GA-8S655FX with very hot FET

[davmax]

Re: GA-8S655FX with very hot FET

Right now this board only boots with a 400/533 Mhz Pentium IV and not with 800Mhz one, but even when boots it locks after a few minutes. I removed all components but the strictly necesary like video card, memory and a cdrom drive to load Ubuntu or to run memtest86.
When boots you can get into BIOS. I have loaded BIOS safe defaults and rebooted to clear a posible BIOS corruption. I tried to load Ubuntu but got locked loading or just after it finished loading without the posibility to check any error or system log.
Im going to try to get a infrared termometer to check this FET temperature and post it here.
I would love to get the SIS 864 datasheet but looked in google with no sucess.

Thanks for your response. So you are using a hard drive. Has it been tested for errors? Errors will certainly cause a freeze installing or running programmes. Memtest should run OK.
PCbonez has flagged a problem with HM caps so it looks like you need a major recap.

[anonbeat]

Re: GA-8S655FX with very hot FET

Thanks for your response. So you are using a hard drive. Has it been tested for errors? Errors will certainly cause a freeze installing or running programmes. Memtest should run OK.
PCbonez has flagged a problem with HM caps so it looks like you need a major recap.

No Im not using any HD at the moment to minimize components. When boot I load Ubuntu or memtest from CD.

[anonbeat]

Re: GA-8S655FX with very hot FET

The FET after about 15mins working (without complete POST) had a temperature of 62ºC
The SouthBridge had 42ºC

[davmax]

Re: GA-8S655FX with very hot FET

I have not used Ubuntu so not familiar. But you say that you are not using a hard drive and checking Ubuntu on Google the CD installer is stated as a very large programme (approx 700Mb) impossible to install and run without a hard drive. It will not run on memory alone and you will certainly freeze the system if you are doing what I understand you to say.

The temperatures you measured are within normal range.

If you have completed Memtest successfully, and this takes some considerable time, this would indicate that memory, processor and power supply are running OK. It does seem that you are freezing the system due to lack of hard drive or problems in that area. Add a hard drive and then try installing Ubuntu.

[davmax]

Re: GA-8S655FX with very hot FET

Re hard drive. If you are not sure about the hard drive use another or download the diagnostic software for that brand. If you cannot get diagnostic and do not have data on the drive that you have not save you need to format the drive, hopefully that will fix any cluster faults. Only another drive will help determine if the controller on the motherboard is faulty.

[anonbeat]

Re: GA-8S655FX with very hot FET

Ubuntu is a Linux distribution that loads from CDROM and uses system memory as a Hard Disk. When not all the CD content can be loaded in memory it uses partial content in memory and partial in CDROM. It should load just fine. The board does not need any HD for complete POST.
Im suspecting this Southbridge is fried

[PCBONEZ]

Re: GA-8S655FX with very hot FET

Ubuntu, because it runs entirely from a CD (no hard drive needed), is often used in trouble shooting to determine if something is a windows drivers problem or an actual hardware problem.
Don't have to remove windows on hard drive.
Just change BIOS to boot from CD first and put in Ubuntu CD.
There is another similar distribution: Knoppix.

.

[PCBONEZ]

Re: GA-8S655FX with very hot FET

Non working USB ports, Sound, LAN are good examples.

[anonbeat]

Re: GA-8S655FX with very hot FET

Problem is that now the board does not POST. It was posting using a 400Mhz Bus CPU but using a 800Mhz Bus CPU does not POST.

I no longer have access to the 400Mhz Bus CPU so now Its not posting.

I used a 1.8Mhz Pentium IV and even could get into the BIOS and load defaults but even in this case it got locked after few minutes.

Using a 3.4Mhz CPU or a 3.2Mhz CPU it does not POST so cant do any test.

I replaced the hotter FET nearest caps with a NH ones I had in other spare board without sucess.

[PCBONEZ]

Re: GA-8S655FX with very hot FET

I will say it one more time:
You need to replace these:
HM 3300uF 6.3v H0411
HM 1500uF 16v H0409
KZG 1500uf 6.3v 39 W(3)

[PCBONEZ]

Re: GA-8S655FX with very hot FET

You should replace any other HM or HN with date codes like
x02xx, x03xx, x04xx

[anonbeat]

Re: GA-8S655FX with very hot FET

Are this Caps good for recapping this board ?

Panasonic [M] FJ 6.3V 1000UF
Rubycon MBZ 6.3V 1500UF
Rubycon MBZ 6.3V 3300UF
Rubycon MBZ 16V 1500UF

Thanks for your help and support

What about the KZG 1000uF 6.3v ? should I replace them also ?

[PCBONEZ]

Re: GA-8S655FX with very hot FET

You replacement choices look good.

Personally I replace all KZG but many people only replace to ones near high heat.
[Like near the CPU, MOSFETs, and sometimes the Video card slot.]

My thinking is that it's less work just to replace a few more caps now when board is on the workbench anyway than to get the board back out and to the workbench again later on.

I'm probably doing more than is needed but it gives me peace of mind.

.

[davmax]

Re: GA-8S655FX with very hot FET

Well I have learnt something about Ubuntu. Did not pick up on the web site the fact that it runs from CD, a non writable device. That is pretty smart running 700Mb of software in memory substantially smaller and a non writable media. It has taken me by surprise.

I glad to see that you are moving to the point of changing caps. Hope it works for you. I havea feeling that there is another problem, due to the time it takes for afreeze to happen. I will be interested in the result.

[davmax]

Re: GA-8S655FX with very hot FET

Checking the Ubuntu web site the system requirements state a need for 4Gbytes of hard drive space. Clearly I do not understand how you are running Ubuntu.

[anonbeat]

Re: GA-8S655FX with very hot FET

Checking the Ubuntu web site the system requirements state a need for 4Gbytes of hard drive space. Clearly I do not understand how you are running Ubuntu.

You can install Ubuntu as a standalone operating system or run it from its Live CD. You can use it as a testing tool as it runs from CD and recognizes quite all hardware out there from CD. Also comes with memtest86 from the live cd.

I recomend it for testing hardware. Try it!

[PCBONEZ]

Re: GA-8S655FX with very hot FET

You only need hard drive if you intend to install it on the system.
That is optional.

[davmax]

Re: GA-8S655FX with very hot FET

Thanks guys. Very interesting.

[davmax]

Re: GA-8S655FX with very hot FET

Downloaded and ran Ubuntu from CD. First impression is not too good. The Memtest version is 1.7 , latest is 3.4. Hardware testing is too simple and basic, the video test did not work. Have seen much better. Suspect a lack of compatibility with the P45 chipset.

[anonbeat]

Re: GA-8S655FX with very hot FET

Just ordered the caps for my board. It will take about 10 days to arrive

It may have issues with too new hardware but for me it does what I need to. Dont forget its running in memory from a 700Mb CD only.

Greets