Mainboard with No Picture

[2X]

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.pdf


P.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

[indeterminate]

Connect a speaker to the board
if there is any life in the board you should be able to hear sum beep codes

if no beep codes then look up the voltage requirements for the cpu
and use a meter to find out witch supply is faulty.

[coromonadalix]

ok   you have posted elsewhwere too i think

and 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 working


you may have gone too far changing all the capacitors.. normally you do the ones in the cpu power section, theses fails often

what 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

[2X]

ok   you have posted elsewhwere too i think

and 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 working


you may have gone too far changing all the capacitors.. normally you do the ones in the cpu power section, theses fails often

what 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

you should be able to substitue it, unless you have very specialized software and or markers  who will block from working

unfortunately I can't replace it because have very specialized software.

what caps have you put in there,  low esr ones ? standard ones,  high temps ... and the correct orientation ?

I placed new nichicon and panasonic Low ESR capacitors and I placed them with the right orientation/polarity.

have you tried the psu and forced the psu to start,   you have many infos on how to and atx  pinouts ?

Sorry 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.

[coromonadalix]

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 draw

clear 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 toasted

the 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 cheap


and you talk about a second  motherboard   does it suffer the same problems ?

[2X]

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 draw

clear 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 toasted

the 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 cheap


and you talk about a second  motherboard   does it suffer the same problems ?

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 ...

The 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)

and you talk about a second  motherboard   does it suffer the same problems ?

No 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.

[coromonadalix]

please post pictures of the pcb's

[Psi]

please post pictures of the pcb's

did you read the topic?
"Mainboard with No Picture"     

[coromonadalix]

 

[fzabkar]

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)