Listen to this.... i think my F-USB is BUST!!!!

[stevo1210]

Hey there,

Well i had a mishap happen to my beloved and newly recapped PC Partner V845SX motherboard on Sunday after noon.

Well this is how the story goes....

I took this computer to a shop in Fairfield (yes i actually took it to a proper computer store) well i asked them to plug in the Front USB cabling into the motherboard since i had just bought a new case and needed them to connect it, well they read the instruction manual for it and then plugged in my USB connection cable, then they turned it on, it didnt work! there was no power. Then "the technician" did something which im not sure of and smoke came out of my PC.... my heart just fell when i saw smoke and smelt burning from my case.

I think "the technician" probably tried and somehow mixed the ground and VCC (+5V power) up by twisting the connector the other way!!!!

FLASHBACK STORY:
i know this since i tried it on my PC Chips m550 Pentium 1 board a few years back and the after effect was not good, though the board did turn on and worked until a smart technician (not me, a friend) decided to take ram out while the computer was on, then forcing the SIMMs back in and completely destroying the slots.

Back to the main story now....

Well the odd thing is that i took the whole board out and inspected it closely and i cant find any burn marks ????!!!! and rear USB, PS2 ports all work fine.... amazing!


Im just wondering if i should sue this guy if (NOTE: IF) i find any damage on my beloved board!!

Sure i may only 16 years old, but i definitely know that smoke coming from a motherboard is NOT good after 5 years of hardware experience and 2 years with miniature electronics. But i think i have the right to sue someone if they damage something of mine.... i wanted the USB issue fixed not destroyed!!

Well at least he didnt charge me for it which was kinda relief. Though i did spend a few minutes arguing with him but he seemed to say that it happened for a few seconds and no harm done because the board still boots fine. (Not sure on the "no damage" part though since my Father, Me and "the technician" all saw smoke!! we even smelt it.)


Anyone got any ideas to what may have been damaged? I cant find the damage!!!! must i be blind or something? I cant smell the stench so theres no use for smell here.


Thank You

[stevo1210]

Re: Listen to this.... i think my F-USB is BUST!!!!

I forgot to add....

The cable fine, the USB fired up well in another PC and i used my Mouse and K/B in the ports for a while so its OK.

[pentium]

Re: Listen to this.... i think my F-USB is BUST!!!!

This is very odd. Check your cabling for burned insulation.
There is no such thing as phantom smoke.

[stretch0069]

Re: Listen to this.... i think my F-USB is BUST!!!!

my first thought is power supply. i would think that if anything smoked on the mobo, you'd see it....but i have been known to be wrong before.

i've even seen PSUs that have let some of their smoke out and would still work, albeit not very well.

[ifrythings]

Re: Listen to this.... i think my F-USB is BUST!!!!

Can you post a high(ish) res pic of the usb area, this way I can assist you by showing you what parts maybe damage.

Also check here for the different types of fuses on mobo's that can die and posibly smoke.

PS, check to see that you have 5V and a ground connection at that header, I betting on the missing 5V line there.

[gonzo0815]

Re: Listen to this.... i think my F-USB is BUST!!!!

I have shorted an USB header on a K7s5a by my self. It probably burned some traces / fuses i have not found. Any way, i soldered a 5v molex to it. Usually, an USB 5v bus should be shortproof, e.g. by using some polyswich fuses. But ok, on low end boards i would not expect this.

[stevo1210]

Re: Listen to this.... i think my F-USB is BUST!!!! (Pics Inc.)

Ok got some pics, i cant find any burn marks on my board still!!!! I've taken out every single card and inspected them and they havent got burns either.

The USB header is between PCI 1 and PCI 2. I can't smell any burn, those Axial looking things seem to be fine. Ive inspected all the traces and cant find any burnt. The MOSFETS/ Transistors look fine.
No caps are blown or busted though i will order some Samxon caps from here to recap those oversized 12.5mm 3300uf caps up where the VRM is and also recap the whole board, but still those "Licons" look fine for now, the last batch was bulging and leaking too! but i'll replace them all some day.

I've got some more details about my PC now:

*Intel Celeron 2.0A GHz Socket 478
*Achieva Australia/ PC Partner V845SX motherboard w/ VIA P4X266A chipset
*512MB PC133 SDRAM.
*Gigabyte/Nvidia FX5200 AGP 8X graphics card.
*Netgear FA311 Fast ethernet adaptor (REV. B1)
*ESS Teledrive 56K V.92 PCI modem
*Creative DXR-2 DVD ROM

and finally

*52X BTC CD Burner.

[stevo1210]

Re: Listen to this.... i think my F-USB is BUST!!!!

More Pics....

[stevo1210]

Re: Listen to this.... i think my F-USB is BUST!!!!

Forgot to add to items in my PC....

* 30GB Western Digital (WD300) ATA-100 HDD
* 1.44MB Panasonic FDD drive (Not important though)
* 250W Dell Power supply unfortunately i can see Ltec caps in it, but none have bulged.... yet.... (and yes.... i bought this power supply second hand from a shop)

[ifrythings]

Re: Listen to this.... i think my F-USB is BUST!!!!

PS, check to see that you have 5V and a ground connection at that header, I betting on the missing 5V line there.

Please check what I said earlier.

Check the two red circles in the picture attached, with an ohm meter put it on the lowest setting in ohms ex.200 or 1K and check the fuse. It should read 0 or really close too, if it reads really high or nothing, thats what smoked.

[stevo1210]

Re: Listen to this.... i think my F-USB is BUST!!!!

I'm just wondering......

To measure this "fuse" do i have to desolder it first? or just measure it on the board?

[PedroDaGr8]

Re: Listen to this.... i think my F-USB is BUST!!!!

Just on the board

[stevo1210]

Re: Listen to this.... i think my F-USB is BUST!!!!

Ok thanks for the advice,PedroDaGr8 ; i measured both these components still attached to the board with my Micronta Ohmmeter, it was set to 200 on the dial.

So now I've measured the "fuses" on the board and one of them says 0.00 which i guess is OK but the other fuse says 0.01 and refuses to go back to zero? could that one be blown?


Thanks.

[starfury1]

Re: Listen to this.... i think my F-USB is BUST!!!!

Well if you saying it was on the 200 Ohm range and you got those readings then Id say the "fuses" are ok
(I don't know the construction of those components Ifraythings pointed out or how they are likely to fail)

Bottom line is you got smoke from something, so something had a lot of current pass through it causing a lot of heat and is most likely damaged at best or destroyed.

As Pentium said

There is no such thing as phantom smoke.

As above most likely short Vsuppy ground.

Just on fuses....and putting it simply.
They are basically a piece of wire designed to self destruct when too much current passes through them

So they should read Zero 0 ohms if ok (near enough too) and infinite Ohms when blown, or Open circuit

Ideally you should measure components out side of the circuit but since you are looking to see if they are intact it doesn't matter cause they will have 0 ohms or short circuit.
(unless there is something in parallel with it that would have zero or near zero resistance...possible but unlikely)

If they were open circuit or blown then you would be measuring the resistance of something else, which is why ifrythings said high resistance.

If these are fuses inline with Vsuppy rails it might be better to measure each side for the supply rail voltage

Did you check for the voltage as ifrythings said above?

Its a dark pcb by the looks of it, so yeah possible as gono said fried track which may be hard to spot
look for dark or discolored or possibly raise or more smooth looking patch on pcb

[ifrythings]

Re: Listen to this.... i think my F-USB is BUST!!!!

starfury1 - The fuses are very low ohm resistors so anything close to 1 or less is fine for them

adphan50 - The fuses are fine from the values you stated, so next thing is to see if you have 5V on your usb headers. To do this put your black probe on a ground source like the chasie or if it's out of the case, on one of the ground pads of the screw holes.

Next, take your red probe (and have your multimeter set on DC volts and anything around 20V setting) and start checking the ends of the the port terminal.

Here's a pic for reference.

[starfury1]

Re: Listen to this.... i think my F-USB is BUST!!!!

Thanks ifrythings , so they are fusible resistors

[stevo1210]

Re: Listen to this.... i think my F-USB is BUST!!!!

Hello All,

I was at christmas party yesterday and i was talking to an electronics hobbyist. Well i asked him about this USB issue and the fact that i cant find a burn out.... well he told me something that quite scares me.
Since most PCBs are multi layered, could the burnout have resulted in the under layers by any chance?

I'll measure that 5V line when i have time next week.... hopefully next week.

Thank You.

[Shroomie]

Re: Listen to this.... i think my F-USB is BUST!!!!

I've screwed over a motherboard by putting a stick of RAM in partway... Nasty burnt-electronics smell, and it didn't work afterward, but it looked fine.

I assumed that what happened was what you're afraid of.

[ifrythings]

Re: Listen to this.... i think my F-USB is BUST!!!!

It's very unlikley that a inner trace burned out for the usb, the data likes are every low current, the 5V will ride on the top or bottom of the board and the grond is in one of the layers. The ground is very big and would make lots of smoke if it did burn and there would be some kind of noticalbe bulge or black spot.

[ifrythings]

Re: Listen to this.... i think my F-USB is BUST!!!!

I've screwed over a motherboard by putting a stick of RAM in partway... Nasty burnt-electronics smell, and it didn't work afterward, but it looked fine.

I assumed that what happened was what you're afraid of.

Ram put in half way? wouldn't you notic that? then agin people have been able ot put it in backwards.

the burning smell was most likely the northbridge letting go of it;s life.