grusin@boulder.Colorado.EDU (GRUSIN MICHAEL) (12/17/90)
I'm building an expansion chassis for all the items that are currently plugged in the side of my Amiga 1000, to keep them out of the way, (some I have built myself and don't have cases), and to provide an additional power supply for them. (The 1000's power supply is starting to complain about the load =). The question: I'm not quite sure how to hook up the power supply for the expansion cards; I know the grounds need to be common, but do the actual power lines (-12,-5,+5,+12) need to be (or should they be?) common with the computer's supply? If it doesn't matter, (or will work both ways), what is the general practice for this situation? (btw, thanks to all who replied to my thermoelectric module question, it was a great help!). Thanks in advance, - Mike Grusin (grusin@tramp.colorado.edu)
ardai@teda.UUCP (Mike Ardai) (12/19/90)
In article <1990Dec17.004840.22780@csn.org> grusin@tramp.Colorado.EDU (GRUSIN MICHAEL) writes:
[ Building an expansion chassis for an Amiga and wants to know how to hook
up the new supply]
Just hook up the grounds in common between the 2 supplies, and leave the
other voltages separate. You should never hook supplies in parallel unless
they were designed to be, since if their voltages are not *identical*, one
will try to drive the other. You might want to use a relay (watch the
contact current ratings), driven by the Amiga's old 5V supply to cut out
the new supply's outputs in case the Amiga could be powered off while the
expansion chassis is on. Most ICs don't like having their pins driven
without Vcc.
/mike
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\|/ Michael L. Ardai Teradyne EDA East
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