View Profile: Eudimorphodon - Vintage Computer Forum

February 26th, 2021, 03:28 PM

Eudimorphodon replied to a thread Model 3 video output. in Tandy/Radio Shack

The Model III's basic scan frequencies are roughly NTSC compatible, but the machine uses a really slow dot clock for its 64 column (512 dot wide)...

10 replies | 163 view(s)

February 25th, 2021, 07:49 PM

Eudimorphodon replied to a thread Printing from an old computer using a new USB printer in Vintage Computer Hardware

My point was that unless you pay someone to put it together for you a raspberry Pi or anything else (and I guess I got confused by the repeated...

22 replies | 332 view(s)

February 25th, 2021, 07:14 PM

Eudimorphodon replied to a thread Printing from an old computer using a new USB printer in Vintage Computer Hardware

Have to admit I'm left scratching my head exactly how buying a single-board computer automatically helps with this situation. (Granted we have no...

22 replies | 332 view(s)

February 25th, 2021, 11:56 AM

Eudimorphodon replied to a thread End of an Era - Frys gone in General Off Topic

Looking back it feels like Christmas 2018 was their last Hail Mary attempt to pull back from the Event Horizon of the black hole that had been...

51 replies | 714 view(s)

February 25th, 2021, 11:08 AM

Eudimorphodon replied to a thread Printing from an old computer using a new USB printer in Vintage Computer Hardware

This question requires a lot more information to answer meaningfully. (The big one being the exact vintage and platform.) I've successfully played...

22 replies | 332 view(s)

February 10th, 2021, 12:36 PM

Eudimorphodon replied to a thread 8086 based IBM compatible PC schematics in PCs and Clones

You'll probably need to bake your own BIOS if you leave out DMA. Bad suggestion: I think there's a disassembly of the original Tandy 1000 BIOS out...

17 replies | 1294 view(s)

February 10th, 2021, 12:30 PM

Eudimorphodon replied to a thread 8086 based IBM compatible PC schematics in PCs and Clones

This is off the top of my head, but I'm reasonably certain that with the 808x all addresses are byte-sized, which means that: * 16-bit...

17 replies | 1294 view(s)

February 10th, 2021, 08:37 AM

Eudimorphodon replied to a thread Looking for very special portable pc with color monitor in Later PCs

The Compaq's monitor is indeed not composite, it has an analog video line for the grayscale and separate sync lines. But for the record, the reason...

12 replies | 509 view(s)

February 8th, 2021, 08:37 AM

Eudimorphodon replied to a thread Looking for very special portable pc with color monitor in Later PCs

Shadow mask pitch is also a significant factor when you get down to sub-13" color CRTs. Most tubes that small just can't physically quite do 640...

12 replies | 509 view(s)

February 5th, 2021, 03:26 PM

Eudimorphodon replied to a thread VT320 - Replace CRT with LCD? in DEC

Between the info on that page about making custom fonts for the terminal and pictures of the display showing pretty wide "scanlines" I think its...

17 replies | 863 view(s)

February 4th, 2021, 02:17 PM

Eudimorphodon replied to a thread VT320 - Replace CRT with LCD? in DEC

Does anyone know the specs of the video output of the VT320? Several sources repeat that its resolution is "800x500", but that doesn't vibe with the...

17 replies | 863 view(s)

February 3rd, 2021, 02:52 PM

Eudimorphodon replied to a thread Z80 DART used for keyboard? in Vintage Computer Hardware

I second this theory. The '374 is the "clocked" version of that type of latch, I suspect it's set up so it latches when it receives a "strobe" signal...

9 replies | 359 view(s)

February 2nd, 2021, 09:51 PM

Eudimorphodon replied to a thread A dumb (but obscure) Commodore PET video implementation question: Hardware cursor? in Commodore

Thanks! I’m actually kind of amazed how ‘easy’ it was to get honest-to-goodness PHI clock sync working for video, and I’m kind of proud of the...

27 replies | 1665 view(s)

February 1st, 2021, 03:07 PM

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

... it's sad, I'm actually considering the idea of using a 15ns 32kx8 SRAM as a keyboard converter for the Commodore hackclone project because even...

63 replies | 2421 view(s)

February 1st, 2021, 03:01 PM

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

I have vague memories of reading once that it was standard with TRS-80 key scans to read the "255" row (which is activating all the row lines at...

63 replies | 2421 view(s)

February 1st, 2021, 12:51 PM

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

I was mulling over the idea of using dual-port memory for a TRS-80 keyboard matrix converter instead of one of those analog matrix switches, but it...

63 replies | 2421 view(s)

February 1st, 2021, 12:39 PM

Eudimorphodon replied to a thread A dumb (but obscure) Commodore PET video implementation question: Hardware cursor? in Commodore

Update on the PET(-like) video card project: It's officially a computer now. As of Friday I can run an ancient version of the PETTESTER ROM I wrote...

27 replies | 1665 view(s)

January 30th, 2021, 09:34 AM

Eudimorphodon replied to a thread Alternative Font for IBM 5150 with MDA? in PCs and Clones

I think people get confused comparing the 6845 to more “complete” graphics chips like, I dunno, a Commodore VIC. *All the 6845 does with RAM* is...

19 replies | 829 view(s)

January 30th, 2021, 09:15 AM

Eudimorphodon replied to a thread Alternative Font for IBM 5150 with MDA? in PCs and Clones

Graftabl only works on CGA in graphics mode, IE, when using software mode to draw “pictures” of letters. CGA likewise doesn’t actually support...

19 replies | 829 view(s)

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