Questions tagged [hardware]

Retro hardware generally: boards, extension cards, power supplies, peripherals. Use more specific tags as appropriate; use [case] instead for enclosures.

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What contemporary hardware was available for the development of Atari 2600 (or other 2nd gen) games?

The Atari 2600, along with others like the Odyssey 2 or Intellivision, were among the first programmable home game consoles. They existed alongside personal computers like the Apple II and Commodore ...
David's user avatar
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3 votes
1 answer
355 views

Where can I find hardware details for the Philips VG-5000?

I'm interested in exactly what connectors the VG-5000 and what the pinouts are for them. Ideally, I'd like a full set of schematics for the machine.
cjs's user avatar
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59 votes
2 answers
23k views

What is this large device labelled 'Telefunken Datenspeicher' and how does it work?

We found this device in our school. Does anyone know what this can do exactly, and how it could work? We managed to input values into the bit storage on the top, but nothing more. Can we calculate ...
Poldi's user avatar
  • 591
3 votes
2 answers
251 views

Which S-100 systems supported both hard- and soft-sectored 8-inch floppies?

In the late 1970s to early 80s incompatible system software (i.e. MicroSoft Basic and CP/M 1.4) for S100 computers could be released in 8 inch, hard and soft sector, floppy disk formats. In that era ...
PDP11's user avatar
  • 710
10 votes
5 answers
6k views

When did the PC bus start slowing access to video RAM?

The PC architecture, from the original IBM PC onward, has always been designed around the idea that video memory will be on an expansion card. This was an unusual design decision; most 80s computers ...
rwallace's user avatar
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9 votes
2 answers
1k views

Atari SIO vs IEEE 488

When Atari was designing the 800 series of computers, they needed a way to connect peripherals. To comply with FCC regulations on RF emission, it needed shielded cables. To achieve low cost of entry ...
rwallace's user avatar
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9 votes
0 answers
256 views

Why must the Amiga 1020 disk drive be powered-on before and powered-off after the Amiga computer?

The Amiga 1020 was a 5.25" disk drive for use with the Amiga computer. Anecdotally, I suspect they are somewhat rarer these days because they were a less popular choice for a second drive back in ...
Geo...'s user avatar
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5 votes
0 answers
99 views

What documentation was provided with the Amiga 1020 disk drive?

The Amiga 1020 was a 5.25" disk drive for use with the Amiga computer. Anecdotally, I suspect they are somewhat rarer these days because they were a less popular choice for a second drive back ...
Geo...'s user avatar
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4 votes
2 answers
2k views

Gameboy Key Input Causes Crash

I made a Key Tester using the STDIO header included with GBDK. It works... Until it doesn't. All the keys register and print to the screen, except the Left(5) and Right(4) Directional Keys, which ...
OPM eStudio's user avatar
24 votes
3 answers
5k views

First time seeing this odd little PCB inside a Playstation 2; What is it for?

I have opened a few Playstation 2 consoles to fix or clean them so far and I have never seen this weird little board before. It is connected to where the ribbon cable for the front panel (power/reset ...
olliebulle's user avatar
5 votes
1 answer
357 views

Can the MC6850 ACIA signal that it wants to send data but not receive it?

I want use MC6850 ACIA for bidirectional communication, but I am not sure if I've understood it well. I want use an IRQ to interrupt an MCU when the ACIA receives data or has transmitted it. The MCU ...
gilhad's user avatar
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5 votes
0 answers
218 views

Where can I find a schematic of the AT&T KBD 301?

Where can I find a schematic of the AT&T KBD 301? I have an old AT&T 6300 (AT&T's rebrand of the Olivetti M24) but the keyboard (AT&T KBD 301) is not working. Many of the keys do work ...
user4574's user avatar
  • 399
21 votes
10 answers
9k views

Was there any computer since about 1960 without interrupt support?

The invention and spread of interrupts in the 1950s is reasonably well known but I am curious: were there any systems after which didn't support them?
chx's user avatar
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3 votes
0 answers
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Two Unknown Sony Corp Boards - Please identify

There are two Boards: The first one has Chips with the name "Sony 501 0C 185", "Sony 502 0J 043", "Sony 504 1B 002 504-3", "Sony 509 01 017 509-00", "Sony ...
I Ate Minecraft's user avatar
3 votes
0 answers
174 views

Troubleshooting Legacy Hardware and Software Issues on MS-DOS and Windows 3.11

I have an old PC with the following hardware components: Motherboard: AMI TITAN II EISA rev.D RAM: 48MB of 4 SIMM CPU: 154C Pentium (tm) BIOS: 711011596 HDD1: SCSI controller adapter through PCI (PCI) ...
CluelessENGR's user avatar
1 vote
0 answers
159 views

Defective Apple IIe motherboard

I have a PAL Apple IIe, put in service in 1982. Components C9, C12, C15, and C17 on the 820-0073-B motherboard are burnt out. I originally thought they appear to be power diodes, but seem to be 10 µF ...
Jochen's user avatar
  • 11
3 votes
1 answer
213 views

Do Z80 datalines need termination [closed]

If I am using a z80 can you just tie all data lines to the ROM 28c16 or do they need termination via 10k ohm resistors to ground?
Mwendt's user avatar
  • 31
4 votes
1 answer
133 views

Mac Plus refusing to read disks

OK, so I was gifted a Mac Plus a couple weeks ago, and finally got it up and running a couple days ago (had to wait for mouse and a couple lots of disks for it to arrive, since it came as just the Mac ...
Kaji's user avatar
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1 vote
0 answers
228 views

Why is my crystal oscillator (4 pin DIP 4 MHz unbranded from ebay) producing unusable clock signal waves? [closed]

I was trying to make a Z80 computer (I tried with Intel 8088 and failed because I am dumb) so I bought a 4-pin 4 MHz crystal(from here:ebay listing) and I tried to check the crystal by connecting it ...
Dragonite Brian 1024's user avatar
5 votes
1 answer
1k views

What sort of LCDs are used by the Game Boy/TI-83 calculator/etc.?

The Wikipedia article on the Game Boy lists the display as an STN display, whereas the ones for TI graphing calculators don't give any detail. However, even knowing that it's an STN display only ...
v-rob's user avatar
  • 857
11 votes
3 answers
832 views

TMS9918 - why have separate data-in and data-out?

Usually 8bit video chips interface with DRAM using: an address bus for rows and columns, a bidirectional data bus in the case of 1bit DRAM data-in and data-out pins are shorted on the same data line....
Valentino Miazzo's user avatar
13 votes
2 answers
1k views

What are the electrical properties of the EAR and MIC sockets on a ZX Spectrum, and can they be connected between machines?

I'm interested in the possibility of connecting two ZX Spectrum computers together using as simple an interface as possible. The ZX Spectrum has two mono audio sockets at the back labelled EAR and MIC....
knol's user avatar
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4 votes
1 answer
302 views

Can someone help me port the fat32 library used in the x16 to my homebrew 65c02? [closed]

A little background: As a retired electronics technician, (not engineer), I decided to design and build a 65C02 based computer. Only after building it did I realize how important advanced or ...
Carl's user avatar
  • 101
14 votes
1 answer
2k views

How did Altair 8800 interrupts work?

I'm playing around with building an Altair 8800 emulator in my free time in C#. I've read through the Operator's Manual many times in the past, and I'm refreshing my memory of late. I'm struggling to ...
ConnieMnemonic's user avatar
1 vote
0 answers
309 views

Was hardware scrolling patented?

One of the most valuable graphical features on early computers that had it, was hardware scrolling, that allowed the horizontal position of the screen to be adjusted by one or more pixels, thereby ...
rwallace's user avatar
  • 61k
5 votes
1 answer
401 views

Why does the VIC-20 have its cartridge area at a higher adress than the I/O area?

Why did the designers of the Commodore VIC-20 chose to put the main cartridge ROM area at $A000, beyond the character ROM area at $8000 and the I/O area at $9000? Flipping the two around, with the ROM ...
TeaRex's user avatar
  • 703
25 votes
1 answer
4k views

Why does the Commodore 64 have 4K of non-banked RAM at $C000?

I wonder why the Commodore 64 memory map was created as it was. Naively, it seems to be that it would have been more logical to put I/O and the character ROM at $B000 to $BFFF, have the ROMs in a ...
TeaRex's user avatar
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18 votes
5 answers
3k views

What is the most accurate way to map 6-bit VGA palette to 8-bit?

AFAIK VGA mode 13h palette has only 64 possible colors (6-bit) per channel. One obvious way to map those 64 colors to 256 colors is to multiply them by 4 (since 4 * 64 = 256): 8_bit = 6_bit * 4; This ...
tigrou's user avatar
  • 365
6 votes
0 answers
216 views

Where can I find information on old Kontron emulators?

Way back in the mid-80s, I worked as a programmer for the Apple II family, Commodore and Atari machines. I remember programming them using a big intimidating box branded Kontron stacked on top of my ...
ATL_DEV's user avatar
  • 382
9 votes
2 answers
2k views

Why did the Apple III have more heating problems than the Altair?

The Apple III was famously prone to overheating, to the extent that Apple advised customers to drop the machine a few inches onto the desk in the hope that this would knock chips back into their ...
rwallace's user avatar
  • 61k
0 votes
1 answer
117 views

Netronics Explorer 85 level A interrupt handling mechanism

I'm trying to understand how the RST 7.5 interrupt circuit works in the Explorer 85 level A, since in the i8085 the address jumped is located in 003CH (for level A there is no memory mapped here), but ...
Federico's user avatar
  • 153
16 votes
4 answers
3k views

Did anybody use PCBs as macro-scale mask-ROMS?

Early on, even fairly small ROM's were quite useful. For example, you could fit a minimal upper-case only font for a terminal into something like 256 bytes. And that's a scale that a human could lay ...
wrosecrans's user avatar
  • 2,264
4 votes
0 answers
363 views

Snack shipped with computer products [closed]

I remember that there was a company in the US that packed candy or snacks as a bonus in the shipping box with their products. They were well-known for this practice. I'm pretty sure the snack was ...
Dennis Williamson's user avatar
1 vote
1 answer
185 views

Why does my Mikrolab randomly freeze and unfreeze, and what can I do about it?

I've started using my Soviet Mikrolab KR580IK80 (a clone of the Hewlett Packard 5036A) again, and I've noticed some behaviour which it used to exhibit but now it seems more frequent. Basically after ...
harlandski's user avatar
  • 2,953
7 votes
3 answers
1k views

Sending video to Telerate 9" Green Monitor [closed]

I found an old Telerate green monitor at a thrift store and figured I could run my computer output through an HDMI -> AV converter with no problem, or a Raspberry Pi composite output signal. Turns ...
bitterlake's user avatar
3 votes
2 answers
395 views

When did CMOS processors become the fastest?

The earliest CMOS microprocessors (RCA 1802, HP Stirling RISC, et.al.) were slower than contemporaneous NMOS microprocessors and Bipolar logic computers. (IIRC, both the 1802 and the 6502 could be ...
hotpaw2's user avatar
  • 8,183
0 votes
1 answer
307 views

I have old hardware; what can I use it for? [closed]

I have two old pieces of hardware: a DVD drive and a hard disk, both from 2004, which I would like to use. I have a computer made for Windows 7, currently running Windows 98 which would probably run ...
Humancoder1123's user avatar
10 votes
1 answer
350 views

How did relay computers handle inductor flyback?

Many early computers were relay-computers. Like any other inductor, when the coil in a relay is shut off, the current through the coil continues to flow. This is a result of Faraday's Law of ...
DrSheldon's user avatar
  • 16k
3 votes
1 answer
650 views

How can I repair a sketchy video signal on a 1977 Pong unit?

I bought a 1977 Gracia Color Video Game TVG 432 (not much to be found online), image from 20th Century Video Games: And the unit works, but the video signal is kind of sketchy. It is not very strong, ...
Bart Friederichs's user avatar
19 votes
3 answers
2k views

Why was the VIC-II restricted to a hard-coded palette?

The MOS VIC in the VIC-20 and the MOS VIC-II in the C64 were capable of outputting 16 colours drawn from a hard-coded palette. It's clear that the palette size was fixed at 16 colours as a memory-...
Psychonaut's user avatar
  • 7,133
3 votes
0 answers
253 views

VisiCalc V1.0 is not working on modern computer as expected

I am trying to run Visicalc on the modern laptop (Lenovo Thinkpad X1 Extreme Gen.2). I created bootable flash drives with DOS 6.22 and Free DOS, booted from them and ran visicalc (vc.com file). All ...
Art Spasky's user avatar
16 votes
2 answers
2k views

What was the last terminal to include a physical bell?

Drew asks: … what was the latest terminal produced which rang a physical bell rather than beeping through a speaker?
scruss's user avatar
  • 21.6k
6 votes
1 answer
750 views

Maximum current a GBA Game Pak can continuously draw

The GBA (specifically model AGB-001) uses a boost converter to power the Game Pak with a stable 3.3V from its batteries. The SP and Micro models use a buck-boost regulator to generate that same 3.3V. ...
forest's user avatar
  • 2,029
2 votes
1 answer
202 views

Is it possible to view hardware-reported device identifiers on Windows ME?

On Windows XP and later you can view OS device identifiers for a given hardware component in Device Manager; those often include hardware-reported device identifiers, like PCI vendor/product ID pairs. ...
zomega's user avatar
  • 5,372
7 votes
1 answer
2k views

Is there something like Retr0bright but already made and trustworthy? [closed]

I have long wanted to clean up some old hardware to make it look new again. It really bothers me that it's all yellowed and depressing-looking. However, https://retr0bright.com/ wants me to purchase ...
Killgore's user avatar
3 votes
4 answers
2k views

What did game programmers and journalists mean by a "hardware trick"? [closed]

Recently, I've been hearing a good deal about hardware tricks. For instance, the YouTuber Ahoy (see A Brief History of Graphics) mentions that some game programmers resorted to "hardware tricks&...
AndrewGreen's user avatar
5 votes
1 answer
688 views

How did the Windows 95 'Add New Hardware Wizard' work?

I remember when Windows 95 came out and the 'Add New Hardware Wizard' seemed almost magical! It was able to detect a large amount of hardware on the COM ports and automatically install drivers. It was ...
simonhaines's user avatar
11 votes
5 answers
3k views

Why does MOS 6502 require an external clock if it has an internal oscillator?

I have a trouble understanding how the MOS 6502 clock works. Possibly due to my extremely low knowledge regarding electronics in general. According to the Wikipedia: MOS would introduce two ...
Andy's user avatar
  • 211
6 votes
4 answers
1k views

Fire button of Timex TC/TS 2068 Joystick

These pages wos and timex.comboios.info suggest the fire button of the Timex TC/TS 2068 joystick is read at bit 4. Input: bit D0: up (0=active) bit D1: down bit D2: left bit D3: ...
Rui F Ribeiro's user avatar
7 votes
2 answers
329 views

Was there ever a monospace display system (eg terminal) that used a vertical cursor?

Related to my earlier question about IBM PC cursors, I am now wondering if there has ever been a monospaced character display system (such as a terminal) that would've implemented a vertical cursor in ...
tuomas's user avatar
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