> From: Don Maslin <donm(a)cts.com>
> Drive select - a choice of 1/2/3 - is determined by the programmable
> shunt at location 1F. Installing a DIP switch is a much handier means
> of selection. Configured for multiple drive installation, MX should be
> open, HS shorted, and only the desired DSx shorted.
Okay, that's clear.
> Termination is by a 150Ohm resistor DIP.
Thanks. There's an empty 14-pin DIP socket adjacent to the above-mentioned
shunt, so I'd guess this is drive is missing the terminator.
> The power connector is the same as used on more modern 5.25" floppy
> drives with pin-1 at 12VDC, pin-2 12V return, pin-3 5V return, and pin-4
> 5VDC. Pin one is identified on the component side of the PCB.
Thanks again, this drive does not have a "standard" power connector such as
is found on late-model 5.25" drives -- it only has a four-pin header. Not
being familiar with the SA400, I wasn't sure if this header was normal for
this drive, or if it was some user's modification.
Fred Cisin wrote:
> Termination is required on the last drive on the cable. Lack of proper
> termination can make for flaky operation, but will not generally
> prevent it from working.
Sure, but I didn't know the details of the terminator since it's missing on
this drive.
> I've never seen a factory switch on the front of one. Are you sure that
> that wasn't a user added switch, such as one to override the
write-protect
> for flippies?
Not sure at all, but it certainly is professional-looking. Due to my
inexperience, I've never seen an SA400 before and I thought there might
have been variations.
Thanks to both of you for the information.
Glen
0/0
Wayne Stewart did a PDF conversion--not just a scan--of
the manual for the Apple II Programmers Aid ROM. There
are a few typographical errors but it is very good.
It is about 278KB. E-mail me if you want a copy.
The empty ROM socket in the Apple II at addresses $D800-$DFFF
never had an official Apple ROM but there were some third party
ROMs such as the Inspector and the Senior PROM. In the Integer
BASIC disk file on the DOS 3.3 system masters that area is
filled with the Applesoft BASIC code from the same range of
addresses.
--
Paul R. Santa-Maria
Monroe, Michigan USA
> From: Fred Cisin (XenoSoft) <cisin(a)xenosoft.com>
> The original post on this thread mentioned not having a "standard" floppy
> power connector (Molex), and not knowing the pinout of the
> connector(s).
Upon very close examination I can see some stray flux around the solder
connections to the four-pin header (which is present instead of the Molex
connector), so my guess is that the original connector was removed by a
user. The additional write-protect switch, however, is a *very*
professional installation.
> Could it be that his SA400 is an aftermarket drive for
> Apple (or something else), where the Shugart board was replaced by
> something weirder?
Possible. The drive came from a home-built enclosure which also contained
a home-made PSU and ZX81-compatible keyboard (no ZX81 board, though :<( )
Also, since all of my other systems use 40-track drives, I doubt I'll ever
have any use for this thing. Are they still commonly available? If not, I
may hang on to it "just in case." Otherwise, it's probably off to eBay
unless someone on this list wants it and is willing to pay postage.
Later --
Glen
0/0
At 06:09 PM 10/28/02 -0800, dwight elvey wrote:
>Hi
> Actually, I was bummed. ...
> I had a Poly-88 setup but I think only one in 10 noticed
>and even then, I think only 2 in those ten knew what it was.
I spotted it, and I knew what it was. But how could you tell
that? Probably other people were the same.
> Of course, my display was all about tape recovery and not
>the Poly-88. I don't think, maybe, 5 people all together
>realized that.
That, I didn't spot. I noticed the waveforms on the wall, but amidst the
din (auditory and visual) it didn't register. I wish I had noticed,
though, since it is an area I want to spend some time working on one of
these years. Rather than letting it be lost to the moment, is there any
chance of you writing up your work and putting it online somewhere (even
posting it to this list and letting it get archived would work).
I've read a half dozen very terse summaries of emulators and such that do
this, but most work only on really clean tapes. They simply do some DC
correction, perhaps a bit of filtering, and then time zero crossings and
decode from there. Have you done something more sophisticated than
this? Some of the Sol tapes I've looked at are way too corrupted for such
a simple technique to work.
There are a lot of communication theory ideas that could be applied to the
problem directly; in addition, the file format is going to have some known
structure that could be used to help train the receiver and disambiguate
some cases.
I'd be interested to hear more.
-----
Jim Battle == frustum(a)pacbell.net
Hi all,
I've heard of the possibility to have a serial console connected to the
printer port of the DEC Professional series computers, and it is what
I'd ike to have.
Do you have any pointers to get it solved, or any hints ?
The pinouts schema could be the best for me.
Your help will be greatly appreciated.
Franco
----- Original Message -----
From: "dneprcomp" <dneprcomp(a)rmortho.com>
Newsgroups: comp.os.vms
Sent: Monday, October 28, 2002 7:20 PM
Subject: Free VAX
> The following items are free:
> 2 MicroVax II model DH-63003-E2 TK70 OS VAX IVMS ver. 1,7
> Terminal VT 220
> Tape Backup 8 mm
> Plotter Bruning model ZETA 8A.
> Location: Los Angeles
> If interested please call Yakov at 818-704-8198
>
>
Hi all,
I've heard of the possibility to have a serial console connected to the
printer port of the DEC Professional series computers, and it is what
I'd ike to have.
Do you have any pointers to get it solved, or any hints ?
The pinouts schema could be the best for me.
Your help will be greatly appreciated.
Franco
