At 01:56 AM 8/22/1999 +0100, you wrote:
>>
>> Hi. I just acquired a Rainbow (haven't seen it yet, so I don't know
>> many specifics) but it has a color monitor and the guy said he also
>> had a touchscreen attachment for it.
>
>I've never heard of a touchscreen for the Rainbow, and I suspect,
>therefore, that it's a 3rd party thing.
>
>
>>
>> Anybody have pointers to where I can find out a little more about
>> this beast? The guy I'm getting it from told me it was working the
>
>I can tell you a little about the hardware. The motherboard contains 2
>processors (8088, used for CP/M 86 and MS-DOS, and a Z80, used for CP/M
>80), 128K (normally) of RAM, BIOS ROMs, a text-only video output
>(essentially the video circuit from a VT100), a couple of serial ports
>(one for the 'comms' (modem), one for a printer -- note the DB25 on the
>back is _not_ a parallel port), keyboard interface, and a lot of TTL
>glue. There are no expansion slots as such, but there are connectors to
>allow up to 4 boards to be fitted on top (each board has a particular
>position that it goes in).
>
>All machines have the RX50 (floppy) controller down the RHS. This is a
>Western Digital 1793 chip + support logic
>
>At the front left you'll have a 'colour card'. This is complex. It's got
>an NEC 7720 graphics coprocessor on it, along with 64K of video RAM,
>colour look-up table and more TTL glue. This is needed if you have a
>colour monitor in the system, but you can also use it with a mono monitor
>(to give bitmapped graphics, since the 'bow motherboard video is
>text-only).
>
>Behind that you might have a RAM card. There are 2 versions of this (at
>least). The older one is a plain 192K card. The later one will take up to
>3 banks of chips, either 64K in a bank or 256K in a bank (any mix). Yes
>you can have 896K of RAM in the machine.
>
>Behind that, across the back of the machine is the 'general purpose'
>expansion slot. The 2 connectors for this have just about every signal
>you could want on them. The most common card to find here is the hard
>disk controller (WD1010 + support chips), which links to an RD51 (10
>Mbyte MFM drive, probably an ST412). There was also a comms card that
>went here, but I've never seen it.
>
>The unit can be dismantled without tools [1]. Under the sides of the case
>are 2 little catches that you slide forwards and flip out to release the
>cover, which then lifts off. On top of the chassis are the drives
>(there's always an RX50 in the RH bay, and sometimes another RX50 or an
>RD51 in the LH bay). You can remove the drives by unplugging the cables,
>releasing the spring catch under the front edge of the drive, and
>sliding it out.
>
>Across the back of the upper chassis is the PSU. To get that out, unplug
>the power cables from the motherboard, drives, and fan/switch assembly,
>release the clip on the left end and swing it up and out.
>
>To remove the 'logic module' (motherboard and all the cards), unplug the
>power cable (thick ribbon cable) and the drive cables from it (there's a
>hole in the rear right of the chassis). Loosen the 4 black thumbscrews at
>the back, and slide the cards out of the back of the machine. You can
>frob the clips on the standoff posts and unplug the cards from the top of
>the motherboard.
>
>[1] I really have never seen the point of such cases. You need a
>soldering iron, logic analyser, etc to fix the machine anyway, so having
>a screwdriver is no big problem. And anyway, to take some of the Rainbow
>modules apart (like the PSU), you do need screwdrivers.
>
>The keyboard is a plain LK201. The colour monitor is a VR241 (plain
>TV-rate sync-on-green). You'll get a cable with a DA15 on one end (goes
>into the connector on the back marked 'video', and a box on the other end
>with 3 pigtails/BNCs (to go into the monitor) and an RJ11 (for the
>keyboard cable).
>
>The RX50 disk drive is strange. It's 2 drives in 1, sharing a common
>spindle motor, head stepper, etc. The top disk (drive A IIRC) goes in the
>normal way up.. The bottom disk goes in upside-down. If you have genuine
>DEC RX50 disks, then you line up the orange arrow on the disk with the
>orange line on the front of the drive.
>
>If you want to look inside the RX50 (and you should - once....), take it
>out and take out the 4 screws on the mounting skid on the bottom. The
>metal can then slides off backwards. Dismantling it further is possible,
>but it's not that easy. (I've done it, though, and got it back again).
>
>
>-tony
>
>
>
Tony, you should be charging us tuition, but I am glad you'r not.
Regards
Charlie Fox
Charles E. Fox
Chas E. Fox Video Productions
793 Argyle Rd. Windsor N8Y 3J8 Ont. Canada
email foxvideo_at_wincom.net Homepage
http://www.wincom.net/foxvideo
Received on Sun Aug 22 1999 - 07:02:26 BST