Portable Commodore 64

[Ethan Dicks]

On 4/21/06, Roy J. Tellason <rtellason at blazenet.net> wrote:
> On Thursday 20 April 2006 10:37 am, Philip Pemberton wrote:
> > In message <200604201407.k3KE7RrK018110 at floodgap.com>
> > Are there any custom ICs in there - custom defined as "not found in a
> > garden-variety breadbox Commodore 64"? Hardware-wise, how do the two
> > machines compare (besides the obvious "the SX64 has a built in monitor and
> > disc drives")?

Disc drive, singular.  There apparently was a plan to offer a
dual-drive unit (DX64), but the PSU wasn't up to it (and perhaps the
passive cooling as well).

> > I know there's the SID and VIC; I was wondering if the drives were
> > implemented as "guts of a 1541 strapped to the chassis" or custom ICs
> > integrated onto the mainboard.

The maintenance manual should be on funet, but ISTR the disk drive is
implemented on its own board, but is not exactly the same board out of
a 1541 (based on, yes, same part, no).

> One of the ROMs is a different part number,  which gives slightly different
> default screen colors,  but I know that in repairing one the ROM out of a C64
> can also be used.  There are also differences in the drive,  for sure,  but
> it's been long enough since I've been into one that I don't remember what
> those are off the top of my head.

Yeah...  think the differences only matter for fast loaders and such. 
The trickiest thing I ever ran on an SX64 was a later version of the
Infocom interpreter that asked if you had a real 1541 or not (so it
could play tricks with the drive-to-CPU comms - a software speed
loader, IIRC).

The C-64 ROM works in an SX64, but, of course, the cassette stuff
doesn't, since the SX64 doesn't provide a cassette port.

>  I do have a service manual for those around here someplace,  I used to fix
> them,  along with a lot of other C= stuff...

http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/c64/sx-64/index.html

(apparently funet has been relocated...)

> Anybody looking for any c= parts?  Drop me a note off-list.

Doing fine there - one of these days, I should go through my stacks of
stuff and offer it up- I have several tackle-boxes of upgrade parts
from that C= dealer... ROMs (all of which are imaged on funet AFAIK),
various rev video chips, etc.   Never enough time...

-ethan