Asrock 775V88+ Mobo

[lagacy]

Re: Asrock 775V88+ Mobo

I have not got round to testing the SOT-23 SMT devices.
There are a number of these on this system board.
I will do so now as well as replacing the TL431 discrete regulator.
The TL431 is present on the Asrock 77588+ mobo near the s/bridge.

Are you referring to the transistor as failed on an Asrock 77588+ mobo,
or are you referring to another Asrock system board?

Thanks for the tip.

Sorry. I don't remember the model No because I dit that last year.

[JEWilson]

Re: Asrock 775V88+ Mobo

I have not got round to testing the SOT-23 SMT devices.
There are a number of these on this system board.
I will do so now as well as replacing the TL431 discrete regulator.
The TL431 is present on the Asrock 77588+ mobo near the s/bridge.

Are you referring to the transistor as failed on an Asrock 77588+ mobo,
or are you referring to another Asrock system board?

Thanks for the tip.

[lagacy]

Re: Asrock 775V88+ Mobo

Coud you try to locate a SMD transistor positioned nearby the power-on/reset pins. I used to detect a broken B pole. I replace it with a NPN 600ma general purpose transistor and it is fixed. Another Asrock 845 got the same symtom but this one has a defective TL431 located near the south bridge.
A "special" characteristic of Asrock mobo is that it does not work with "aging" IDE cable while other mobos were not affected.
Hope that would help

[JEWilson]

Re: Asrock 775V88+ Mobo

Y - I thought that may be an issue

I have replaced the RTC xtal.
I also pulled the VRM caps to test these out of cct. as well
as being able to test the MOSFETs.
These are all good.

Further, I tested the temps on both the s and n/bridges
These both raise about 8 deg C after more than several
minutes after power on. This might confirm these are both ok.

The problem you indicate whilst being plausible presents me
with a problem. If I have a bad BIOS image whether via using
the Willem (or not), as I cannot get the system to boot,
the only way to address this would be to get a copy of
a known good BIOS for this system mobo in a plcc package.

Hmm.... where could I get this?

Thx

[gonzo0815]

Re: Asrock 775V88+ Mobo

Regarding your flash problem with the willem, AFAIk asrock does use some flash protection bits. The only program to handle those is the Asrock flash proggy.
i am not sure, if your particular board is protected this way too.

[JEWilson]

Re: Asrock 775V88+ Mobo

I've got back to testing this mobo.

First, I replaced the OST RLPs with Panasonic FM and FJs.
Several of the OST reported higher than spec. ESR when
pulled from the mobo (out of cct.).

Next, I require some clarification on a clock issue.

I tested the 32.768kHz xtal on this board with the freq.
test range on my mmeter. This item appears bad as
it does not appear to be within spec.
Conclusion - replace the xtal (part has been ordered).

Q - would this impact on the BIOS failing to be read?
I understand the VIA VT8237R s/bridge uses this for
the RTC. If the clock source is in error, would this
account for the symptom?

I use a PCI POST Diag Card and this reports all voltages
appear ok as well as the ISA OSC frame being present
as well as the clk LED being lit. By clk, this must obviously refer
to the PCI clk (33 MHz).
If this is correct, as the clock synth generates the
CPU, AGP and PCI clks - it may be these are ok.
The synth chip has, as is common, a 14.318MHz xtal source.

As the POST/Diag card reports a CPU reset but that
is as far as the boot process gets, it is unclear
if the LPC interface to the BIOS has a strobe.
I can't immediately determine if the RTC source is
symptomatic of the boot issue.
Perhaps a number of the members can refresh my memory
here.

Unfortunately, my mmeter only has a range up to 200kHz
Hence, I cannot be sure about this.

The only xtal is the 25MHz LAN PHY xtal.
Again, I cannot test this with my mmeter

As an aside, can someone recommend a standard mmeter
with a freq. measure up to 20MHz and above?

[JEWilson]

Re: Asrock 775V88+ Mobo

Yep - correct
It is only warm to touch - it does not get extremely hot,
neither does the southbridge.

I have a couple of mobos for repair, which, at boot, gets the
southbridge very hot - too hot to touch and I cool them
with freezer spray. Clearly there is a short on these boards
as PS-ON is not set and the PSU stays off.
You can of course force the PSU on which is how I identified
the southbridge matter with those mobos.

I suspect there is a short or shorts, possible to the regulation of these
devices but that's another story and I never let those get to
a thermal runaway condition - promptly sever power to the boards.

Thanks

[zandrax]

Re: Asrock 775V88+ Mobo

Via northbridges aren't hot: the heatsink may be warm and it's normal, but being so hot you can't touch it isn't normal. Let's hope it isn't a shorted chip.
Keep us updated.

Zandrax

[JEWilson]

Re: Asrock 775V88+ Mobo

Well...

I flashed the original BIOS (v1.3) as came with the mobo
with the correct uCode patch but the mobo is still no go.
The mobo certainly appears to have all the voltages
stable and does a CPU reset but does not get to the stage
where it will load the BIOS.

My port 80 POST card reports this to be so.

I did have a problem with my willem programmer writing
the updated BIOS to the plcc device. This is odd.
It did work after I retried the flash.

I have done as above basic testing of cap ESR and test
for o/c and s/c on the ATX power connectors. These
are all ok.

Now, as a result, I'm beginning to suspect the BIOS device.
The heatsinked northbridge get slightly hot.
I believe that is ok, but....

I will need to get meter readings of all of the relevant parts
of the mobo. This will be;
VRM for the CPU - I/P and O/P sides
DC-DC block for memory.
Supply voltages to the BIOS IC etc.

Thanks

[zandrax]

Re: Asrock 775V88+ Mobo

Strange: the flasher should copy almost everything, uCode updates included, except the boot block.
Try using Uniflash: maybe it works on your board.

Zandrax

[JEWilson]

Re: Asrock 775V88+ Mobo

I may have resolved this issue.
Will report back once established fix has worked.

First, the bios image (v1.3) as came with the board had
a number of uCode patches. One of these i.e.
CPUID 0F43h, Revision 0x04 11/01/2004 does not appear to exist.
In fact, the correct patch should be;
CPUID 0F43h, Revision 0x05 21/04/2005

This is why (I believe) the PIV 650 Prescott was not working.
No uCode existed to support the CPU.
The system would always reset and do nothing.

Of course, Asrock supplied later BIOSes with a number of
uCode patches but they insist these are to be applied with the
supplied flash utils.

Now, I did try flashing with later BIOSes but of course was not
aware of the uCode issue with the v1.3 BIOS and using a
Willem, only flashed the image not the supplied uCode patches.

I have used MMTool 3.19 for Windows to patch the correct uCode for the v1.3 BIOS
and removed the incorrect entry.
This has been applied ok but remains to be tested with a CPU
and memory.

MMTool 3.19 for Windows reported prior to patch update;
CPUID 0F43h, Revision 0x04 11/01/2004 - incorrect
CPUID 0F33h, Revision 0x0b 05/12/2004 - correct
CPUID 0F34h, Revision 0x13 30/07/2004 - correct
CPUID 0F41h, Revision 0x09 02/08/2004 - correct

AMIBCP v3.13 for Windows reported;
CPUID 0F43h, Revision 0x04 11/01/2004 - incorrect
CPUID 0F33h, Revision 0x0b 05/12/2004 - correct
The last two as with MMTool were not reported

Also v3.13 for Windows reported as;
ID String 1 - 62-130-0000010-00101111-042505-VIA

But this does not make sense. I know of no manufacturer
as above.

Any insight from forum members?

[starfury1]

Re: Asrock 775V88+ Mobo

well no idea on that MB as to a likely cause.

I guess computers now are the same as old, basic function wise

Id check the VRM if you haven't already
voltage rails and osc (clock)

If there are those tiny xtals used on the MB I have known them to fail
but on MB's, how often... no idea
(or even if they still use them, maybe its contained in a clock generating chip)

I'd give the MB a good visual too with a loupe or good mag glass, looking for possible dry joints.

there are from memory small fuses that may be used on MB's so maybe one of them has popped

maybe its just at the "write it off" stage considering the time you may have to spent on it.

As I've said before grab some chip numbers and see if you can get a PDF this may help in trouble shooting.

BGA solder joints have been known to fail so maybe apply a bit of pressure here and there to see if it is a bad joint.

unfortunately not an answer for you , just some things to try or look at.

Cheers and good luck

[JEWilson]

Re: Asrock 775V88+ Mobo

I constructed an audio lead with a speaker to attach to this mobo.

I get no beep codes at all.

The system simply sits and does nothing after a CPU reset,
similarly so when a reset from the front panel is processed.

FWIW - the CPU and n/bridge HSFs are becoming marginally
less cold than at power on as best as I can tell from simply
touching these.

I am going to try a different bios chip (if I can find one).
Perhaps the BIOS IC in situ is not working albeit I have
successfully erased and programmed this device before.

Any other suggestions?

[JEWilson]

Re: Asrock 775V88+ Mobo

CPU is known good

Difficult to tell if the CPU is getting warm with the Intel s775 HSF in the way.

I don't have a thermacouple to test CPU temp for sure.

The POST card does report a CPU reset as part of the boot process.
After that, POST read out sits at 00 00

As the mobo does have a 4 pin header for a speaker/buzzer - I think,
next, I will mount a speaker/buzzer to determine if I am getting a
beep code alarm for RAM or the like. If I can determine this to be the
case, then as the RAM is good, it may be a problem with the DC-DC
block for RAM - this might be bad caps and/or regulator related.

Q - During boot, after the CPU reset, the CPU should read address
FFFF:0000 and execute the assembler jump to read and uncompress
the BIOS image and load it into RAM. Of course, it RAM cannot be
read, would this indicate the failure to load BIOS

Any help - appreciated

[Harvey]

Re: Asrock 775V88+ Mobo

Is the CPU getting warm?

[JEWilson]

Re: Asrock 775V88+ Mobo

Finally got round to some further testing with this;

As you suggested, I followed the instructions to reset the BIOS.
Result - still no POST.

Next, I reseated the BIOS IC (it is socketed) as, strange as it seems,
I have had problems with this before.

I have tried two different PSUs - these were;
Q-Tec 550W Dual Gold Fan (premium recapped) and FSP (Fortron/Source) FSP350-60MD 350W
I have tried two different types of RAM - these were;
Elixir PC3200 512MB DIMM in single channel and Corsair XMS PC3200 512MB in single and dual channel (have 2 of)
I have tried two different graphics adapters - these were
XperVision GeForce FX5700 LE AGP 8x 256MB and Jace Tech J2225 (a GeForce FX5200) AGP 8x 128MB

The problem persists - any further suggestions?

[gonzo0815]

Re: Asrock 775V88+ Mobo

Try a CMOS clear first, by removing battery, any power plugs and shorting CMOS clear Jumper.

I have had some Asrock boards which needed this procedure to successfully boot.

[JEWilson]

Rec's this in unknown condition.
Physical inspection finds underside has a few scratches - cannot find any
traces s/c.

Tried power up with a post card and AGP graphics adapter installed
with suitable RAM. Result - NO POST.

Everything appears ok voltage wise but it cannot load the BIOS.
When mobo switched on, all voltage readings on the POST Card
appear ok and the system will do a CPU reset.

I checked the BIOS and find the correct version with my programmer.

So... turning, to look at the caps on the mobo

This board has;
4 of 16.0V 1200 uF NCC KZE - published ESR is 0.022, readings 0.03-0.04Z
6 of 6.3V 3300 uF NCC KZG - published ESR is 0.012, readings 0.04-0.06Z
22 of 6.3V 1000 uF OST RLP - published ESR is 0.078, readings 0.08-0.12Z
4 of 16.0V 100 uF Teapo SS - published ESR is dunno

I cannot find the ESR for the Teapo SS but did find readings with my ESR
meter varied from 0.22, 0.41, 0.59 and 0.56. Are these normal?

I don't think the KZE and KZG are problems - what do you think?