VOGONS


First post, by Roland30

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Hello , i have a FIC PA-2013 motherboard , i wanted to put in a new system, the board was working fine for 30 minutes , after that it started freezing and had to restart to make it work, and made a squeeking noise at the cpu capacitors ( the small SMD capacitors in the middle of the socket )
Now the motherboard wont post at all ...

So basically i identified a mostfet that is really hot, near the battery , its a 9435A -30V P-Channel Enhancement Mode MOSFET.
I uploaded 2 pictures where the hot mosfet is .

What i've done :

Replaced the mosfet with a new one , replaced it again with a new one ( just in case )
Recapped all main capacitors with new ones.
Checked for any short ( ive checked all small smd capacitors , none of them are in short )
Replaced 3 cpu-s
Tried with 2 power suplies
Tried with at least 10 memories
Cleaned the board
North bridge and South bridge look good because i cannot identify any short.
Checked the 2 VRM-S near the CPU , not in short .
Removed all main capacitors like 13 of them and started the board without them ( mosfet still getting hot )
And yes the jumper settings for the cpu are okay.
Checked for any dirt between ( Sdram slots , agp , pci )

So basically i dont have any more ideeas, i will try to start the board tomorrow without the bios chip , and see if mosfet still getting hot , if it wont maybe some problem within the bios chip ? i have a programmer so i can make another bios chip.
Anybody can come up with some ideeas , because i have kinda ran out of them 😀

Come lets ressurect this board , its one of the best motherboards out there if not THE BEST for super socket 7 , it would be a shame for it to die 😀

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Reply 1 of 15, by synrgy87

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Have my FIC VA503+ died in a similar fashion to this I've not been able to get it back up and running again, the failed mosfet could have taken something else out if that's what's failed, although I wasn't able to identify any other shorts or failed components, Could be something SMD. or a dead VIA chip(hopefully not).

Reply 2 of 15, by Roland30

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Oh so i am not alone , i am trying everything i can to make this board up and running again 🙁
I dont think its the chipset , because all components near them are not in short , usually when the chipset dies there are a lot of capacitors (smd) near that are in short.
Oh and also when i start up the board the cpu gets normaly hot ( its getting its default temperatures without a heatsink)

Reply 3 of 15, by verysaving

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The mosfet you replaced, the ic controller near it, the diode,
the coil and the electrolytic capacitor forms a DC-DC converter
that should supply some chips on the board.
You need to check (or replace) the diode and the controller that
drives the mosfet.

This is the datasheet of the controller :

https://www.onsemi.com/pub/Collateral/CS51031-D.PDF

the typical application diagram in figure 1 should give you
an idea of how it works.

Keep in mind that usually a mosfet blows because of an overload,
so most likely, something powered by the mosfet failed short
(or very low resistance) and caused it to blow.

Reply 4 of 15, by Horun

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Roland30 wrote on 2020-11-30, 23:59:
Hello , i have a FIC PA-2013 motherboard , i wanted to put in a new system, the board was working fine for 30 minutes , after th […]
Show full quote

Hello , i have a FIC PA-2013 motherboard , i wanted to put in a new system, the board was working fine for 30 minutes , after that it started freezing and had to restart to make it work, and made a squeeking noise at the cpu capacitors ( the small SMD capacitors in the middle of the socket )
Now the motherboard wont post at all ...

So basically i identified a mostfet that is really hot, near the battery , its a 9435A -30V P-Channel Enhancement Mode MOSFET.
I uploaded 2 pictures where the hot mosfet is .

Appears that is for the AGP slot. The CPU Mosfets and circuit are near the cpu socket.
You never mention what video card you are using. Does that 'red circled' mosfet get hot when using a PCI card ?
Hard to believe a Mosfet that can handle 5amps does not have a heatsink tab. The PDF says it runs up to 125C on a minimum pad, which it is, and that is very hot !

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor.

Reply 5 of 15, by LeFlash

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Mosfets tend to run hotter when the driving signal gets weak.
Then they are in a state between open and short, converting energy to heat.
Best would be to check the gate with an oscilloscope, second best is to just change the controller and diode.

Reply 6 of 15, by Roland30

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Thank you for the quick reply , the diode seems fine when checked in continuity mode on the multimeter , the 51031 its cold when i touch it .
Should i try to replace first the diode , and if its still getting hot , replace the 51031 ic ?

Reply 7 of 15, by Roland30

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Hello all again , i replaced the 9435A also the 51031 ic and the diode , replaced all 3 components , now its not geting hot but still no image , cpu is cold ...
A thing i forgot to mention , that when it worked ( last minutes ) the cpu fan suddenly stopped working and turning fan on an off , and then the fan just stopped , the Cpu fan connector didnt give 12V anymore , and after that when the cpu fan was not working everything froze and the board died ...

Anyone got an ideaa what could it be ?

Reply 9 of 15, by Roland30

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Update : i replaced the 3 components again , and the cpu is geting hot like normal , but the ic is getting verry hot ( 9435A ) , dont know what to do anymore , why is that ic geting hot ? i replaced it with a second new one ...

Reply 11 of 15, by Roland30

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pentiumspeed wrote on 2021-02-12, 02:07:

Are you getting components from china? They're fakes.

Cheers,

Yes i did get them from china , i got a lot of components from china , and never had any issue , i measured the diode the new one with the old one , and its the same value , about the 2 ic-s i cant tell if fake or not , but tried changing 3 times and it does the same .

Reply 12 of 15, by pentiumspeed

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Yes, fakes, guaranteed especially electronic components. Few times I got simple electronic components and they were fakes, this happens when every time with chinese origin. I bought anything else from other sellers that are not China in origin, I got good parts. The worst I ever seen in my life was amplifier IC for one project, the leads is like crumble cake that crumbled when bent and IC did not work at all: oscilloscope showed extremely distorted signals and weak.

The recent one in (2020) was 40pin SOJ memory chips for video cards from china, and was fakes, black paint over original and remarked, and the leads would and will *NOT* take solder at all, EVEN sanded cleaned!
Now I'm shy of china except for rare items when I need to do some trials, once I know how things works out. I build my own from non-chinese origins as they cost bit more.

And I no longer deal with chinese for anything else except crystals or assembled boards (rarely). One time chinese did not ask me if I wanted money or show me different crystal *first* before sending out (important! ask customer first!), because one order they shattered quartz crystal and just sent me substitute with a email letting me know after the fact, and it was way off from what I was supposed to get. Luckily it was cheap purchase but still.

Luckily you can substitute the components by checking with datasheet and substitute them, these works well. Plenty of good sellers with good prices take your time to find them.

I just placed a large order of 38 canadian shipping included, of about 8 components all in lots for my home made adjustable PWM signal controllers to run fans from a canadian seller I found.

Cheers,

Great Northern aka Canada.

Reply 13 of 15, by Roland30

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verysaving wrote on 2020-12-01, 01:54:
The mosfet you replaced, the ic controller near it, the diode, the coil and the electrolytic capacitor forms a DC-DC converter […]
Show full quote

The mosfet you replaced, the ic controller near it, the diode,
the coil and the electrolytic capacitor forms a DC-DC converter
that should supply some chips on the board.
You need to check (or replace) the diode and the controller that
drives the mosfet.

This is the datasheet of the controller :

https://www.onsemi.com/pub/Collateral/CS51031-D.PDF

the typical application diagram in figure 1 should give you
an idea of how it works.

Keep in mind that usually a mosfet blows because of an overload,
so most likely, something powered by the mosfet failed short
(or very low resistance) and caused it to blow.

I`ve replaced the 2 chips and the diode , still that ic is geting hot , any other sugdestions ?

Reply 14 of 15, by pentiumspeed

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You have to sod the fakes and buy electronic components from non-chinese sellers and rebuild the VRM section in one go. Does not matter if you keep using the parts from chinese.

Cheers,

Great Northern aka Canada.

Reply 15 of 15, by Roland30

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pentiumspeed wrote on 2021-02-13, 22:08:

You have to sod the fakes and buy electronic components from non-chinese sellers and rebuild the VRM section in one go. Does not matter if you keep using the parts from chinese.

Cheers,

Ok so i will buy the 2 ic-s from a trusted source , also the diode , and i will re change the 3 components , another thing , if i take the cpu out , the ic is not getting hot ...
I will post as soon as they will arrive !