Attila Kinali <[email protected]> writes: > I finally got around to measure the internal supply pins of my > net5501 to see what exactly is going on. What i see are very very > short (<1us) drops of the 12 down that are larger than 1V. I guess > the drops of the 3.3V and 5V supply that i see at the same time > come from the 12V drop. But with the measurement equipment i have > here and the lack of schmeatics, i cannot be sure. (it could be the > other way as well)
You could try putting a capacitor across the supply. 1us duration drops of more than 1V sound pretty suspicious though that something in the output filtering of your supply is messed up. It could also be that something is drawing outrageous currents at 3.3V which is stressing the regulator's current-handling ability and this is appearing upstream. But that seems less likely than a supply with something wrong (a bad output filtering cap, perhaps). > Hence i'd like to try another power supply but i don't have any > 12V with >3A here, only a 16V. Unfortunately, there is no specification > on what the net5501 can take as 12V suplly and whether these 12V > are connected to the harddisk or PCI connectors. (Someone else answered this already.) I have a hard time believing that a supply that will provide 12V 3A would have trouble. But I can believe that a particular supply labeled 12V 3A would not actually provide that reliably. > Hence i would like to ask the following questions: > * What is the exact specification of the 12 supply input? > * Where are those 12V connected to? > * Is there any stabilization or voltage limiter between the supply input > and the harddisk and/or PCI connector? I'm not soekris, obviously, but my limited understanding is the net5501 only uses 5V and lower, actually the disk connector is a notebook disk, which is at most a 5V device same with PCI There is a regulator (perhaps a 7805) that brings 12V down to 5V. One can jumper to not use the regulator, and then the input has to be exactly 5V. I am using a net5501 with the input connected to a bunch of 12V lead acid batteries (in parallel), more or less a 12Ah, 4 7Ah and 4 4Ah, all on float charge and thus ranging from high 11s to 14.5V, typically 13.4V or so. This has worked fine.
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