criz_me wrote on 2023-03-02, 10:39:

Voltages between HIP VCC (pin 28) and VID of the Slotket,

Nope.
I mean
VID0, VID1, VID2, VID3, VID4
(Pins 7, 6, 5, 4 and 3)
VID0-4 are the input pins to the 5-bit DAC. The states of these five pins program the internal voltage reference (DACOUT). The level of DACOUT sets the core converter output voltage (VOUT1). It also sets the core PGOOD and OVP thresholds.

But it doesn't matter, the power supply of the processor core is correct.
Whether it's good or not, just look with an oscilloscope.

PS.
First you need to achieve work with a native slot processor. And only then try Coppermine or Tualatin

PPS
to check, I would apply 3.3V directly from the ATX PSU. Like CUBX-e

@shevalier: see pic attached.

>>PS.First you need to achieve work with a native slot processor. And only then try Coppermine or Tualatin
Understood. I have them at hand and they run well on the other two mainboards.

>>PPS to check, I would apply 3.3V directly from the ATX PSU. Like CUBX-e
I am really struggling to feel confident about desoldering stuff from the mainboard. Also because CUBX-e.jpg is somewhat different. Simply because chances of doing more damage than fixing things are high. I am good with computers / software, just not with soldering small electronics without much experience.

So to make sure I understand: Take out the X'd out coil, and bridge the white line in may_be.jpg?

I have however ordered the parts from https://www.eecis.udel.edu/~portnoi/asusreworkguide.html, and at least I could change the 2sd1802 to RFD3055 and give it a try!

Open to other suggestions of course, thanks!

VTT is producing correct voltage, otherwise CPU wouldnt start at all, but might be bad (sagging/spiking) and crashes cpu early in the boot process. Sadly its all guessing, might as well be dying chipset or cracked track somewhere under dimm sockets.

criz_me wrote on 2023-03-02, 16:47:

just not with soldering small electronics without much experience.

Small - its 0402 SMD.
It`s big, big coil. Dont worry, it`s very simply

Take out the X'd out coil, and bridge the white line in may_be.jpg?

Yes. The other end of the coil is its DC/DC output. But this will only work with an ATX power supply. AT does not have a 3.3V rail.

PS. it may be helpful to replace all blue electrolytic capacitors. They are raised in the photo.
But in this situation, it doesn't.
After opening and closed the case I noticed the PC has frozen

what could cause motherboard to go bad after "opening and closed the case"?
- mechanical, something cracked
- ESD, carpet/sweater?

rasz_pl wrote on 2023-03-02, 17:53:

what could cause motherboard to go bad after "opening and closed the case"?
- mechanical, something cracked
- ESD, carpet/sweater?

mechanical, something moved (like video/sound/lan card) and something shorting

The system froze a few times during the days before, but could always be reset / revived. Until the time it couldnt...I did close the case by the time it happened, so I though it is worth mentioning.

just for kicks try percussive maintenance - push on big chips (south/northbridge) with your finger (moderate force, not enough to bend pcb) and with force applied try starting computer, same with ram/cpu.

rasz_pl wrote on 2023-03-03, 11:05:

just for kicks try percussive maintenance - push on big chips (south/northbridge) with your finger (moderate force, not enough to bend pcb) and with force applied try starting computer, same with ram/cpu.

i am disagree.
This is good old lead solder, not modern lead-free.

criz_me wrote on 2023-03-03, 11:01:

The system froze a few times during the days before, but could always be reset / revived.

recap is may be helpful. Cheap, but good enough, polymer samwha FB (8mm dia), like 470u*6.3V
http://www.kosmodrom.com.ua/pdf/samwha-fb.pdf
(Or any analog from Aliexpress. They not expensive for modern use, but for old hardware good enough)
Or use a donor like ASUS M4A785D-M Pro.
They all died anyway. I`ts the asus)))
But they have an old type of polymer capacitors of medium diameter

A brief update: It took a while, since I initially ordered the wrong component. I replaced the 2SD1802 with an "IRFR1205 Transistor N-MOSFET 55V 44A 107W 0,027R". No change so far , still stuck at 00 / 0C...