[OT] Power and NIC questions

From: Neil Cherry <ncherry_at_home.net>
Date: Sun Aug 13 13:38:14 2000

Richard Erlacher wrote:
> I'll certainly second the statement about the Tantalum cap's. I once had a
> fire in my AMPRO system because of a shorted Tantalum, and, having seen the
> smoke emanating from the rear of the PSU (I hd used a PC-style case)
> immediately assumed the fault was in the often considered flaky power supply
> (this was in the mid-80's).
> In the process of prying the grommet with all the various power leads out of
> the supply case, I stuck a 1/2"-wide screwdriver I was using as a prybar,
> about 1" into my hand. (think about where you can stick a screwdriver 1"
> into your hand and not go out the other side ... ) Half a day and over $1k
> in medical expenses later, I looked at the Little Board and saw the burned
> spot where the cap had been. If Only I'd looked before I lept . . . <sigh>

Ouch, that's all I have to say about that ....
> About a year ago I once again was powering up an old Ampro Little Board,
> and, sure enough! ... the -12 was pulled down by a shorted tantalum bead.
> Apparently they do not age well.
> BTW, AUI uses -12 and +12 from the supply on most cards that support it.
> The coax gets an isolated negative voltage generated locally on the NIC,
> generally with a little switcher module. These are handy to hang onto when
> you're faced with a broken NIC. They generally make a nice -9-volt source
> for boxes that have no other negative supply, and that's satisfactory for
> RS-232.

Ah. the cap can still be a problem (many tant's on the MB). Well I'll see
what's going on a little later as I'll check the ub to see if it can see
a MAC address. This will fill me in on further details of the problem.

Linux Home Automation           Neil Cherry             ncherry_at_home.net
http://members.home.net/ncherry                         (Text only)
http://meltingpot.fortunecity.com/lightsey/52           (Graphics)
http://linuxha.sourceforge.net/				(SourceForge)
Received on Sun Aug 13 2000 - 13:38:14 BST

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