Mainboard with No Picture - Page 1
Forum section: electronics / repair

author: 2X
author_rank: Frequent Contributor
timestamp: July 13, 2024, 09:41:59 pm
content: Hi,I have the motherboard W26361-W84-X-02 where it starts the CPU fan but don't show nothing at all. The problem as I saw is that the CPU don’t take a proper voltage. I measured with oscilloscope the voltages on three CPU inductors and the voltage was mVolt and the processor was a bit warm (not hot like a CPU is).I measured the pulses from the 15,18,19 pins of ISL6565BCRZ (Multi-Phase PWM Controller) and looks OK. Also, these pulses arrive at the pin 3 of each ISL6612ECB-T (Advanced Synchronous Rectified Buck MOSFET Driver) respectively.The problem in my opinion is at the output pin 1 that drives the high side mosfet. And in three chips ISL6612ECB-T the pulses are weak and seems like a noise.I checked for shorts but I didn't find anything and I replace the electrolytic caps.Also, I tried the below:I replaced the RAM with a same and functional one (from a same second motherboard that I have).I replaced the CPU with a same and functional one (from a same second motherboard that I have).I check the CPU socket for bend pins and all are ok.I have replace the BIOS chip with a same and functional one (from a same second motherboard that I have).I have replaced all the caps in the yellow circles with brand new capacitors.I place a buzzer on the motherboard and no beep even when I remove the RAM.I tried some PCI tester cards and gave me the below codes:The one of them show nothing "--".The second show "0000".The third show "FF".As I saw in a "PC Analyzer Users Guide" pdf that I found on the internet:The "00" means "Code copyng to specific areas is done. Passing control to INT 19h boot loader next.The "FF" means "Flash ROM programming was succesful. Next restarting the system BIOS."Do you know what these codes means in practical level?Datasheets:https://www.renesas.com/us/en/document/dst/isl6612-isl6613-datasheet(ISL6612, ISL6613)https://www.mouser.com/datasheet/2/698/intersil_fn9135-1277737.pdf(ISL6565A, ISL6565B)https://dimm.me/wp-content/uploads/PC_Analyser_Instructions_PCI_ESA_Card_FINAL_OCR-libre.pdfP.S. I can’t through the motherboard in the bin because it is from an old machine and unfortunately works only with this motherboard with any other similar

author: indeterminate
author_rank: Regular Contributor
timestamp: July 14, 2024, 09:35:54 am
content: Connect a speaker to the boardif there is any life in the board you should be able to hear sum beep codesif no beep codes then look up the voltage requirements for the cpuand use a meter to find out witch supply is faulty.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 14, 2024, 10:42:41 am
content: ok you have posted elsewhwere too i thinkand this board is a Fujitsu Siemens FSC D1837-A21 W26361-W84-X-02 ATX Mainboard Sockel/Socket LGA775 Intel 915 chipset,you should be able to substitue it, unless you have very specialized software and or markers who will block from workingyou may have gone too far changing all the capacitors.. normally you do the ones in the cpu power section, theses fails oftenwhat caps have you put in there, low esr ones ? standard ones, high temps ... and the correct orientation ?have you tried the psu and forced the psu to start, you have many infos on how to and atx pinouts ... voltage on the 4 pins cpu power plug, and voltages on the main plug ?https://theretroweb.com/motherboards/s/fujitsu-siemens-d1837

author: 2X
author_rank: Frequent Contributor
timestamp: July 14, 2024, 11:32:38 am
content: Quote from: coromonadalix on July 14, 2024, 10:42:41 amQuoteunfortunately I can't replace it because have very specialized software.QuoteI placed new nichicon and panasonic Low ESR capacitors and I placed them with the right orientation/polarity.QuoteSorry but I don't now what do you mean with the "tried the psu and forced the psu to start"This that I did is to jumper the pins "Power ON-OFF" instantaneously and the PSU start ok (I also tried another PSU) and the voltage on the 4 pins cpu power plug is 12V and on ATX connector there is the voltages 3.3V, 5V & 12V and the pins that they should be (I will check a them again and I will post them).Thanks for your time and your detailed reply.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 14, 2024, 12:57:12 pm
content: atx psu's can be forced to start you need to tie a wire to ground, check on the web atx pinouts, normally it's the green wire if i recall. and to help regulations sometimes, i put a defective hdd just to create some current drawclear the motherbaord cmos, sometimes it can help, as other wrote, if you dont get beeps post codes, the trouble may be harder than you think, the cpu section could be dead ... and sadly the motherboard is toastedthe post codes are not fully universal, you need the ones for you bios brand phoenix, award etc ....as for specialized software what it is ? pick and place .. security ... usb dongle keys, hardware id's, you can at least say something .. unless from the start something is fishy ...you should try to find intel 915G based chipsets motherboards .... some are very cheapand you talk about a second motherboard does it suffer the same problems ?

author: 2X
author_rank: Frequent Contributor
timestamp: July 14, 2024, 02:08:24 pm
content: Quote from: coromonadalix on July 14, 2024, 12:57:12 pmQuoteThe machine is a CNC laser router that was made from a company that don't exist anymore (company name atlas... the customer of the machine told me that)QuoteNo this motherboard works fine.The customer of the machine has given me four same motherboards (from same exactly machine models) where all have the same problem (CPU fan spins and no image) except from one motherboard that works perfect.I will make some more tests and I give you feedback.Thanks again for your time.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 14, 2024, 11:41:55 pm
content: please post pictures of the pcb's

author: Psi
author_rank: Super Contributor
timestamp: July 15, 2024, 01:37:08 am
content: Quote from: coromonadalix on July 14, 2024, 11:41:55 pmdid you read the topic?"Mainboard with No Picture"

author: fzabkar
author_rank: Super Contributor
timestamp: July 15, 2024, 02:35:07 am
content: Your datasheet links are broken.https://www.renesas.com/us/en/document/dst/isl6612-isl6613-datasheet(ISL6612, ISL6613)https://www.mouser.com/datasheet/2/698/intersil_fn9135-1277737.pdf(ISL6565A, ISL6565B)What voltage do you measure at the REF pin of the ISL6565BCRZ? Are the VID pins all 1s (Vcore regulator switched off)

author: 2X
author_rank: Frequent Contributor
timestamp: July 16, 2024, 06:57:40 pm
content: Quote from: fzabkar on July 15, 2024, 02:35:07 amQuoteThanks... I replaced the links.QuoteI measured all the pins from the ISL6565BCR (at the attached image). The ISL6565BCR have ENable signal but but the voltage at REF pin is zero.QuoteSorry but I didn't understand what do you mean with "Are the VID pins all1s"Thanks for your time and the suggestions.P.S. One thing that I noticed at the faulty mainboard is (with no CPU fan) when I switch ON the PSU I hear a buzzing with a very low volume (like whisper) around the CPU.

author: fzabkar
author_rank: Super Contributor
timestamp: July 16, 2024, 07:29:52 pm
content: Look at page 14 of the datasheet.VID4 - VID0, VID12.5 --> 101001 --> Vcore = 1.350VVID4 - VID0, VID12.5 --> 010101 --> Vcore = 1.600VThis means that the REF voltage should be 1.35V for the working motherboard, and 1.600V for the faulty motherboard. Instead it is 0V. When the Vcore regulator is functioning properly, the feedback voltage (FB) should match the reference voltage (REF).Is it possible that the REF pin is shorted to ground, perhaps via the bypass capacitor???Edit:The datasheet states that the REF output of the DAC has a 1K series resistor. Could it be that the chipset is pulling this pin to ground and disabling the Vcore regulator???

author: 2X
author_rank: Frequent Contributor
timestamp: July 17, 2024, 08:12:23 pm
content: Quote from: fzabkar on July 16, 2024, 07:29:52 pmQuoteI check the capacitor in REF pin and it was OK. I measured it in diode mode and it was 0.73V (0.74V in the working mainboard) and the capacitor (desoldered) is 22nF like in the working mainboard. Also, I disconnect completely the capacitor and did't work, I cut the trace before the the via and didn't work again (attached picture - at the image the capacitor is missing because I took the photo when I have desoldered it).QuoteThis 1K resistor is connected between REF pin and at the inputs of two amplifiers via two other "voltage multipliers". There is the possibillity internal the chip to have a short? I measured all the pins in diode mode with the multimeter and all the pins show me the same Volt except from the pin 5 (VID12.5) where it shows me 0.65V in all the faulty mainboards and 0.32V in the working one.

author: fzabkar
author_rank: Super Contributor
timestamp: July 17, 2024, 08:54:47 pm
content: I can't see any alternative other than replacing that IC. It seems like a strange fault, though. :-?

author: 2X
author_rank: Frequent Contributor
timestamp: August 13, 2024, 09:44:40 pm
content: Hi,I replaced the ISL6565BCRZ chip but the same thing again and all the voltages at the ISL6565BCRZ pins are the same. It is something that keep the outputs down. Do you beleive that If the problem is from current sense and if I disconnect the resistors that are for Isense (ISL6565BCRZ picture in red circle) maybe will work? Maybe the problem is on the mosfets or the mosfet drivers that are after the ISL6565BCRZ?According to the block diagram of ISL6565BCRZ if I understand it right... the only stage that can disable the "DYNAMIC VID" is the "SOFT START AND FAULT LOGIC" and this can be triggered via OVP, ENLL and EN pins, so maybe the problem is at these pins somehow? The strange is tha the voltages are the same these pins with the working one mainboard (picture Voltages).From ISL6565BCRZ datasheet:EN - This pin is a threshold-sensitive enable input for the controller. Connecting the 12V supply to EN through an appropriate resistor divider provides a means to synchronize power-up of the controller and the MOSFET driver ICs.When EN is driven above 1.31V, the ISL6565A, ISL6565B is active depending on status of ENLL, the internal POR, and pending fault states. Driving EN below 1.14V will clear all fault states and prime the ISL6565A, ISL6565B to soft-start when re-enabled.ENLL - This pin is a logic-level enable input for the controller. When asserted to a logic high, the ISL6565 is active depending on status of EN, the internal POR, VID inputs and pending fault states. Deasserting ENLL will clear all fault states and prime the ISL6565A, ISL6565B to softstart when re-enabled.OVP - Overvoltage protection pin. This is an open drain device, which can be externally configured with a resistor to control an SCR to shut down the regulator.

author: 2X
author_rank: Frequent Contributor
timestamp: August 16, 2024, 06:20:15 pm
content: Hi,I made some more measurements with oscilloscope. I read on the datasheet that "It is important that the driver ICs reach their POR level before the ISL6565A, ISL6565B becomes enabled.", so I measure the VCC of ISL6565B in respect to ISL6613 in the working and faulty matherbord and the only defference that I saw was a spike in the faulty one.Also, the PGOOD (in the faulty one is zero and in working one is ~5V) can be affect by pins EN, ENLL, POR, or one of the no-CPU VID codes "PGOOD only transitions low when an undervoltage condition is detected or the controller is disabled by a reset from EN, ENLL, POR, or one of the no-CPU VID codes.". I measured also this with oscilloscope but I didn't saw something.I measure also the I sense pin but I didn't pulse that will declare a short.What do you beleive can stop the phase controller from giving PWM pulses?Also a weird thing for me is that I use a thermal camera and the CPU has temp around 50Celcius (after 2 mins approximattely)... how the CPU can have a temperature like this without the ISL6565B not working?

author: 2X
author_rank: Frequent Contributor
timestamp: August 16, 2024, 06:21:20 pm
content: The rest images.

author: 2X
author_rank: Frequent Contributor
timestamp: August 18, 2024, 08:25:11 am
content: Does anyone knows if there is a aschematic for this motherboard or at least a schematic diagram for a similar model?

author: 2X
author_rank: Frequent Contributor
timestamp: August 18, 2024, 08:31:52 am
content: I thought to make an experiment... to remove the CPU and give with an external power supply the 12 V and the VID voltages (VID4 - VID0, VID12.5 --> 010101 --> Vcore = 1.600V) on the ISL6565B and attach a resistor of 4.7ohm at one of the coils so to check if the ISL6565B will work. Do you beleive it is worth or will make any further damage on the motherboard?

author: Haenk
author_rank: Super Contributor
timestamp: August 18, 2024, 08:51:17 am
content: Did you check the solid caps? I noticed you did not replace those. These do have a limited lifespan as well; if in commercial 24/7 use over a decade, you might have reached the end of the lifespan.Is your software bound to the BIOS? I'm really convinced a whole replacement computer might be the way to go, FSC sold a zillion of computers in Germany, might want to check ebay or kleinanzeigen.de

author: GGMM
author_rank: Frequent Contributor
timestamp: August 18, 2024, 09:06:14 am
content: Hello,here a link on site retroweb for this motherboardhttps://theretroweb.com/motherboards/s/fujitsu-siemens-d1837Interesting, I have the same phenomenon on my Atlas 757. That’s what happens on the display. Only 00-FFCurious to know the solution.cdt

author: Haenk
author_rank: Super Contributor
timestamp: August 18, 2024, 09:07:36 am
content: This looks like an option to me:https://www.ebay.de/itm/325351609103Though not cheap, but cheaper than all the working time already invested. Might need to check for exact mainboard part number...

author: 2X
author_rank: Frequent Contributor
timestamp: August 18, 2024, 09:07:43 am
content: Quote from: Haenk on August 18, 2024, 08:51:17 amThanks for your reply... What do you mean by solid caps... you mean the ceramic SMD capacitors (MLCC) or the aluminum ones with red lines around the CPU (those I changed too)?Because, every problem give you a knew knowledge I don't want to give up.

author: GGMM
author_rank: Frequent Contributor
timestamp: August 18, 2024, 09:12:59 am
content: re,Stupid question, there is no battery on your motherboard picture. Normal?Because I dig on the side of memory cmos...for my atlas motherboardFor info only, i think you have put a good batterycdt

author: 2X
author_rank: Frequent Contributor
timestamp: August 18, 2024, 09:17:24 am
content: Quote from: GGMM on August 18, 2024, 09:12:59 amI put a brand new panasonic battery and the same issue. Indeed I have noticed also in some old motheboards that if the CMOS battery is low don't start normally.

author: GGMM
author_rank: Frequent Contributor
timestamp: August 18, 2024, 04:07:56 pm
content: 2x,I watched this video.Without claiming that there is a solution to the problem, it indicates an interesting site, where you can find motherboard schematics.https://discord.gg/vam6YC8vwUThere are not all models, but it can helpcdt

author: 2X
author_rank: Frequent Contributor
timestamp: August 25, 2024, 10:38:36 am
content: First, I tried to turn on the motherboard without CPU. I cut the VID0 trace (before the via) and I connected to GND, so VID4-VID0-VID12.5 combination was “111101” -> Vcore=1.1V (according to table of the page 14).The result was that now I had the correct voltage on the REF pin (1.1V) but still no PWM pulses on pins PWM1, PWM2, PWM3 (I measured all the voltages on the ISL6565 pins (image 1).Second, I recreate a PWM signal exactly that I saw on the good one mainboard on the PWM3 pin of ISL6565. Then I drive the PWM pin of the ISL6613 with this PWM signal from a function generator (images 2,3) and the the PWM signal from the function generator was sinking. I measured the two other ISL6613 and the UGATE pins and LGATE pins had at UGATE 12.5V (in respect to ground) & LGATE 10.57V. Then I desoldered only the PWM pins of these two mosfet drivers and the signal from the function generator was OK and the step-down circuit worked (images 4,5,6) so the problem I believe is in the circuit before the mosfet drivers.Below (image 6) I tried to make an analysis of the ISL6565 block diagram in order to understand what is this that prevents the PWM pulses to start at the PWM outputs even now (with CPU out) where I have the correct REF voltage (1.1V).*VDIFF output is the VSEN input multipied x1.*UVP comparator’s output is: (+In + 200mV) > VDIFF -> Vout=1 (High level)For Good Mainboard: (1.34+0.2V) > 1.3V -> Vout=1FMWNCPU: Faulty Mainboard With no CPUFor FMWNCPU Mainboard: (1.09+0.2V) < 2.55V -> Vout=0*PGOOD output (is an indication of the end of soft-start) is the true table of NOR gate where “A” input is the output of the UVP comparator and “B” input is the output of the “SOFT-START AND FAULT LOGIC”.For Good Mainboard: A&B must be “0” in order the output will be high (0.49V – from the datasheet table at page 9… PGOOD Max low voltage=0.4V).But the output of the UVP comparator I have calculated/assumed it “1”, so what am I missing here?COMP – E/A(Error Amplifier) output is:(+IN=REF) > FB -> Vout=0(+IN=REF) < FB -> Vout=1For Good Mainboard: 1.34V < 1.35V -> Vout=0 (the difference between two values seems to me very small)For FMWNCPU Mainboard: 1.09 < 2.65V -> Vout=0VThe E/A comparator (gives “1” or “0” when all are OK?... how can I sure for this?FB input is a negative current proportional to output current II can’t tell what is this exactly… maybe an analogy would be for instance 1uA on FB pin will corresponds to 1A on the “uP LOAD” (page 6)The Greek Sigma symbol in the circles (like the brown line on the comp pin) is an adder? How it works with digital logic “1” & “0”… or maybe the inputs of the adder are in analog and not in digital values.Output of the AND gate at the “SOFT-START AND FAULT LOGIC” as I understand must be “1” in order the soft start will activate when the power/VCC will apply on the chip. In order the AND gate output will be “1” the VCC must have 5V, the ENLL must have 0.8V and above (table – page 6) and the comparator with hysteresis must have a voltage above of 1.24V at the non-inverting input (EN pin), in order to give “1”.The function of the OFS pin is not clear to me and also, I doubt if it is input or output).Could anyone confirm or correct what I wrote above?ICOMMON pin: When I touch this pin with the multimeter’s probe or with oscilloscope probe in order to measure the voltage on it the mainboards (Good & Faulty) shutdown).I managed to measure the voltage of this pin with an x100 oscilloscope’s probe (imageat the fault mainboard and it was 1.26V and on the Good one was 1.25V.When I desoldered the resistor from the ICOMMON pin (image 13) the CPU coils then start to have 1.57V and the REF pin of ISL6565 1.57V. When I resoldered this resistor back in place the CPU again have 1.55V and the REF pin of ISL6565 1.57V. Maybe the problem of the not working ISL6565 was a cold solder joint?The current from the BIOS battery is 0,54uA (in the faulty one).The problem now is that still the mainboard doesn’t have image and when I remove the RAM the speaker doesn’t make any sound at all. I found the below (image 9) of a power sequence from the video that the “fsasdad” suggest me. Also, I checked with the oscilloscope the xtal of the chip (image 10) and I saw a signal so it has a clock. Any suggestions of what to check?

author: 2X
author_rank: Frequent Contributor
timestamp: August 25, 2024, 10:39:58 am
content: The modifications that I made with a different VID code.

author: dzonika9661
author_rank: Newbie
timestamp: August 27, 2024, 08:40:03 am
content: Hey buddy i'm from discord LER group,Does your pch and cpu heats up on your motherboard ?we can eliminate the bios chip/firmware from the list of possible faulty components

author: 2X
author_rank: Frequent Contributor
timestamp: September 07, 2024, 06:12:42 pm
content: Quote from: dzonika9661 on August 27, 2024, 08:40:03 amHello,I took a photo from the motherboard and the PCH temp is around 50celcius. Also, the motherboard heats (the voltage on CPU coils is 1.55V).Any suggestions of what other to check?

author: dzonika9661
author_rank: Newbie
timestamp: September 07, 2024, 06:57:52 pm
content: Good 50C is not high temp so we know now that PCH is getting power.Did you check all the mosfets for required voltages 3V,5V,12V ?Can you turn on and turn off your motherboard by power button ?

author: 2X
author_rank: Frequent Contributor
timestamp: September 07, 2024, 07:04:02 pm
content: Quote from: dzonika9661 on September 07, 2024, 06:57:52 pmMany thanks for your reply. I have measure voltages 3V,5V,12V on the motherboard. Could you tell me what mosfets or where you would like to check for these voltages on the below picture?

author: dzonika9661
author_rank: Newbie
timestamp: September 07, 2024, 07:20:28 pm
content: Since there are no PWM pulses the problem can be in pwm controller area or the PWM controller itself ( ISL6565 )

author: 2X
author_rank: Frequent Contributor
timestamp: September 07, 2024, 07:26:08 pm
content: Quote from: dzonika9661 on September 07, 2024, 07:20:28 pmThanks for your reply. In my previous post I wrote how I solved the problem of PWM pulses. Please read below.Quote from: 2X on August 25, 2024, 10:38:36 am

author: dzonika9661
author_rank: Newbie
timestamp: September 07, 2024, 07:42:07 pm
content: Yes i see now

author: dzonika9661
author_rank: Newbie
timestamp: September 07, 2024, 07:47:24 pm
content: Check these mosfets marked in X symbol on pictureIf you have oscilloscope check if crystals are working within rated frequency

author: 2X
author_rank: Frequent Contributor
timestamp: September 15, 2024, 12:40:28 pm
content: Quote from: dzonika9661 on September 07, 2024, 07:47:24 pmHello,I measured all the voltages from the working and from the faulty maniboard. Only at the mosfets of the CPU I found some differences.