View Profile: blackepyon - Vintage Computer Forum

Yesterday, 07:42 PM

Eudimorphodon replied to a thread Composite color artifacts: made by design or happy coincidence? in PCs and Clones

The details give me a headache, but the long and short of it is the circuitry that has to trap out the narrow bandwidth chroma pulses and compare...

12 replies | 146 view(s)

Yesterday, 07:22 PM

Eudimorphodon replied to a thread Composite color artifacts: made by design or happy coincidence? in PCs and Clones

But the chroma data isn’t shoved into the back porch, only the color burst lives there. (Which is the sync/phase reference for the chroma data...

12 replies | 146 view(s)

Yesterday, 04:08 PM

Eudimorphodon replied to a thread Composite color artifacts: made by design or happy coincidence? in PCs and Clones

It's *possible* in CGA's case that IBM never actually thought of it and the fact that the hardware is capable of it is a happy accident resulting...

12 replies | 146 view(s)

Yesterday, 11:22 AM

Eudimorphodon replied to a thread Adding a CF card slot to a 5170 without wasting an expansion card bay? in PCs and Clones

A stock 5170's going to have an MFM + FDC board in it, not IDE, of course. But if you put a generic IDE/FDC card in there and want to just play the...

18 replies | 331 view(s)

January 14th, 2021, 03:09 PM

Eudimorphodon replied to a thread Adding a CF card slot to a 5170 without wasting an expansion card bay? in PCs and Clones

Just tossing this out there: they make IDE-to-SD and even IDE-to-Micro-SD boards that you could cable up instead of a CF adapter if you want...

18 replies | 331 view(s)

January 13th, 2021, 06:30 PM

Eudimorphodon replied to a poll System architecture for a Z380 TRS-80 compatible. in Tandy/Radio Shack

What are you planning to use for the video output hardware? And keyboard input, so far as that goes. (Interface to an actual matrix, or some kind of...

8 replies | 133 view(s)

January 13th, 2021, 05:50 PM

Eudimorphodon replied to a thread 2021 Vintage plans, and 2020 lessons learned. in General Vintage Computer Discussions

So, my list for 2021 shakes out something like this: Build a complete "working" computer based on the video dingus I've been futzing around with...

1 replies | 84 view(s)

January 13th, 2021, 06:58 AM

glitch replied to a thread SCA-80 Female to IDC-50 Male Adapter Design in Vintage Computer Hardware

Yeah, I typically grab them off eBay when I need them. Someone always has some NOS in retail packaging, and of course used ones are usually around...

3 replies | 54 view(s)

January 12th, 2021, 05:46 PM

Eudimorphodon replied to a thread Dr. Suding questions in General Vintage Computer Discussions

... so, in other words they successfully copied the *behavior* of the “canonical” 8080 accurately with the Z80. That says nothing about the hardware.

21 replies | 373 view(s)

January 12th, 2021, 04:45 PM

glitch replied to a thread No Name Computers CPU-Z80-IEEE Info in S-100

Thanks Herb! I didn't realize there was a non-corrupted version of the document in the ZIP archive! I assumed it was the same as the contents of the...

6 replies | 1372 view(s)

January 12th, 2021, 01:58 PM

Eudimorphodon replied to a thread Dr. Suding questions in General Vintage Computer Discussions

Electrically the 8080 and the Z80 aren't very much alike at all. The 8080 has an 8-bit ALU <strike>and a multiplexed address bus</strike>(*), the...

21 replies | 373 view(s)

January 12th, 2021, 10:24 AM

Eudimorphodon replied to a thread Dr. Suding questions in General Vintage Computer Discussions

Grrr. That one rankles me every time I see it. I understand he's a nice enough guy and means well, but he should know better. Re: the "slow scan...

21 replies | 373 view(s)

January 11th, 2021, 03:52 PM

Eudimorphodon replied to a thread Do VGA monitors distinguish between NTCS and PAL? in PCs and Clones

Here's a mind-numbing cross reference of Commodore 1080/1084 family monitors. The vast majority of the individual SKUs supported both analog and CGA...

12 replies | 315 view(s)

January 11th, 2021, 10:57 AM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

My TRS-80 Model I came with one of those fabric glare filters stuck to it. I did inexplicably like it a lot; obviously it doesn't actually help with...

21 replies | 569 view(s)

January 11th, 2021, 05:28 AM

glitch replied to a thread Battery problem w/ Dallas DS1287 in Later PCs

You're not kidding! We adjust most of our older equipment in-house, just because it's so difficult to find a calibration shop that does good work...

24 replies | 475 view(s)

January 11th, 2021, 04:47 AM

glitch replied to a thread Battery problem w/ Dallas DS1287 in Later PCs

Funny how often Internet experts are *certain* something won't work without having tried it for themselves, eh? :p "But it simulates that way!" ...

24 replies | 475 view(s)

January 10th, 2021, 07:49 PM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

Don't run video modes that the attached monitor doesn't natively support. I mean, the reason it faked shades of gray like that was because if you...

21 replies | 569 view(s)

January 10th, 2021, 07:46 PM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

The idea of such a thing did actually occur to me, but here's the painfully obvious problems that to my mind prevent it from working on even a...

21 replies | 569 view(s)

January 10th, 2021, 05:05 PM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

I'm pretty sure the placebo affect was depressingly significantly responsible for the relief people claimed to feel after sticking all kinds of...

21 replies | 569 view(s)

January 10th, 2021, 04:06 PM

glitch replied to a thread Battery problem w/ Dallas DS1287 in Later PCs

No definite timeline, I PMed you about getting a prototype version though. Heh, I laid out the GW-1225-1 due to having a piece of test...

24 replies | 475 view(s)

January 9th, 2021, 08:03 PM

Eudimorphodon replied to a thread Address decoder revisited in S-100

That was a cut-and-paste for an earlier version that was designed to blow PROM "fuses" made out of barbed wire for programming the ENIAC?

12 replies | 345 view(s)

January 9th, 2021, 04:47 PM

Eudimorphodon replied to a thread Address decoder revisited in S-100

Heh. GALASM so far as I can tell is an intentional clone of PALASM; from some brief digging on the latter the syntax looked almost identical to me;...

12 replies | 345 view(s)

January 9th, 2021, 03:31 PM

glitch replied to a thread Battery problem w/ Dallas DS1287 in Later PCs

DIP packages, a DIP package DS1285 is what's inside a DS1287. They were available for a while. I have a very small stock of NOS DS1285s in DIP for...

24 replies | 475 view(s)

January 9th, 2021, 11:42 AM

glitch replied to a thread Battery problem w/ Dallas DS1287 in Later PCs

There's two pins on each side, and they're not folded over, they're in castellated holes. We epoxy the circuit board to the DS1285/DS12885 before...

24 replies | 475 view(s)

January 9th, 2021, 10:47 AM

glitch replied to a thread Battery problem w/ Dallas DS1287 in Later PCs

Yeah, if it doesn't work with a 12885, a 12887 definitely won't do it -- there's a 12885 inside every 12887. I don't agree either, see below....

24 replies | 475 view(s)

January 9th, 2021, 06:25 AM

glitch replied to a thread Battery problem w/ Dallas DS1287 in Later PCs

On the motherboards I've seen with a Dallas module and a battery header, there was support circuitry around the Dallas module that looked like it...

24 replies | 475 view(s)

January 8th, 2021, 11:21 PM

Eudimorphodon replied to a thread Address decoder revisited in S-100

I recently did a video about using GALASM, a simple open source logic compiler with pretty elementary syntax, to do combinatorial and registered...

12 replies | 345 view(s)

January 8th, 2021, 10:00 AM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

Pretty sure the grayscales on the Deskpro monitor are real instead of interframe PWM so you're probably good unless the basic refresh rate is an...

21 replies | 569 view(s)

January 7th, 2021, 02:21 PM

Eudimorphodon replied to a thread Writing Mac 800kB disks in Later Apple (68000+ based machines - Mac, Lisa, etc.)

According to this datasheet for an early Sony mechanism it did have a 600 RPM motor (they intended it to be used with 500kbs controllers, not the...

29 replies | 786 view(s)

January 7th, 2021, 01:29 PM

Eudimorphodon replied to a thread Writing Mac 800kB disks in Later Apple (68000+ based machines - Mac, Lisa, etc.)

Apple had a massive, raging case of NIH Syndrome in the early 80's. Remember, the 3.5" Microfloppy drive only ended up in the Mac at all because of...

29 replies | 786 view(s)

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