So, my guess is something is telling the busses to not send adequate power through the cable or pci card. Could a faulty motherboard component do that? Is there an equal component on the mobo, such as a Power Manager in a laptop computer?
It's extremely unlikely. The power connections on the PCI slots are all straight conduction connections to the power plane (layer) of the motherboard. The motherboard power plane connects to the appropriate pins on the power supply plug without intervening components. There's no way any component could be interfereing if it wanted to.
To summarize, if you take an ohmmeter and touch one end to the 5V pin(s) in any of the PCI slots and the other probe to any of the 5V pins on the power supply connector, you'll find that there is 0 resistance--or at least less than 1 ohm....
Similarly for probing between the power pins on all the PCI slots. That stuff is all connected by copper.
One little thing, what about the order of the cards? Does more power also go to the top two pci slots?
No. All the slots are on the same power bus as all the rest of the components, and there are no intervening components between them and the power supply connector on the motherboard.
I would say that the weak link is likely to be your card, but you said it worked properly on other machines.
It is possible that you either have a weak power supply (stock Umax supply is 250 watts, which is largish) or that there is a component on your motherboard causing a weak short which is draining some portion of the available power, or some other problem we have not thought of. For example, are you sure that the root problem is a lack of power to the peripheral?
One list member had a short between his 3V and 5V supplies in his DEC 21052 chip. Very odd, as the 21052 doesn't use the 3.3V supply, but there could be a route to it through the PCI bus clock signal trace.
A more likely source for shorts would be in the filter capacitors scattered across the board, but finding any such problem would be difficult.
Jeff Walther
-- SuperMacs is sponsored by <http://lowendmac.com/> and...
Small Dog Electronics http://www.smalldog.com | Refurbished Drives | Service & Replacement Parts [EMAIL PROTECTED] | & CDRWs on Sale! |
Support Low End Mac <http://lowendmac.com/lists/support.html>
SuperMacs list info: <http://lowendmac.com/supermacs/list.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/supermacs%40mail.maclaunch.com/>
---------------------------------------------------------------
The Think Different Store
http://www.ThinkDifferentStore.com ---------------------------------------------------------------
