Precision 690 FlexBay USB header pinout

Keywords: PWS690 FlexBay Flex Bay USB header pinout pin out internal connector motherboard mobo system board

I purchased a Precision Workstation 690 six months ago, admittedly late in the game for the 690. I had a 3-1/2" combo floppy drive card reader which uses an internal USB connector for the card reader functions. To connect to the Dell FlexBay header, I did some research on previous endeavors by others. Some were working on the same problem but on a Precision 390 or another model. Using their work, I successfully located enough info to determine the pinout and was able to get the card reader working. This is a posting for the record, to allow others to use this information.

The FlexBay header connector (number 19) on the system board is shown in the Precision 690 User's Guide under "About Your Computer":

<ADMIN NOTE: Broken link has been removed from this post by Dell>

This diagram is oriented as if you had the 690 on its side with the cover off, with the back facing us.  Actually, the FlexBay header is thus at the "top" of the system board close to the four SAS/SATA drive bays.  I will disregard the diagram and use the term "up" to describe the top of the 690 case, with ther computer on its feet.  In this position, the header is toward the top of the system board and the keyway or key for the 10-pin connector is also up (toward the four drive bays).

I have seen some discussion that the pin spacing on the connector is non-standard.  I cannot agree.  I found the spacing to be the same as any internal USB plug and header.  To find what the standard pin numbering might be, I located this diagram:

http://hardforum.com/showthread.php?t=1392911

If you look at the USB2 layout, you’ll see that the Precision 690 FlexBay header appears to be the same except that all the pins 3,5,7 and 9 are missing.  We only need to use 2,4,6 and 8 for a standard internal USB connector from a front-panel card drive.  I know this because I took a voltmeter and checked the pins while the 690 was running. I read 5 volts on Pin1 and Pin2 and found that I could get a ground on Pin8.  Pins 4 and 6 had less that 5 volts, so I decided to try hooking up the card reader USB connector to 2,4,6 and 8 with +5 volt connector to Pin2 and ground to Pin8.  This turned out to be the standard pin arrangement for my card reader using the 4-pin connector that came with the card reader.  But others might wish to use a 10-pin connector with key, to get a perfect match to the system board header.

I realized it was possible to find a perfect 10-pin connector with key, if I wanted to do a little work.  I found two good ones at a local computer “parts yard” that had bins of used computer parts and cables.  One part was a back-panel slot filler with two connectors:  a 25-pin serial connector and a 9-pin serial connector.  The 25-pin serial connector was wired with a flat ribbon cable with an IDC 10-pin plug on the other end.  It looked like the connector on the following page, below the words “All pins joined Intel style connector”:

http://www.directron.com/installusb.html

The other plug was even a better candidate. It was a plug with key which originally went to two USB ports on a back-panel slot filler.  If I wanted to, I could easily have pulled out all the pins (gently!) and taken the correct pins from the 4-pin card reader connector to put in their places, in positions 2,4,6 and 8.

http://1.bp.blogspot.com/_tywx91-IYbc/SfG4RKjhTgI/AAAAAAAAAOU/sqcNYDPtB3Q/s1600-h/usb2.0.jpg

In short, you can use the 4-pin connector to plug directly into the Precision 690 FlexBay header, as long as you ensure you have the pins in the correct position.