To Open The Sky
The Front Pages of Christopher P. Winter
Adding a Second CPU to the HP Kayak
Finding the Proper Voltage Regulator Module
In the various dual-processor Kayak models, each processor installed requires its own, separate voltage regulator module or VRM. The same is true of other computer models that use HP's Slot 1 or Slot 2 processor modules. The type of VRM you need depends on what processors you use. The table below contains all the information I've been able to find (as of January 2008) on the specifications of HP VRMs and which processors they match. The information is incomplete because HP no longer supports most of these modules.
Fortunately, once you identify the type of module you need, you'll almost certainly be able to find it. Obsolete HP parts of all kinds are available from a host of distributors. In most cases, VRMs for Kayaks and computers of similar vintage are quite reasonably priced. If you can't find the specific module you need, or want a lower price, give eBay a try.
If you're in search of more information, your first stop should be HP Partsurfer. Searching on the part number should get you the basic specs and a list of computers that use that module. HP's discussion forums can also be useful, although the information about Kayaks will be dated and takes some persistence to uncover.
1 Hewlett-Packard generally assigns its part numbers in sequence. It's unclear why a module with a higher part number (hence more recent) was replaced by an older one. More important, I haven't found the reason for the change. I have been able to determine that both types have the same ratings for input voltage, output voltage, and current. My best guess is that it has to do with the range of control voltages. This matters because 0950-2837 is rare, while 0950-3310 is fairly plentiful on the surplus market.
2 I have no idea why these different VRMs carry the same manufacturer part number. I've seen it on several sites. If I had to bet, I'd bet the manufacturer's number goes with 0950-2848.