phil@eos.UUCP (Phil Stone) (02/08/89)
In a posting last week, I asked the greater body of net knowlege if it knew of any "reserved" use for the two removable panels on the back of the A2000, directly behind the processor slot. I have had no replies, so I'm going to assume that these panels are fair game for the project I have in mind - a built-in MIDI port and additional serial connectors, switch selectable. I've run into a couple of snags on this one. First, I assume there is a seperate technical reference manual for the 2000. What's the quickest way to get one? Is it in bookstores? Maybe the answers to the following questions are in there, but bear with me as I don't have a copy yet. I was hoping to use the internal serial connector, but it appears to be a weird copy of the A1000 serial port, and therefore does not bring -12v out (I could use +-5v for the MIDI interface, but not for the 4066 analog switches I want to use for port selection - RS232 levels being +-12v on the Amiga, as far as I can tell). Anybody know of a good place not too far from this area in the 2000 to grab -12v? Finally, how critical are the light brown components that seem to straddle every line that leaves the A2000 for the outside world? I would assume they are EM filters of some kind, no? If they are critical, where does one find them - I've never seen anything like them in the electronics catalogs I peruse. If I can solve these difficulties, I plan to shoot a PC board for the MIDI interface (design based on an Electronic Musician schematic) and I will make the layout and plans available to the net somehow. Is anybody at all interested in a cheap, internally mounted MIDI interface? P.S., please don't tell me to get (or wait for!) a multi-serial board - I'm looking at cheap solutions here, and I don't need simultaneous use of many serial devices, just easily switchable access to several outputs.
perry@madnix.UUCP (Perry Kivolowitz) (02/10/89)
In article <2550@eos.UUCP> phil@eos.UUCP (Phil Stone) writes: >Finally, how critical are the light brown components that seem to straddle >every line that leaves the A2000 for the outside world? I would assume they I'm sorry Phil. But ``little brown components''? Are you really up to doing a design? (no offense intended) -- Perry Kivolowitz, ASDG Inc. ARPA: madnix!perry@cs.wisc.edu {uunet|ncoast}!marque! UUCP: {harvard|rutgers|ucbvax}!uwvax!astroatc!nicmad!madnix!perry CIS: 76004,1765 (what was that about ``giggling teenagers''?)
phil@eos.UUCP (Phil Stone) (02/11/89)
In article <481@madnix.UUCP> perry@madnix.UUCP (Perry Kivolowitz) writes: >In article <2550@eos.UUCP> phil@eos.UUCP (Phil Stone) writes: >>Finally, how critical are the light brown components that seem to straddle >>every line that leaves the A2000 for the outside world? I would assume they > >I'm sorry Phil. But ``little brown components''? Are you really up to doing a ^^^^^^ (sic) >design? > >(no offense intended) Oh, none taken, you pompous twit (no offense intended). I asked an honest question about a component I have never seen in 10 years+ of building (admittedly simple) electronics projects; instead of making this snide remark, would it have been too much trouble to answer the question, Perry? Can someone, perhaps from a slightly less exalted position of expertise, give me a straight answer on this? Phil Stone (phil@eos.arc.nasa.gov OR phil@eos.UUCP)
hah@inteloa.intel.com (Hans A. Hansen) (02/13/89)
$In article <2550@eos.UUCP> phil@eos.UUCP (Phil Stone) writes:
$Finally, how critical are the light brown components that seem to straddle
$every line that leaves the A2000 for the outside world?
$
$ Phil Stone (phil@eos.arc.nasa.gov OR phil@eos.UUCP)
The components that I think you are refering to are either the .001uF RFI/EMI
filter caps or the filter inductor ferite beads/or/resistors. These components
form either a R/C or L/C I/O filter to help our favorite computer pass
FCC class B, (Home use), not to mention VDE class B and all of the other
EMI watch dog agencies.
Hans NES Inc.