Can cpu or a8v mb fry if 4-pin 12-volt power not connected?

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captnorm

Recently bought Asus A8V deluxe, AMD 3500+ socket 939 cou, Corsair
ram... System won't POST, no video at all, no beeps on speaker.

Vendor thinks cpu or A8V or both got fried as I forgot to connect the
4-pin 12-volt power connector.

In re-reading the Asus manual, it says:
.... this motherboard requires that you connect the 4-pin to provide
sufficient power to the cpu.

.... otherwise the system doesn't boot up.

NOTHING about the consequences of not connecting it, like frying
anything, just that "otherwise the system doesn't boot up."

I've read the threads about bios version issues with this combination
& forwarded them to my vendor. I would just like to get a concensus if
anyone thinks I did NOT fry the cpu or MB, or if that is very possible
by providing no power to the cpu.

BTW, my email address has a 101 before the @, not 102

Norm Perron
 
captnorm said:
Recently bought Asus A8V deluxe, AMD 3500+ socket 939 cou, Corsair
ram... System won't POST, no video at all, no beeps on speaker.

Vendor thinks cpu or A8V or both got fried as I forgot to connect the
4-pin 12-volt power connector.

In re-reading the Asus manual, it says:
... this motherboard requires that you connect the 4-pin to provide
sufficient power to the cpu.

... otherwise the system doesn't boot up.

NOTHING about the consequences of not connecting it, like frying
anything, just that "otherwise the system doesn't boot up."

I've read the threads about bios version issues with this combination
& forwarded them to my vendor. I would just like to get a concensus if
anyone thinks I did NOT fry the cpu or MB, or if that is very possible
by providing no power to the cpu.

BTW, my email address has a 101 before the @, not 102

Norm Perron
Click to expand...

I can't say for certain that it's impossible, without a detailed circuit
schematic of the board, but I think it's very unlikely that not
connecting the ATX12V connector would damage the board. It likely just
won't boot.
 
Try clearing the bios with the jumper and make sure the power cord to the
computer is unplugged when you do it.
 
Is your 3500+ one of the new 90 nm "Winchester" chips? The A8V will not
post with these unless you update the bios. The older bios only understands
the original 130 nm CPU. There is a lot of info on this problem out there.
Use Google.
 
I have no idea! It's a retail box, says 3500+, 939 socket, AMD Athlon
64 Processor with HyperTransport Tech. In small print says 640KB
cache, operates at 2200MHZ. Been thru all documentation, no mention of
Winchester, 90 or 130 nm. I even searched their knowledge base, they
don't have any info on any of these 3 searches.

I wrote down all info stamped on the actual cpu. Best part # is
ADA3500 DEP4AW, if that helps determine. Found:
ADA=AMD Athlon,
3500
D=939 pin
E=1.50 volt
P=70 degrees cent
4=512KB cache
AW=rev CG

Norm
 
General information

a.. Manufacturer: AMD
a.. Manufacturer Part number: ADA3500DEP4AW
a.. Product Line: Athlon
a.. Product name: Athlon 64 processor 3500+
a.. Manufacturer website address: www.AMD.com
a.. Package quantity: 1 OEM
a.. Package detail: 1 x processor
Technical information

a.. Clock speed: 2.2GHZ
a.. cache memory Details: 64KB L1 data CACHE512KB L264KB L1 instruction
cache
a.. cache memory: 512KB L2128KB L1
a.. Form factor: 939-pin O PGA socket 939
a.. Architecture: 64-Bit
a.. Process technology: 0.13 M
a.. Multimedia extensions: Mmxstreaming SIMD extention (sse)3DNOW!streaming
SIMD extention 2 (sse-2)
a.. Featured technologies: Hyper-Transport technology
Compatibility

a.. Platforms: PC
a.. products: Abit AV8 via K8T800 proecs KV2 via K8T800 progigabyte
GA-K8VNXP939 via K8T800 promsi 7025 nvidia NFORCE3 ultraasus A8V via K8T800
progigabyte GA-K8NSNXP939 nvidia NFORCE3 ultramsi 6702E via K8T800 Pro
Power description

a.. Input Voltage: 1.5V DC core
 
Robert Hancock said:
I can't say for certain that it's impossible, without a detailed circuit
schematic of the board, but I think it's very unlikely that not
connecting the ATX12V connector would damage the board. It likely just
won't boot.
Click to expand...

The power sequencing requirement is section 7.8.3 "Power Supply
Relationships" on page 76:

http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31411.pdf

All that this info adds to the puzzle, is that it is possible.
(VDDA and VDD come from a +12V powered circuit. The kicker is,
where does VLDT come from, as VLDT should not be allowed to
rise, if VDDA/VDD are not running yet.)

But I would think unlikely, as there _should_ be provision in the
circuit to meet the requirements under normal circuit operation.
When a circuit has a sequence requirement, there should be stuff
in place to meet it, such as diodes or MOSFET switches. In my
experience with circuit design, there are extensive discussions
during the design phase, about exactly which of these requirements
really need to be met, as cutting costs and meeting sequence
requirements are competing objectives. In some cases, it takes
3 months to get answers from the factory, on whether all these
requirements are necessary or not. In extreme cases, the circuit
schematic may be reviewed by the chip manufacturer, for
correctness.

I suppose Asus could think along the lines "well, only the
processor will get burned if we do this", but imagine how much
future support Asus would get from AMD, if Asus causes a few
million Athlon64s to get replaced under warranty. And if the
user community became aware of it, it could have quite an
impact on future business. There is no upside to cheating on
the circuit requirements, which are clearly stated in the
datasheet.

HTH,
Paul
 
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