Chuck322
2 Bronze

Strange USB PCIe card BIOS issue - only on 1 of 2 identical Optiplex 760 MTs

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About a month ago I bought 2 Dell Optiplex 760 MTs. Both systems are exactly the same in every way and work very well.  Both have the latest A16 BIOS and all the latest drivers from Dell installed.

Last week, I bought a Dodocool 2-port USB 3.0 PCIe expansion card and it works on both Optiplex 760 PCs when placed in either the PCIe x1 or x16 slots.  HOWEVER...

On only one of the systems, it's a hit or miss as to whether the BIOS detects the card from a cold start up (the BIOS detects all the PCIe slots, just sometimes not this particular card - it will just show "empty", when it should say "USB").

As a result, if the BIOS doesn't detect the card, then it's not available in Windows when Windows loads in. Therefore, when I start the PC, I always have to enter the BIOS to see if the card is detected before windows boots.

If BIOS shows the card I just exit the BIOS and let the PC boot into Windows and all is fine.

But if the BIOS doesn't detect the card, I have to exit the BIOS, push the power button on the tower to shut the system off, then power on again and re-enter the BIOS and find that the card is recognized (sometimes might take 2 or 3 tries but many times only one try is sufficient).

It never happens if I simply do a restart from the OS. On a restart, the BIOS always remembers/sees/detects the card. It only happens if I do a shutdown and have to power-up the system using the power button on the tower.

This problem happens only with this one system and only with this particular PCIe card and not any other PCIe cards and it doesn't matter if it is installed in the PCIe x1 or PCIe x16 slot - the problem is the same. No problems on either PCIe slot with any other PCIe cards.

I have tried many many times to replicate this problem on the other identical PC but I cannot replicate it.  The BIOS on the "good" PC detects this PCI card every single time.

At first I thought it was a defective mobo or defective PCIe x1 slot but when I saw that it also happens on the PCIe x16 slot and other PCIe cards I've tried get detected by the BIOS with no problems, I don't think I can conclude it is a bad mobo or slot(s).

I also don't see how it is a defective PCIe card since it works flawlessly on one system. In fact, it works on both systems, just that in one the BIOS might not detect it on just one of the PCs.

I'm hoping someone here can shed some light on this. 

Here is a list of everything I have tried...

  • Flashed the BIOS 3 times now (A16 BIOS).

  • Bade sure the card was seated properly every time.
  • Tested voltages both PSUs under load. Both systems' voltages tested out fine.

  • Ran the command "bcdedit /set CONFIGACCESSPOLICY DISALLOWMMCONFIG" in Safe Mode with command prompt. I did this because I read an old thread from another forum for a similar problem and this fixed that person's problem. But it did not fix my problem. Admitedly I am not quite sure what this command really is. 🙂

  • Reset the CMOS with the jumper and removed battery for several minutes.

  • Replaced CMOS battery with fresh one, even though the old one tested at 3.1v.  New battery tests out at 3.2v.

  • Used the RAM from the "good" PC on the "bad" PC.  No change to situation

  • Reinstalled (several times) the latest Renesas 201-202 USB driver for this card v3.0.23.0.

Both systems specs:

  • Dell Optiplex 760 MT
  • Nanya 6GB DDR2 PC2-6400 (800MHz) RAM
  • Intel Core 2 Duo 3.0GHz E8400 CPU
  • Dell Inc. 0M858N mobo
  • Dell BIOS vA16
  • Windows 7 Pro 64-bit SP1 (using on-board graphics for both)

I appreciate any help on this matter.  It's driving me nuts! lol

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Chuck322
2 Bronze

RE: Strange USB PCIe card BIOS issue - only on 1 of 2 identical Optiplex 760 MTs

Jump to solution

The problem is solved!

I was wrong to just test the output voltages on each PSU and not switch them out. The problem is in fact the PSU.

This morning I decided to take a look at the spec sticker on each PSU and, lo and behold, they are not identical. They look identical but each has a different part #.

- The part # on the problem PC's PSU is P192M, model # L305P-03.
- The part # on the "good" PC's PSU is 0MK9GY. model # H305P-02.

All the specs on the stickers are identical expect for the input specs.

- On the problem PC (PSU P192M), the input says 100-240V~/5.6A (50-60Hz) (which is the same as many of the "Bronze" aftermarket PSUs I have been looking at recently online)
- On the "good" PC (PSU 0MK9GY), the input says 100-240V~/4.7A (47-63Hz).

I'm not sure if these specs are what make the difference, I'm just pointing out the differences in the specs on the stickers. If very well could be that the input specs mean nothing and that the P192M is starting to fail, but I have had no other problem than the intermittent detection of this USB card using the P192M PSU. The PC with the P192M part # was manufactured about 8 months before the PSU with the 0MK9GY part #, so it could be that Dell replaced it due to this defect I am seeing.

So now, the P192M PSU is in the other PC (the "good" one) and now that PC is suffering the same problem - intermittent detection of this one PCIe card in either PCIe x1 or x16 slots.

And now, the problem PSU has the 0MK9GY PSU in it and it is no longer the "problem" PC, it is now the "good' PC. Detection of the PCIe card in either x1 or x16 slot is always detected...ALWAYS!

So the formerly "good" PC is now the problem PC and the former problem PC is now the "good" PC, all because of switching the PSUs!

  Just goes to show you that testing output voltages, even under load, is not a 100% indicator of a faulty or "problem" PSU!

1 Reply
Highlighted
Chuck322
2 Bronze

RE: Strange USB PCIe card BIOS issue - only on 1 of 2 identical Optiplex 760 MTs

Jump to solution

The problem is solved!

I was wrong to just test the output voltages on each PSU and not switch them out. The problem is in fact the PSU.

This morning I decided to take a look at the spec sticker on each PSU and, lo and behold, they are not identical. They look identical but each has a different part #.

- The part # on the problem PC's PSU is P192M, model # L305P-03.
- The part # on the "good" PC's PSU is 0MK9GY. model # H305P-02.

All the specs on the stickers are identical expect for the input specs.

- On the problem PC (PSU P192M), the input says 100-240V~/5.6A (50-60Hz) (which is the same as many of the "Bronze" aftermarket PSUs I have been looking at recently online)
- On the "good" PC (PSU 0MK9GY), the input says 100-240V~/4.7A (47-63Hz).

I'm not sure if these specs are what make the difference, I'm just pointing out the differences in the specs on the stickers. If very well could be that the input specs mean nothing and that the P192M is starting to fail, but I have had no other problem than the intermittent detection of this USB card using the P192M PSU. The PC with the P192M part # was manufactured about 8 months before the PSU with the 0MK9GY part #, so it could be that Dell replaced it due to this defect I am seeing.

So now, the P192M PSU is in the other PC (the "good" one) and now that PC is suffering the same problem - intermittent detection of this one PCIe card in either PCIe x1 or x16 slots.

And now, the problem PSU has the 0MK9GY PSU in it and it is no longer the "problem" PC, it is now the "good' PC. Detection of the PCIe card in either x1 or x16 slot is always detected...ALWAYS!

So the formerly "good" PC is now the problem PC and the former problem PC is now the "good" PC, all because of switching the PSUs!

  Just goes to show you that testing output voltages, even under load, is not a 100% indicator of a faulty or "problem" PSU!