C506634@UMCVMB.MISSOURI.EDU (Eric Edwards) (09/03/90)
In Message-ID: <Aug.31.11.18.41.1990.3118@pilot.njin.net>
limonce@pilot.njin.net (Tom Limoncelli) exagerates just a little.
>The CBM power supply is speced to handle the A500, the A501 Memory
>Expansion and EXACTLY 1 external floppy drive. This was told to
>developers from day one. There are EXACTLY 0 amps remaining after
>this configuration is used.
Correct, but incomplete. The A500 power supply is designed to A500, the
A501 memory expansion and the A1010 floppy drive. Don't know about A501
clones but the average 3d party floppy drive uses about 1/2 the power of
the 1010. So you could have two exeternal drives and still be clear.
>But you say: "OK! I'll buy a bigger power supply! More amps for everything."
> Ok. Now each component is getting the right amount of
>electrons, but are you sure? Well, lets assume that you are an EE and
>you are sure. How do all those electrons get to those components?
Through a simple line filter and not much else.
>the electrons to heat. They get so hot that the plastic case can
>melt. There is just enough ventilation in the A500 to support normal
>operation. Don't push it. If you don't melt the plastic case you are
There are no resistors in the power input circuitry and I rather doubt the
line filter generates much heat.
> Sort of. In the specs it says that daisy-chaining off the
>expansion slot it NOT allowed. You either add one device or a
>well-built expansion box.
Becuase of problems with the interaction of daisy chained componanants on
the A1000. I would certainly recomend that someone palnning on daisy
chaining test it first in the store becuase it you can't be sure it will
work. But you can be sure it won't destroy your computer.
> I reply, "I have personally never recommended that anyone
>purchase an A500. If you want to save money buy an A2000. If you
>want to save time (by reducing hassle) buy an A2000. You save twice."
Concider that an A500 + small Hardrive + small Memory Expansion is only slightly
than a A2000 alone. If further expasion fits in the "someday, I might..."
catagory it's hard to justify the A2000. Upgrading from an A500 or A2000
to an A3000 costs the same.
Eric Edwards c506634 @ : "See computer history first hand. Dial up your :
Inet: umcvmb.missouri.edu : local IBM mainframe" 7 bits :
Bitnet: umcvmb.bitnet : |3090| -----------|Amiga| :swarren@convex.com (Steve Warren) (09/07/90)
In article <900902.171843.CDT.C506634@UMCVMB.MISSOURI.EDU> C506634@UMCVMB.MISSOURI.EDU (Eric Edwards) writes: >> Sort of. In the specs it says that daisy-chaining off the >>expansion slot it NOT allowed. You either add one device or a >>well-built expansion box. > >Becuase of problems with the interaction of daisy chained componanants on >the A1000. Speaking of which, I've been wondering about something. On the 1000 one problem I've seen mentioned was that most expansion chassies did not buffer up the bus signals before connecting them to the expansion backplane. This meant that most of them did not perform properly. Now I've been wondering, wouldn't it be relatively simple to piggy-back buffers on-top of the SOTS driver chips on the A1000 motherboard? This would double the drive current being provided to multiple cards in an expansion chassis. The one possible problem this might cause would be to mess up timing by adding too much to the load of the internal circuits on the motherboard that are driving these buffers. I would not expect this extra delay to approach the kind of delay that would be added by adding buffers in series externally to the A1000 (in the expansion-chassis), however. What do you think? -- _. --Steve ._||__ DISCLAIMER: All opinions are my own. Warren v\ *| ---------------------------------------------- V {uunet,sun}!convex!swarren; swarren@convex.COM