The Apple II Yellowstone Floppy Interface(nicole.express)

86 pointsby zdwvor 4 Jahren20 comments

The Apple II Yellowstone Floppy Interface

https://nicole.express/2022/my-yellowstone-vacation.html

20 comments

sbf501vor 4 Jahren

> That’s right, this is actually a look at a product being sold at the time of this writing, the Yellowstone controller card:

I'm not surprised. I shelled out $80 bucks for a null modem RS232 cable and two packs of Verbatim 5.25" floppies, sealed, from the 1980's, so that I could get my Apple //e running again. Ironically I never knew the SuperSerial card could turn the Apple into a dumb terminal: now I can copy Apple //e disk images from my Mac, via serial, to the target 5.25" drives. I mean, it's obvious now, but it never occurred to me in the 80's.

The design of this card is better too because it has plug polarity. I had to replace a buffer chip on one of the drives because the original Apple ribbon cable socket didn't have a polarity (or collar) and I accidentally installed the cable shifted right one pair of pins. Powered up, heard a loud crack, and when I opened the drive, there was a 14-pin DIP cracked in half and blackened.

Also, that "Total Replay" screen is hilarious. What a mashup.

CamperBob2vor 4 Jahren

I mean, it's obvious now, but it never occurred to me in the 80's.

What's really going to bake your noodle is when someone tells you your Apple had a 1200-baud modem built in at the factory.

sbf501vor 4 Jahren

Huh? Where?

EvanAndersonvor 4 Jahren

The cassette interface is a type of modem. It's not a telephone modem, but it is modulating and demodulating digital data to/from analog.

CamperBob2vor 4 Jahren

Interestingly, all it takes to turn it into a telephone modem is a hybrid network from an old phone and a couple of LM386-grade audio amps.

Not exactly Bellcore-202 spec, but it was good enough to send Strip Poker pics to a friend across town.

sbf501vor 4 Jahren

You have absolutely baked my noodle.

/golf clap/

skissanevor 4 Jahren

The cassette interface.

EvanAndersonvor 4 Jahren

And a makeshift audio digitizer!

user3939382vor 4 Jahren

I have an Apple IIc but I have a hard time finding 5 1/4s for it. The ones I do find seem like they almost never work, maybe because of age. I'm not sure.

If anyone that's into this type of retro computing has any tips for getting reliable IO/disks with these old machines I would appreciate it.

toast0vor 4 Jahren

One thing to be aware of is high density floppies are unlikely to work. You've got to make sure you get double density (aka low density, but I guess there was some abandoned standard that was lower than double). I've got a bunch pulled from that one time my dad broke our Tandy 1000 TL/2's floppy port and the 3.5" ds/dd drive stopped working, but we still had the 5.25" ds/dd drive running, and a lucky find at WeirdStuff. But I've got the problem that even though the disks are double sided, I can't use the backsides because I don't have a notcher and I'm not using scissors. :( Also, something happened to my monitor recently, and now it only blows fuses and doesn't display things anymore :((

If you're in the Seattle area, email me (on profile) and I can give you some disks, but I'm not gonna mail them.

sbf501vor 4 Jahren

Here is what I purchased:

https://retrofloppy.com/products/#BlankDisks

They seem to be working fine. I used 5 out of 20 so far.

StillBoredvor 4 Jahren

There are various modern disk interfaces that can be plugged in as alternatives.

BMOW, also has a floppy emulator you plug into the floppy controller which emulates the drive+disk using SD cards.

https://www.bigmessowires.com/floppy-emu/

I have a fairly old CFFA

https://dreher.net/?s=projects/CFforAppleII&c=projects/CFfor...

as well, its a pretty solid HD emulator as well.

There shouldn't be a problem using older floppy disks if you can get ones that actually are for apple ][s and C64's rather than the later higher density ones used by PCs/etc.

kralljavor 4 Jahren

https://www.floppydisk.com/5point25 is, as far as I can tell, the only reliable seller of floppy disks left on the planet.

zackbloomvor 4 Jahren

> I went out of my way to feed the Apple ][ video into the luminance pin of an S-Video port for this segment to make the text more readable at the expense of color.

I found this to be the most interesting part of the whole post, I'd love to see a schematic of how that works.

kralljavor 4 Jahren

The schematic would just be a wire connecting two pins.

    RCA             Mini DIN
    __________________________
    COMP o--------o LUM
          --------o CHROM 
     GND o--------o GND

S-Video has two pins (plus ground): luminance and chrominance. Composite has only one pin (plus ground). A composite video signal is a hack (for backwards compatibility with B&W TV) that has both of these signals (and some timing signals, called "sync", which happen outside the visible area of the image) combined together into a single "composite" waveform. De-composing the two signals is what causes color bleed and color artifacts with NTSC color images: it's not easy for a monitor to reverse the math, especially on abrupt brightness edges (like the kind computer pixels are prone to causing, with their decidedly discrete color transitions), since they look an awful lot like the color carrier shifting phase.

S-Video is exactly the same two visible signals as a composite image, but the color data gets its own dedicated pin. So, if you send a black and white composite signal on the luminance pin, and no signal at all on chroma, you get a completely clear B&W picture output, with 0 color bleed (since there is no color information).

duskwuffvor 4 Jahren

Some early computer monitors had a "mono/color" switch which could disable chroma separation. Set to "mono" for text mode; "color" for games. :)

nicole_expressvor 4 Jahren

It's pretty easy to get a breakout cable for chrominance and luminance separately into an S-Video port; at that point I just plugged in the Apple II's output into luminance and left chrominance unconnected.

This works particularly well on the Apple II because all of its color actually comes from creating dot patterns that cause luminance to interfere with decoding of chrominance, it has no "real" chrominance signal.

scarface74vor 4 Jahren

I think my Mac LCII/Apple //e card/5.25 disk drive combination is still in a closet somewhere at my parents house. I know my collection of 5.25 disks are still in my old bedroom under a desk.

I keep meaning to get my setup and seeing if I can get it up and running. But then again, I keep struggling with why? For nostalgia, I can find most of the images on the internet and run them on an emulator.

Gracanavor 4 Jahren

That’s a cool machine to have. Hopefully the motherboard hasn’t been corroded by a leaky battery and/or capacitors. That’s the common fate of 90s Macintoshes. It’s often repairable, but it can take considerable effort to rework and repair a board with traces and vias and IC legs eaten by acid.

scarface74vor 4 Jahren

And I also had a copy of SoftPC with it to run my DOS based compilers for college.

Ironically enough my next computer two years later was a PPC 6100/60 with a DOS Compatibility card. That should also be at my parents house somewhere.