Portable Commodore 64

[Roy J. Tellason]

On Friday 21 April 2006 01:25 am, Ethan Dicks wrote:
> 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 never saw one of those,  but heard rumors from time to time about them being 
sold in Canada,  or maybe in Europe.

> > > 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).

Yeah,  there were some significant hardware differences since in this unit 
everything worked off one power supply rather than the two separate supplies 
you'd have in a c64+1541.

> > 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.

See my other nearby comment about fixing that.  :-)

> >  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...

Hmm.

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