That's the kind of thing I would suspect of being lightning damage, sorry.

But you did test with the BIOS chip _inserted_ I assume?

majestyk wrote on Yesterday, 09:25:

But you did test with the BIOS chip _inserted_ I assume?

Yes, I just took it out to dump it later.

Could you post a hq pic of the vrm area?
What are the mosfet models?

On a board I have one of the 3 mosfets was dead and Vcore was 1V like.

Nexxen wrote on Yesterday, 14:03:

Could you post a hq pic of the vrm area?
What are the mosfet models?

On a board I have one of the 3 mosfets was dead and Vcore was 1V like.

The buck MOSFET is an FP45N03L and the linear is an RFP3055.

I just replaced the schottky diode and nothing changed.

Hi-FiMan wrote on Yesterday, 19:19:

Nexxen wrote on Yesterday, 14:03:

Could you post a hq pic of the vrm area?
What are the mosfet models?

On a board I have one of the 3 mosfets was dead and Vcore was 1V like.

The buck MOSFET is an FP45N03L and the linear is an RFP3055.

I just replaced the schottky diode and nothing changed.

https://theretroweb.com/motherboards/s/ecs-p5tx-apro

https://www.alldatasheet.com/datasheet-pdf/vi … /RFP45N03L.html

https://www.alldatasheet.com/datasheet-pdf/vi … IL/RFP3055.html

There are 3, what's the other?
One these is having issues, probably if some Vref is present. Or broken.
My guess.

Also the Raytheon is important, https://www.alldatasheet.com/view.jsp?Searchword=RC5034
https://www.alldatasheet.com/datasheet-pdf/vi … EON/RC5033.html
Can't find the 34 model though. It's blurry

Nexxen wrote on Yesterday, 20:01:

https://theretroweb.com/motherboards/s/ecs-p5tx-apro […]
Show full quote

Hi-FiMan wrote on Yesterday, 19:19:

Nexxen wrote on Yesterday, 14:03:

Could you post a hq pic of the vrm area?
What are the mosfet models?

On a board I have one of the 3 mosfets was dead and Vcore was 1V like.

The buck MOSFET is an FP45N03L and the linear is an RFP3055.

I just replaced the schottky diode and nothing changed.

https://theretroweb.com/motherboards/s/ecs-p5tx-apro

https://www.alldatasheet.com/datasheet-pdf/vi … /RFP45N03L.html

https://www.alldatasheet.com/datasheet-pdf/vi … IL/RFP3055.html

There are 3, what's the other?
One these is having issues, probably if some Vref is present. Or broken.
My guess.

Also the Raytheon is important, https://www.alldatasheet.com/view.jsp?Searchword=RC5034
https://www.alldatasheet.com/datasheet-pdf/vi … EON/RC5033.html
Can't find the 34 model though. It's blurry

There's only two MOSFETs and one schottky diode on the VRM. The controller is an RC5036M: https://theretroweb.com/chips/12285.

I removed the FP45N03L from circuit and in diode mode, my meter reads ~500mv source to drain (+ on source and - on drain) and 2.9v and slowly dropping on drain to source. I see a lot of conflicting info on how to properly test an N-channel MOSFET, but I don't think I should be getting 2.9v in reverse.

Hi-FiMan wrote on Yesterday, 20:34:

Nexxen wrote on Yesterday, 20:01:

https://theretroweb.com/motherboards/s/ecs-p5tx-apro […]
Show full quote

Hi-FiMan wrote on Yesterday, 19:19:

The buck MOSFET is an FP45N03L and the linear is an RFP3055.

I just replaced the schottky diode and nothing changed.

https://theretroweb.com/motherboards/s/ecs-p5tx-apro

https://www.alldatasheet.com/datasheet-pdf/vi … /RFP45N03L.html

https://www.alldatasheet.com/datasheet-pdf/vi … IL/RFP3055.html

There are 3, what's the other?
One these is having issues, probably if some Vref is present. Or broken.
My guess.

Also the Raytheon is important, https://www.alldatasheet.com/view.jsp?Searchword=RC5034
https://www.alldatasheet.com/datasheet-pdf/vi … EON/RC5033.html
Can't find the 34 model though. It's blurry

There's only two MOSFETs and one schottky diode on the VRM. The controller is an RC5036M: https://theretroweb.com/chips/12285.

I removed the FP45N03L from circuit and in diode mode, my meter reads ~500mv source to drain (+ on source and - on drain) and 2.9v and slowly dropping on drain to source. I see a lot of conflicting info on how to properly test an N-channel MOSFET, but I don't think I should be getting 2.9v in reverse.

Probably that one is gone.
If you can replace it I'd try that.
Unless someone more knowledgeable says otherwise.

So I just replaced the FP45N03L MOSFET and I'm still getting the same behavior. I really think it's the controller now. How common is it for the VRM controller to go bad?

Well since I reckon it took lightning to telephone wire to external modem to serial port, I think it's quite likely that the VRM and every other piece of silicon on there has problems, but I hope I'm wrong.

I assume you have a multimeter?
Mark some voltages on the picture.

This might help
https://www.scribd.com/document/839113661/Intel-430HX-PCIset

Better yet...
https://schematic-x.blogspot.com/2018/04/more … schematics.html

It won't be identical, but it's unlikely to vary much.

similar Asus TX-97 No Post

but im with BitWrangler , how else would the two happen on one board?
I would unsolder inductors, inject Vcore Vio externally and see if anything is alive

Most certainly that DB9 port took in some lightning. Given that all the passives around that area aren’t fried and measure normally, I’m hoping at least the north/south bridge survived. With that Asus board, it seemed to come down to the same conclusion of a bad VRM controller. Are these controllers unique and do they have any equivalent replacements?

Hi-FiMan wrote on Today, 13:26:

Most certainly that DB9 port took in some lightning. Given that all the passives around that area aren’t fried and measure normally, I’m hoping at least the north/south bridge survived. With that Asus board, it seemed to come down to the same conclusion of a bad VRM controller. Are these controllers unique and do they have any equivalent replacements?

Have measured PSU pins between them and to ground?
The various smd that are used to regulate the Voutput for Vcore / Vio?

Nexxen wrote on Today, 14:01:

Hi-FiMan wrote on Today, 13:26:

Most certainly that DB9 port took in some lightning. Given that all the passives around that area aren’t fried and measure normally, I’m hoping at least the north/south bridge survived. With that Asus board, it seemed to come down to the same conclusion of a bad VRM controller. Are these controllers unique and do they have any equivalent replacements?

Have measured PSU pins between them and to ground?
The various smd that are used to regulate the Voutput for Vcore / Vio?

Yes, all the passives I could measure were OK. The voltage coming off the schottky diode cathode makes it to the socket; it’s just way too low.

Hi-FiMan wrote on Today, 14:33:

Nexxen wrote on Today, 14:01:

Hi-FiMan wrote on Today, 13:26:

Most certainly that DB9 port took in some lightning. Given that all the passives around that area aren’t fried and measure normally, I’m hoping at least the north/south bridge survived. With that Asus board, it seemed to come down to the same conclusion of a bad VRM controller. Are these controllers unique and do they have any equivalent replacements?

Have measured PSU pins between them and to ground?
The various smd that are used to regulate the Voutput for Vcore / Vio?

Yes, all the passives I could measure were OK. The voltage coming off the schottky diode cathode makes it to the socket; it’s just way too low.

You checked the Raytheon network of resistances if correct for V outputs? (correct config)
Vref checks out...
I'm out of easy ideas. I hope it's not a lightning.

Nexxen wrote on Today, 14:41:

You checked the Raytheon network of resistances if correct for V outputs? (correct config) Vref checks out... I'm out of easy id […]
Show full quote

Hi-FiMan wrote on Today, 14:33:

Nexxen wrote on Today, 14:01:

Have measured PSU pins between them and to ground?
The various smd that are used to regulate the Voutput for Vcore / Vio?

Yes, all the passives I could measure were OK. The voltage coming off the schottky diode cathode makes it to the socket; it’s just way too low.

You checked the Raytheon network of resistances if correct for V outputs? (correct config)
Vref checks out...
I'm out of easy ideas. I hope it's not a lightning.

You see that’s the thing, the voltage doesn’t change when I move the vcore jumper. I measured the resistors that the jumper is jumping and they all look good.

Hi-FiMan wrote on Today, 14:55:

Nexxen wrote on Today, 14:41:

You checked the Raytheon network of resistances if correct for V outputs? (correct config) Vref checks out... I'm out of easy id […]
Show full quote

Hi-FiMan wrote on Today, 14:33:

Yes, all the passives I could measure were OK. The voltage coming off the schottky diode cathode makes it to the socket; it’s just way too low.

You checked the Raytheon network of resistances if correct for V outputs? (correct config)
Vref checks out...
I'm out of easy ideas. I hope it's not a lightning.

You see that’s the thing, the voltage doesn’t change when I move the vcore jumper. I measured the resistors that the jumper is jumping and they all look good.

I don't like when boards don't get saved 😀
I was hopeful... Our hobby disappointments, get some lose some.

Nexxen wrote on Today, 14:59:

Hi-FiMan wrote on Today, 14:55:

Nexxen wrote on Today, 14:41:

You checked the Raytheon network of resistances if correct for V outputs? (correct config)
Vref checks out...
I'm out of easy ideas. I hope it's not a lightning.

You see that’s the thing, the voltage doesn’t change when I move the vcore jumper. I measured the resistors that the jumper is jumping and they all look good.

I don't like when boards don't get saved 😀
I was hopeful... Our hobby disappointments, get some lose some.

Yeah I know it… This board was really cheap so it’s not a big deal but getting a decent ATX socket 7 (not even super) is kind of expensive. I just wanted something around the 97/98 timeframe to play with all these PCI cards I’ve got. Maybe I should look into some early slot 1 Pentium II stuff. For now, I’m waiting on a quote from jotrin to see if it’s worth replacing this VRM controller.