Poweredge 1500SC won't boot with second CPU installed [EVEN WITH SECONDARY VRM]

Question

Hi,

I posted this message a few weeks ago:

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I have a Dell PE1500SC which currently has 1xPIII 1133Mhz 512/133 processor installed (Part Number SL5PU). I have bought a second identical processor to upgrade the server. The server is currently running Windows 2000 Server.

I have changed the driver in Device Manager to ACPI Multiprocessor PC (instead of Uniprocessor) as per the instructions on the DELL FAQ's.

When I install the second processor however, the server tries to boot-up, and the power kicks in for about 3 seconds before shutting off. It almost seems as if the PSU can't cope with two processors at once.

I've tried switching the CPU's around, and they both work fine on their own in the CPU 1 Slot, the problem only occurs when they are both installed together.
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I got a reply at some point stating that the server needed the VRM to be installed which I have now purchased and done, but still get a problem.

With the secondary VRM and the 2 Processors installed, the same error occurs as above (Server starts, PSU Fan's kick in, regulate themselves to normal speed, and stop after a few seconds), and without the secondary VRM installed, but with 2 processors, the power starts and stays on with the PSU fan turning at a greater RPM than normal, but nothing happens, Bios doesn't kick in.

Does anyone have any idea why this could be??

Source4 · Answer

I have the same problem. VRM, matching CPU, cooling hardware, 1500sc power supply that shuts down before the BIOS even posts. I've downloaded and scoured all manuals and material that I could find available from Dell's website. I've called Dell tech support and found no joy after 90 minutes on the phone. I believe I have the proper VRM. Dell #7G041 OEM #24P6893. I've have used the secondary CPU (1.4Ghz in my case) as the primary to make sure it wasn't the fluke of a bad CPU.   I think the issue is defiantly one of power. I did see a blurb in the service manual that said in adding the second CPU and VRM to remove the mainboard VRM. I have redundant power supplies, so there is VRM mounted on the power distribution board. Yes I tried removing it with only the secondary CPU VRM with no luck. The secondary CPU VRM has a 5V - 12V selector on it (default 5V) and I tried it 12V. What's left? There is either a something else with the power and regulation system configured for one CPU that has to be changed or both you and I got burned on bad VRMs.   I'd love to know the solution.

undrop79 · Answer

Well, I'm still in the same position, I've tried calling Dell for advice, they've told me that they can only give me support if I buy the CPU kit from dell, which I've also tried, but they can't get hold of a compatible one anymore.

My last resort has been to buy 2 identical TUALATIN 1.4 GHZ INTEL III 1400 GHZ 512KB/1.45V on Ebay which should be arriving shortly for me to test (please don't tell me these CPU's aren't compatible with my system).

Anyway, if you get any luck or ideas, please let me know.

Source4 · Answer

Yes they are compatible. Intel white papers state that these CPU's of similar type with matching clock rates, regardless of stepping (version), should run as parallel processors, although I made sure the stepping of my CPU's matched (leave nothing to chance). I am sure this will not solve your problem as I am running these exact same processors, or processor since I can only get one to run at a time.   As for support, I believe they owe us at least the information to run dual CPU's, not trouble-shoot. I know it's a fine line but if the service manual is available to us, the correct information or complete information should be ours. Especially with systems this old and their difficulty in maintaining stock for such systems. I'm going to try Dell parts this time to see if I can learn something.   In the past ten years I have dealt with many dual and quad processor upgrades for small business I have worked for. It shouldn't be this hard. Should It?

undrop79 · Answer

Shouldn't be. I've not been doing this for as long as you have, but I have upgraded a single processor server to a multi-processor setup on a couple of occasions, and this is the first issue I've ever had.

I've gone down a number of avenues to try and come-up with a solution, so if you find anything please let me know.

Thanks

kanri · Answer

Hey guys,

I know that this post is really old, but I am experiencing the same problem and was wondering if either of you ever came across a solution. The System is a PowerEdge sc1500 that will not boot. BIOS will not even kick in. I replaced the motherboard already. I also replaced the Voltage Regulator Module on the Power Distribution Board. I have dual power supples, and they are both fine. The only other thing that I know to do is to replace the Power Distribution Board itself. If that doesn't work, then I don't know what to do. Any comments?

Thanks

wls-canada · Answer

This won't help you other than reassure you you're not losing your mind... I have two PE 1500SCs. The motherboard VRM with second CPU works in one of the units and not the other. I tried swapping the power distribution board, the cables, the power supplies themselves... no go. It seems tied to the motherboard itself (and they have the same A06 bios flashed). There seems to be no logical explanation... with one it boots up fine, with the other, the heavy fan and no-bios boot.

I have a third 1500SC that I just recently acquired from e-Bay; I will try on that unit as well and post results.

dherbots · Answer

I had the same problem with a different DELL server. Maybe the solution I found can help... you never know.

I have two old PE2650 servers for testing, they are identical twins but each with one processor.
If you join both processors and VRM's into one box, the servers starts and after a few seconds kills the power.

All parts were identical beside the VRM hardware release.

The solution in my case was to buy two identical VRM modules. Nothing else worked.

Not sure this helps.
D

PowerEdge Hardware General

Poweredge 1500SC won't boot with second CPU installed [EVEN WITH SECONDARY VRM]

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