shevalier wrote on 2025-05-03, 03:54:

if you lucky enough, then just VIO module may burn out

I check both boards with power supply connected, power on. The 'coil' to the left in the image you posted on both boards is similar: .007v. The VIO from left to right is similar: .105v, Ov, 1.26v.

With computer powered on and operating for the working board:
The coil is 3.5v. The VIO from left to right is: 3.5v, 0v, 11.9v.

I have not re-installed the currently non-working board to take measurements with power on and fans operating yet. Based on this info should I continue to proceed with the non-working board to test the coil and VIO?

Still working on the pin-out for the previous cable.

Actually I think you may have been directing I measure voltage at the base of the VIO? The measurement at the base of the working computer with power on and operating is 3.5v. (see image)

Slightly high, but in spec

Your have tried all slots, yes? Sometimes a slot dies.

I'll dig and see if I converted the schematic to kicad

myne wrote on 2025-05-03, 07:01:

Slightly high, but in spec

Your have tried all slots, yes? Sometimes a slot dies.

I'll dig and see if I converted the schematic to kicad

Yes, all memory slots were tried with verified known to be good, operational memory. I have the luxury of having two identical side by side boards.

Attached are voltage readings as read from the connector that attaches to the board, NOT the PSU side. The pinout in the attached image is working well with my other TUV4X board based PC. I made an attempt to verify the pinout of the wire harness that originally kept my system from powering on, but when I went to install the PSU jumper it shorted and reset, so something must be pinned incorrectly in the harness? I was just trying to troubleshoot and discover how much voltage previously went to the 'wrong' place that may have caused my other board to not work?

https://www.chinafix.tech/asus-motherboard-tu … 1-01-boardview/

That'll save you a lot of time

There is no normal photo of TUV4X on the Internet, so I did not notice what is behind the socket.
It must be like this.
I do not know what the ACPI switch defenetly does, theoretically it switches the power from +5V standby (through some regulator) in state S3/5 to +3.3V in state S0.

myne wrote on 2025-05-03, 08:14:

https://www.chinafix.tech/asus-motherboard-tu … 1-01-boardview/

That'll save you a lot of time

Cool, I've been looking for a long time on CUBX

shevalier wrote on 2025-05-03, 08:21:

There is no normal photo of TUV4X on the Internet, so I did not notice what is behind the socket.
It must be like this.
I do not know what the ACPI switch defenetly does, theoretically it switches the power from +5V standby (through some regulator) in state S3/5 to +3.3V in state S0.

Maybe this board image is better.

The easiest way to check is to bypass the VIO regulator, and this is also a factory option on simpler versions on the same PCB.

So, just to make sure I follow. The VIO regulator, if bad, and it appears you are very knowledgeable, could be causing the symptoms I am currently experiencing?

Long beep sequences
Black screen
Board LED light ON with fans operating
CPU warm to the touch

Basically these clues are all I have to go on currently. It's worth a try... Need to break out my soldering iron, think I might have some small gauge solid copper wire as well. So if it works, how is it actually working? You are way above my pay grade! Haha

A dozen things could do it.
What voltage do you see when it's beeping?

myne wrote on 2025-05-03, 12:09:

A dozen things could do it.
What voltage do you see when it's beeping?

This.

The first is voltage measurement. The soldering iron is used much later.

shevalier wrote on 2025-05-03, 12:32:

myne wrote on 2025-05-03, 12:09:

A dozen things could do it.
What voltage do you see when it's beeping?

This.

The first is voltage measurement. The soldering iron is used much later.

I removed the inductor and installed the jumpers, same condition exists.

The voltages are the same with power on the bad board compared to the measurements from the good board as measured at locations in a previous post.

myne wrote on 2025-05-03, 12:09:

A dozen things could do it.
What voltage do you see when it's beeping?

I can check locations, any particular?

One new clue, I removed the BIOS and battery, still powered on the same, but no beeping.

Check this point
1. Vtt for CPU/north_bridge
2. RAM powering

shevalier wrote on 2025-05-03, 13:08:

Check this point
1. Vtt for CPU/north_bridge
2. RAM powering

Vtt=1.24v
The other two points are = 3.31v

Last question, even without measurements.
Does the LED light up in standby mode?

It is powered from this point (the missing capacitor)

shevalier wrote on 2025-05-03, 13:39:

Last question, even without measurements.
Does the LED light up in standby mode?

It is powered from this point (the missing capacitor)

3.4v in standby mode.