ASCIi Group
Review of Post-Probe
by Bill Funk
The Post-Probe is a card that plugs into a PC's PCI or ISA slot, designed to offer the user a way to diagnose the PC's POST; POST is an acronym for Power On Self Test. The POST will check a PC's hardware before starting the Operating System (OS); often, the POST will catch problems that will keep the system from operating at all. When the POST completes each step in the test, it generates a code; the POST PROE will read those cards, and help to determine which test failed during the POST. This code is displayed on a 2-digit display on the card.
If your PC won't boot, it's often a hard task to find exactly what the problem is. There are a host of things that can cause a problem, and some won't even show up.
Above, you see the Post-Probe card. You can see that the card has connectors for both PCI slots (on the bottom) and ISA slots (on the right side), so it can be used to check systems with either type of slot. There is an adapter available for systems with MCA slots. Along the top edge, there are a series of LEDs; the first five will indicate whether or not the power supply is putting out the right voltages. The next series of LEDs will indicate such things as the CLK signal, transmit/receive states, etc. A 2-digit display is near the upper right corner, below the DIP switch. This is where the POST codes are displayed (there is another such display o the back side of the card to assist in reading the codes if you can't see the front side). Below the LEDs there is a row of test points for accurately measuring the voltages put out by the power supply. There are also two stepping switches that allow you to step through the POST one test at a time.
Above is the manual that comes with Post-Probe. This is a 190 page book, and it goes into some detail about what the card will do. Included are the instructions for installing and reading the card's output, of course. But the best part is a fairly complete listing of the POST codes of most of the BIOS chips/versions that you will come across. This is necessary for understanding the codes displayed by the card. Some of the code descriptions are a little arcane, and require more study (this is more a function of the descriptions put out by the BIOS makers than a problem with Micro2000), but those who are more familiar with the workings of computer systems will have only a little trouble figuring the descriptions out.
As an example of this, one of the slots in my desktop system showed two errors; the OSC LED stayed on solid when it should have blinked, and the displayed showed a code that was described as "If An EISA NVM". Rather cryptic. NVM stands for Non Volatile Memory, and the solidly lit LED means that the OSC (oscillator) signal wasn't getting to the card. Since the system continued the POST, and loaded Windows OK, and the other slots didn't show any problems, I came to the conclusion that there is a problem with the printed circuit traces for that slot. Since I only have 2 cards in my system, I just don't use that slot. I did have my sound card in this slot, and the sound from some sources was scratchy; moving the card to another slot solved that problem.
The manual also contains a listing of the "Beep Codes" for most of the BIOS types you will find. Also, the IBM error codes are shown.
Post-Probe is not a magic card that will automatically diagnose a dead computer. Instead, it's a tool that will aid the user to figure out the problem, and help suggest a cure. Many of the POST problems can only be solved by replacing the motherboard or CPU. Others can be solved by replacing RAM modules. The Post-Probe will help you determine which solution will be the right cure.
The Post-Probe has a 1-year limited warranty, and is a product of Micro 2000. Check their web site for more information.
The Post-Probe card can be found on the Internet for about $425 to $500.
The Microscope diagnostics (see review in August CLIPBOARD) and the POSTPROBE card can be bought as a Universal Diagnostic Toolkit, and costs about $900. Prices are approximate; Micro 2000's website doesn't offer their products directly.
Because of the cost, this is not an impulse buy, and it's hard to find locally at a retail outlet. For the technician, or dedicated hobbyist, the Post-Probe offers what I think is a very good tool for diagnosing POST problems which would otherwise be very difficult to find.