Last edited by dicky96; 02-08-2021, 02:03 PM.
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      #3
      Re: Intel DQ45CB No Boot

      Hi dicky96,

      Thanks for the advice and taking the time to reply.

      I looked at the user manual for one of these PCI Testers, but from what I can see, no matter what error code it gives you, it wont really help diagnose the issue to a point where a fix, other than changing capacitors, would be a course of action. The chance of finding an individual SMD Transistor or IC on the MB, removing it and replacing successfully, is slim to none.

      The capacitor I changed was not near the CPU, so not sure if it is supplied from VCore. It is located near the Graphics slot.

      I managed to remove the capacitor, but was unable to clean the hole out to receive the replacement, so I did a temporary fix (which looks very amateurish for someone with 30+ years of soldering experience, hence why I am reluctant to post a picture!) for test purposes, as I didn't want to lift any tracks on the reverse side of the board.

      My so called "re-work" station could not get enough heat into the foil, even at 400C!

      I measured the multiple transistors (MOSFET's?) around the CPU, which all seem to be in parallel. The output on all the transistors is around 1.1V too, so I am going to guess that they provide VCore from the 12V CPU connector (4 Pin, 2x Yellow, 2x Black).

      One thing I noticed was that measuring resistance between the alleged VCore and Ground (PSU disconnected), gave around 7 Ohms resistance when a CPU is fitted, but open circuit when no CPU is fitted. The same is true when a different CPU is fitted - I cannot prove that either CPU is functional however.
      Although I have no previous experience, this resistance seems very low, which could be causing the VCore to be dragged down, but I may be wrong.

      When time allows, I will check the resistance, at the same point on the MB, on the working system.

      Russ

      Comment


        #4
        Re: Intel DQ45CB No Boot

        Hi dicky96,

        I just booted the other system into BIOS.

        In Hardware monitoring, you can see the different voltages.

        12V & 5V are good

        3.3V is 3.28V - Good

        there are two others (one was VCC I think) and both were 1.12V, so compares well with the faulty system, which with my DVM was 1.1V.

        So we are back to square one.

        Comment


          #5
          Re: Intel DQ45CB No Boot

          @Russ17
          No, the low resistance you are seeing (7 ohms) is the resistance of the CPU. It is normally low, in fact on modern CPUs it can read very low, pretty much like a short. And that is normal.

          If you think about it, with Vcore of around 1V, the CPU would have to be low resistance for any appreciable amount of current to flow.

          Yep those MosFETS in parallel near the CPU will be generating Vcore and the 1.1V you are reading is within the expected voltage. Yes they generate Vcore from the 12V supply, usually from the 4, 6 or 8 pin ATX12V connector.

          The easiest way to remove solder from the holes, without any high cost equipment, is to use a hot air station (or even a hair dryer at a push) to warm that area of the board to about 100C-150C, then use your soldering iron plus desolder braid plus flux to draw out the solder while the motherboard is still hot. In my experience braid alone doesn't work. Also pushing a needle or even the leg of a resistor through the holes will help. Probably a resistor leg will jam in the hole. That's OK, cut off the part of the leg that went through the hole as this took most of the solder with it, reheat and remove it. Doing this several times often clears the hole.

          If you are seriously interested in repairing motherboards, and don't mind spending some money - then a T12 soldering iron works wonders. Previously I used a 60W ZD-916 iron and it just wasn't up to this job. From a personal recommendation you will not go far wrong with the T12 type of soldering iron.

          For the T12, use BC3 or BCM3 tip for desoldering capacitors and cleaning holes with braid and flux. Get a smaller tip for general solder work.

          This doesn't need to be super expensive.

          One of these KSGER T12
          https://www.aliexpress.com/item/4000...archweb201603_

          Plus a BC3 Tip about £4, some 60/40 leaded solder to help the unleaded sh!t melt, get some desolder braid and NC-559-ASM flux.

          This T12 will serve you very well. If you can get one with this type soldering iron handle even better IMHO, but some folks do have their own opinion
          https://www.aliexpress.com/item/1005...archweb201603_

          And one of these hot air station is good enough (this is probably like you have anyway)
          https://www.aliexpress.com/item/4000...archweb201603_

          Together these two will work wonders and handle pretty much all motherboard soldering/desoldering jobs when used properly. There are plenty of other recommendations in the soldering techniques section of the forum.

          Yeah you can spend more, I also have the vacuum desoldering tool and that works wonders cleaning out holes, when combined with my hot air station, but the above two will get the job done. I also have the Quick861DW hot air station which I swear by now, but my old 858D is still here and works very well if used properly.

          Apart from all that, 'improvising' or 'bodging it' as you did is also generally considered an acceptable technique on this forum

          Regards the PCI POST test cards - yeah I agree that the various codes don't always tell you what is actually wrong, but they are very useful to determine if the processor is actually trying to boot or not. They are inexpensive and I think most of the guys here trying to fix motherboards have one or more of these analyzer cards. They give you at least some idea if you have a board that powers on, all the voltages look good, but nothing apparently happens (no beeps no picture).

          This is the problem on your board. Have you tried with no ram installed?

          Various possibilities include no clock to the CPU, the CPU is held in reset, faulty/corrupted BIOS, some other voltage missing, some boards will not boot if the CMOS battery is drained, boards generally won't boot if the RTC oscillator isn't working. The PCI POST tester codes would give us at least some idea.
          Last edited by dicky96; 02-10-2021, 04:52 AM.
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            #6
            Re: Intel DQ45CB No Boot

            Hi dicky96,

            Thank you very much for the soldering recommendations and the detailed reply - I do appreciate your time and effort.

            I have a YiHua 968DA+ https://www.amazon.co.uk/Yihua-Solde.../dp/B07M69YMSK which is just over a year old, but seemed to loose its ability to produce anywhere near the stated temperatures ater about 3 months of infrequent use.

            Regarding the de-soldering, I used my hot hot to pre-heat, then the iron, with de-solder braid and flux paste, but no joy, and I have suffered my share of lifted tracks on more sturdy PCB's than MB's in the past to know when to stop!!

            Regarding the VCore, it would appear then that power supply is not the issue as all seem to be in range, and both CPU's "may" be good.

            I have tried with RAM and without, and swapped from the other system which works.A number of years ago, i spent a whole day in my job trying to fix a "dead" PC which turned out to be a dead CMOS battery - lesson learned.

            I noticed that the CPU fan at the instant of switch on is "normal" speed, then after a second, goes full speed. Could this indicate that the MB is detecting an over temperature of the CPU or a faulty fan thermistor (I assume the fan has a thermistor in it to measure heatsink temperature- I have never needed to know?)

            As you said though, no beeps, no screen, but full speed CPU fan. The system also doesn't do a "quick test" when power is initially applied to the PSU, as the other system does - almost a "pre P.O.S.T."
            Maybe this indicates an issue on the system which is checked before the system is powered up manually (e.g. thermistor fault etc)

            I have a Gateway PC (2005 era) which has a plug in thermistor which had a slightly high resistance joint on the plug, which caused the CPU to go too fast, but that didn't prevent the system from starting.

            Do you have any info on tests that may be performed during this "pre P.O.S.T." test?

            The "pre P.O.S.T." lasts long enough to spin the HDD etc, then just goes off, waiting for the front switch to be pressed, and then the system starts normally, with a few beeps at the start of the standard P.O.S.T.

            I cannot see what type of BIOS I have (using the working system as a reference) as it is not stated anywhere in the BIOS pages. Do Intel use their own BIOS?

            If I don't know what type of BIOS, the analyser wont be much help, as different codes give different causes based on the BIOS type.

            I tried another CPU Fan, Intel stock, and that doesn't go full speed at switch on, but system still doesn't boot.

            Comment


              #7
              Re: Intel DQ45CB No Boot

              Hi Russ
              Quick reply, I'll look at the other stuff in more detail tomorrow

              There is nothing wrong with your hot air - the problem is the soldering iron. That sort of iron with external heating element warming the tip is just old technology. Have a look on here or elsewhere for videos/reviews on T12 soldering irons which use a different type of tip. That one change alone meant I could work on even gaming motherboards.

              You will find my old threads on here about that too.

              Rich.
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                #8
                Re: Intel DQ45CB No Boot

                I found Intel document for this MB, showing Port 80h test codes on Page 84:

                Comment


                  #9
                  Re: Intel DQ45CB No Boot

                  I am still not sure what is being tested as power is initially applied. If I knew, it may uncover the reason for the non booting.

                  Comment


                    #10
                    Re: Intel DQ45CB No Boot

                    I guess from here it depends on what test equipment you have available

                    Fist I would be using a PCI POST analyzer to see if it is even trying to boot - this could tell us quite a lot.

                    If not I would also be checking the RTC crystal to see if it is oscillating (little cylindrical crystal near the cmos battery - marked 14.318) If that is not running the motherboard will not start.

                    This type of fault has many possible causes so we have to check the most obvious first. Finding the fault to some extent depends on what test gear you have.

                    As you have a good working board, a good look around with a microscope/magnifier would also be a good idea to see if something stupid happened like an SMD component broken off.
                    Last edited by dicky96; 02-10-2021, 05:07 PM.
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                      #11
                      Re: Intel DQ45CB No Boot

                      I have a couple of oscilloscopes, a couple of DVM's (one with Frequency) and will look at getting an analyser card, assuming I exhaust my efforts on the basic checks.

                      There is a 5v STB LED (on). I have measured the 5V STB at the 24 pin power connector, and this 5V can be seen on a MOSFET near the 5V STB LED. I guess that this 5V will be used by the RTC at some point.

                      The history of the system suggests it just stopped working, and nothing was done to address this, the system was just replaced. As it was a "manufactured" system, all wires are neatly routed and cable tied in place, which is how it was when I got it.

                      Comment


                        #12
                        Re: Intel DQ45CB No Boot

                        Do you know what other pre-requisites there are for MB startup? I don't know if the BIOS could be corrupted. from what I have read, it is possible, and the only way to recover is to de-solder the SPI chip and re-flash on the bench using an appropriate programmer.
                        IS the BIOS controlled by the RTC chip, or does that just do clock time?

                        Comment


                          #13
                          Re: Intel DQ45CB No Boot

                          Hi Russ
                          It's good to see you have some test equipment available. I was going to ask you if you knew the history of this motherboard, so thanks for that information

                          So you have tested this motherboard using the CPU and RAM form the other one, and basically one boots, the other powers on but doesn't boot?

                          I had a look for a boardview of this motherboard and I couldn't find one - unless it has some other model number on it, it could be worth you looking.

                          So we are going to have to work from component datasheets. Can you post some pics of the motherboard here please. maybe one pic of the whole board and a few close ups of each area.

                          The next thing I would be looking for is the SIO - what is the part number, can we find a datasheet?

                          Can you identify any USB controllers and again the datasheet?

                          Can you identify the LAN controller and find datasheet?

                          Sometimes a short circuit on the LAN controller or USB controller will stop a board from booting, and as these chips are effectively connected to ports where people can plug things in, they are more likely to be damaged. Also look for damaged USB connectors and LAN conectors.

                          Regards BIOS yes, I've seen that - a corrupted BIOS stops the motherboard from booting. I've also seen a BIOS of too early revision to support the current processor will cause the same symptoms. The latter you can generally find the BIOS revisions and processor support by googling.

                          You are correct - you often have to unsolder the BIOS and program it externally using a suitable programmer. I have the TL866 and found it very easy to use, even for a novice - basically an Eprom programmer is pretty much essential for anyone repairing motherboards.

                          There are various ones available - some very cheap - have a look which BIOS chip you have, then you can ask in the relevant section of the forum

                          I do recommend this one myself.
                          https://es.aliexpress.com/item/33044...caAuHzEALw_wcB

                          Another thing I would look for is LDO voltage regulators and Buck regulators - try to identify all the ones on your motherboard and then check what voltages you see on them. If you find a voltage regulator with input but no output voltage it is worth investigating. Especially if it is getting warm!

                          Once you have the SIO datasheet it is easier to start checking clocks too. There is probably also a clock gen IC - try to identify that too by looking up part numbers and finding the datasheet. It's probably the one very close to a crystal so it should not be hard to find.

                          best regards
                          Rich.
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                            #14
                            Re: Intel DQ45CB No Boot

                            There a couple of crystals on board.

                            32.768KHz (cylindrical type) and a 24.576Mhz

                            The 32Khz crystal measure about 32.5Khz with my DVM, so I will say that is working. Cannot work out which is the RTC chip.

                            Comment


                              #15
                              Re: Intel DQ45CB No Boot

                              Hi Russ. The 32,768 will be for the RTC and this should oscillate even when there is no PSU - it powers from the CMOS battery

                              The 24.576MHz will go to the clock generator and from there it generates all the clock signals for the motherboard, CPU PCI etc. This should be oscillating once power is applied to the motherboard and you turn it on.

                              The RTC will be built in to the SIO

                              Can you post some pics of the motherboard close enough to read the IC markings please.

                              The BIOS should have power, and will be connected to the Southbridge or ICH as they call it.

                              Here is the datasheet for your chipset - there is a block diagram (figure 1) on page 24. That will give you some idea how the parts of the motherboard all connect together
                              Attached Files
                              Last edited by dicky96; 02-11-2021, 08:57 AM.
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                                #16
                                Re: Intel DQ45CB No Boot

                                Dear Rich,

                                Thanks for your continued support.

                                Link to the MB

                                Chipset is Q45 which handles USB/On-board graphics/Memory/SATA

                                https://cdn.badcaps-static.com/pdfs/...ae44b3b8d8.pdf

                                Ethernet is intel wg82567lm

                                https://cdn.badcaps-static.com/pdfs/...a648eb33c6.pdf

                                lsi l-fw3227-400 - Firewire 400 processor

                                similar one

                                Comment


                                  #17
                                  Re: Intel DQ45CB No Boot

                                  Hi Rich

                                  I have taken some pictures, but getting the chip numbers visible is not so easy!

                                  Picture quality may not be great due to having to resize them to upload them.

                                  I have replaced the existing fan with a stock Intel LGA775 fan.

                                  Additionally, when powered on, the MB now wakes up on its own (like the good one does) but doesn't shut down after 5 seconds like the good one does (this situation occurred without any further action on my part.

                                  It just stays "running" with the Intel fan running at "normal" speed now (not full speed like the previous fan was doing).

                                  When system is running, I can command it to go off by holding the power switch for 4 seconds (normal)
                                  I can then power on with the front power switch (by momentary press), but it still doesn't actually boot.

                                  The LED on the mouse lights briefly on power up.

                                  The LAN connection has Green and Orange indicators when connected to a WIFI repeater hub by LAN cable (just to verify the function of the LAN chip)

                                  I have heard three beeps at startup on a few occasions, which according to the Intel website, indicates a Memory Issue.

                                  I have swapped all the memory, but no change - no boot.

                                  I have not taken the CPU or Memory from the other system as I don't want to risk any issues on the working system as it is being used by my son for home schooling.

                                  The CPU was a spare and the Memory I used to swap was taken from the other system as I added some extra memory to that system, so the memory should be OK.

                                  All MOSFETS appear to test OK and voltages on them are "expected" like 5V,12V, 3.3V 1.8V, 1.1V - none are running hot.

                                  May be time to buy a PCI analyser as there seems to be nothing else I can measure as being wrong.

                                  I cannot work out which chip is the BIOS SPI chip - maybe the 8 pin SOIC that is near the graphics slot?

                                  Russ
                                  Attached Files

                                  Comment


                                    #18
                                    Re: Intel DQ45CB No Boot

                                    I can't see the chip numbers either. The BIOS chip will be an 8 pin SOIC probably part number like 25Qxxxx or 28Xxxxx or similar - it may well say Winbond on it but not 100% it will

                                    Really you need to test the CPU and RAM from the other PC in this one (and vice versa)

                                    The chances of damaging the other PC (or the CPU and RAM from it) by swapping parts from this one are next to zero.

                                    There isn't much point progressing further until you do that to eliminate faulty CPU/RAM. Other than that, get a known working (compatible) LGA755 CPU and some RAM from ebay - used will probably cost you about 10 quid in total. Also check the pins in the CPU socket while you are at it. Here is a compatible CPU list

                                    https://www.cpu-upgrade.com/mb-Intel/DQ45CB.html

                                    And they are almost for free - just a couple examples
                                    CPU
                                    https://www.ebay.co.uk/itm/Intel-Cel...UAAOSwp5Bf-9aJ

                                    DDR2 RAM
                                    https://www.ebay.co.uk/itm/4GB-2x-2G...kAAOSwgb5gIZs6


                                    We need to eliminate the obvious first. Let me know when you have done that
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                                      #19
                                      Re: Intel DQ45CB No Boot

                                      Can you please post a picture of the area with your replaced capacitor that dicky96 asked about?
                                      To me it looks like the capacitor next to it is bad from your overview photo.
                                      It is also important that a proper LOW ESR capacitor was used as the replacement.
                                      Originally posted by dicky96 View Post
                                      Hi Russ17
                                      Can you post a picture of the mother board and which capacitor you changed?
                                      "The one who says it cannot be done should never interrupt the one who is doing it."

                                      Comment


                                        #20
                                        Re: Intel DQ45CB No Boot

                                        Hi Per,

                                        Thanks for getting in touch.

                                        The replacement capacitor was salvaged from a TV PSU output stage, so I am hopeful that it is a Low ESR type, but I cannot prove this.
                                        At this point, I was hoping that the faulty capacitor may have been dragging the VCore voltage down, but the replacement capacitor has not changed the voltage, but it was a 1.1V before I started the work, which seems to be about the right voltage to expect.

                                        I attached some pictures (ignore the terrible soldering job).

                                        The capacitor which I replaced was the only bulging one on the whole board, and it not near any heatsink, not even the graphics card which was plugged in near the capacitor, as the heatsink was on the other side of the Graphics Card.

                                        I have yet to use "tested" CPU & RAM components, to rule these out as causes.

                                        In my limited experience, I have only ever seem one bad RAM stick, and that only caused issues when the particular address of RAM which was faulty, was addressed, so the fault was quite random. I have never seen a CPU failure - not that this is impossible, especially of the CPU was overclocked, or under cooled. I know that that this CPU was definitely not overclocked.

                                        The original CPU fan does run full speed, so under cooling is also not a likely cause.
                                        Attached Files

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