Questions tagged [power]

Questions and problems related to powering retro equipment.

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29 votes
5 answers
5k views

When/why did computers come to have push-button main power switches where on and off is the same push action?

In the top answer to Why were animated screensavers used instead of a black screen on CRT monitors? the main reason was said to be that it avoids users accidentally turning off the machine, thinking ...
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4 votes
2 answers
406 views

Why do computer rooms no longer have raised floors? [closed]

As I understand it, computer rooms in the days of mainframes and minicomputers, commonly had raised floors, so that the space under the floor could be used for power cables and cool air. I'm not clear ...
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8 votes
2 answers
2k views

Weird power lines for S-100, why no 5V?

In answering another question here on the S-100 bus (from my admittedly less-than-perfect recall), I wonder why the bus supplied 8 and 16 volt signals, relying on the boards to regulate this down as ...
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  • 2,386
28 votes
3 answers
21k views

Why do Game Boy Colors not want nickel-cadmium batteries?

This is a page from the manual for the Game Boy Color: There is no explanation as to why this is, or how this can be, but it claims that one must not use rechargeable nickel-cadmium batteries. Why is ...
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  • 281
1 vote
2 answers
476 views

Why did the description of the Windows shutdown command imply power-off was manual even with ACPI available?

The description of the ‘Shut down’ option in earlier versions of Windows reads: Ends your session and shuts down Windows so you can safely turn off power. Why was this shown in Windows 98–XP even ...
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29 votes
2 answers
4k views

What is the Commodore 64C "France version" and why does it need a beefy resistor?

While perusing the schematics for the Commodore 64C (titled COMMODORE-64 B/NE) I came across a suspicious section of the power supply: The unregulated "9V" is connected to the completely ...
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  • 1,689
11 votes
5 answers
4k views

Can a Japanese (or US) PSU for Nintendo 64 be run with 230 V mains?

The Nintendo 64 uses a proprietary PSU that takes mains voltage input and outputs 3.3 V and 12 V DC. PSU's from regions where mains voltage is 230 V (such as the EU) were sold as 230 V input while ...
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  • 315
3 votes
0 answers
173 views

PC AT power supply not providing correct voltage

I'm refurbishing a Pentium 120 PC with an AT power supply. It seems to work, at least nothing pops or smokes, but there's a slight problem with voltages, particularly on the motherboard connectors. ...
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5 votes
2 answers
387 views

Can I power a Windows 95-era AT PC with an ATX PSU, like this?

Is this the correct way to make the adapter? Will the "15A 120V AC ONLY" switch damage anything? The switch is illuminated. (glows when off)
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12 votes
2 answers
2k views

How did the Altair ensure that the −5 V supply was the first connected and last disconnected?

The Wikipedia page for the Intel 8080 processor describes pin 11 as The −5 V power supply. This must be the first power source connected and the last disconnected, otherwise the processor will be ...
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  • 13.8k
5 votes
1 answer
541 views

Could a BBC Micro power supply be replaced with USB power?

According to this video the BBC Micro's power supply provided a 5 Volt supply to the motherboard. Could a BBC Micro have it's internal power supply replaced with a USB power connector?
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  • 153
2 votes
2 answers
289 views

Which computer used the greatest number of DC supply voltages?

The original IBM PC supplied several voltages: +5 V, −5 V, +12 V, and −12 V. Which computer supplied the most DC voltages? To facilitate the comparison, let's agree on some uniform criteria for what ...
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  • 13.8k
2 votes
1 answer
199 views

Did the RTC in certain cartridges get power over the GBA bus?

Some GBA games, like Pokemon Ruby, contained an internal RTC with a small button battery to power it. When the cartridges were inserted and the GBA was powered on, did the RTC continue to run on the ...
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  • 1,771
4 votes
1 answer
189 views

Amstrad CPC 6128 - Bench Power Supply Connection Setup

I am definitely at the very beginning of my refurb-journey and learning every step now on the way ... I struggle with the following: I saw a video by Noel's Retrolab where he troubleshooted a CPC. He ...
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15 votes
7 answers
6k views

Why did the IBM PC have an internal power supply?

Microcomputers run off low voltage DC, but usually came with a power supply to produce a suitable DC current from the mains AC voltage. It was usual among early home computers to supply an external ...
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0 votes
1 answer
197 views

How picky are CRTs about power cleanliness?

How picky are CRTs about the 'cleanliness' of the mains power? Cleanliness referring to electrical noise from thing like ac motors in fridges, powerline ethernet, etc. Cleanliness is also referring ...
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10 votes
1 answer
1k views

Why did the C64 use a separate "CAN" +5 V power supply for some chips?

The Commodore 64 had two separate +5 V power supplies: one supplied by the external PSU brick and a second one generated on-board from the 9 VAC via a 7805 regulator. This second +5 V power supply was ...
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  • 20k
5 votes
2 answers
858 views

Two graphics cards for retro gaming

I'm considering installing two graphics cards in my retro gaming setup (one AGP and one PCI) and was wondering if there are any drawbacks to doing so? The main things I'm thinking about are power ...
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  • 391
1 vote
0 answers
65 views

Thinkpad 380E keeps shutting down randomly [closed]

Recently, I got a 380E from ebay. Seller says that it has boot error and not working, but the error was typical 161/163. I've replaced nee BIOS battery, and error was gone. After that, I formatted ...
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  • 163
3 votes
2 answers
357 views

Using generic SMPS adaptor on old IBM Thinkpad makes strange symptoms

I found abandoned IBM Thinkpad 560X inside of company's cabinet. So, I got curious and get generic AC-DC SMPS adapter for 10$. It was rated 16V 3.75A, diameter for plug is just right, and polarity was ...
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  • 163
2 votes
1 answer
1k views

How can I make an external PSU for an Apple IIc?

I purchased an Apple IIc from an auction site, but it came without the external power supply unit. While this question and its answers describe how to open up the IIc and use alligator clips to power ...
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  • 20k
22 votes
1 answer
2k views

How does the C64 get an accurate TOD clock on both 60 Hz and 50 Hz power?

The C64 has two Time of Day (TOD) clocks, one in each of its 6526 CIA chips U1 and U2. These calculate time based on a 60 Hz or 50 Hz input to the TOD pin (pin 19); the clock input frequency assumed ...
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  • 20k
9 votes
2 answers
602 views

What's the best way to hook up an external power supply to the Apple IIc without a 7-pin female DIN plug?

As seems to be typical with Apple IIc purchases these days, mine came without the external power supply. I have ordered some 7-pin female DIN plugs and other adapters that will let me plug a modern ...
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  • 20k
2 votes
2 answers
846 views

How much PSU power do I need for an AMD 386DX-40 computer?

Just picked up my first retro PC the other day. Unfortunately, it's lacking a PSU so I need to find one. What kind of a PSU (in terms of wattage) do I need to comfortably run an AMD 386DX-40 system? ...
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4 votes
1 answer
762 views

Discharging an AT power supply for maintenance

The power supply for one of my computers needs a new fan. How do I discharge the power-supply capacitors to make it safe to open up? With an ATX power supply, it's just a matter of unplugging it, ...
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  • 8,353
13 votes
4 answers
3k views

Do AT motherboards (286, 386, 486) really need -5V (besides redirecting it to ISA connectors)?

The power supply of my 386DX computer (an unknown brand M320 motherboard) is not trustworthy anymore, so I'm planning to use an ATX power supply, plus an ATX to AT adapter for P8-P9 connectors. The ...
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13 votes
5 answers
7k views

Does switching on an old games console without a cartridge damage it?

This is inspired by the question "What does a Nintendo Game Boy do when turned on without a game cartridge inserted?": Growing up in the 80s and 90s in the UK, it was "common knowledge" amongst my ...
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  • 241
7 votes
2 answers
964 views

Does the Commodore 64 power switch have a history of failing?

My original (1983?) Commodore 64 (brown breadbox with grey function keys) has trouble powering on. Specifically, when I flip the power switch the power LED will glow dimly and the machine fails to ...
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  • 8,416
7 votes
1 answer
370 views

How do you open an Amiga A590 Power supply?

I have an Amiga 590 hard drive, but the power supply appears to be dead on it so I want to take a look inside. I have removed three screws from the underside but it still won't open, acting like there'...
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  • 173
4 votes
2 answers
276 views

Sam Coupé power supply heat

I have a Sam Coupé and the last time I turn it on, i noticed a smell of components overheating. After opening the power supply I came to the conclusion that is the resistance R1 (50ºc with IR ...
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2 votes
1 answer
410 views

Commodore PC-1 power supply measurements off

I have a Commodore PC-1 with a busted power supply. I have no desire to fix it as I don't have the know-how it is already 30 years old It is difficult to debug / find replacement components So I ...
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  • 121
8 votes
2 answers
1k views

How to troubleshoot Amiga 600 power issue?

I have an A600 Rev 2D (schematic), which is dead as a doorknob. It was that way when I acquired it some years ago, and it's mostly been in storage since. Between the 5V rail and GND I measure a low ...
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5 votes
3 answers
634 views

What to check before powering on TRS80 Model III in unknown condition [duplicate]

Having managed to source a TRS-80 Model III that I'm told hasn't been powered on for quite some time (and I suspect this is a massive understatement), I'm worried that the first thing that might ...
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37 votes
6 answers
9k views

Why does the Cray 2 use 400 Hz power, and why generate that from motors?

This Cray sales brochure details on page 4 that the Cray-2 uses 400 Hz power, and generates this from motors. 400 Hz power from motor generators I'm not sure that in 1986, the state of the art ...
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3 votes
1 answer
401 views

Transatlantic gray market Commodore PETs and 220V/50Hz vs. 115/60Hz

In the late seventies, Commodore sold the PET in Europe at a considerably higher price than in America; they could get away with this because there was less competition there. Some of the American ...
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  • 48.8k
4 votes
4 answers
327 views

Running European retrocomputers on 60Hz power?

I have 3 European retro computers that I'm trying to run on North American power through a step-up transformer. So, I am using 220V/60Hz instead of the European standard of 220V/50Hz. BBC Master ...
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  • 56.5k
10 votes
4 answers
1k views

Why the switch to "Mickey Mouse" (type C14) power cables?

Inspired by this question asking about "regular" power cables, I have been curious about (read: irritated by) the rise of "Mickey Mouse" power cables. Apparently they come from the same standards ...
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  • 855
28 votes
7 answers
12k views

Why did computers use a power supply with a socket?

Most home electrical appliances use a fixed power cord and have a on/off switch near the front. I was in many government electronics labs and that cord and socket was not used i.e HP test equipment. ...
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  • 4,281
4 votes
0 answers
312 views

Cost of Apple II switching power supply

Apple went to the trouble of designing a switching power supply at a time when they were still quite new and not widely used for consumer electronics, perhaps because Steve Jobs liked the aesthetics ...
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  • 48.8k
110 votes
23 answers
38k views

Was there ever any reason to wait 30 seconds to restart a c.1995 PC?

I owned a PC in the mid-to-late 90s, and while everyone said when you turn it off and back on again, count to 30. But it also had an instant reset button down below. Was there ever really any risk ...
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  • 1,141
2 votes
2 answers
713 views

Was there ever a kilowatt workstation?

Back in the day, workstations used to get impressively big. Take a look at this — sure, a modern laptop has more computing power, but you don't see personal computers weighing eighty pounds these days....
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  • 48.8k
5 votes
2 answers
481 views

Checklist for powering up an Apple IIgs?

I've just been given an Apple IIgs that hasn't been turned on since 1999. What's a reasonable set of checks to go through to make sure I don't toast the thing the first time I plug it in? The machine ...
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  • 17.1k
54 votes
2 answers
11k views

Why did Commodore fill their power supplies with epoxy?

If you know anything about the Commodore 64 (and other Commodores, really) you know that Commodore really went the cheap route and produced some awful power supplies. The Commodore 128 PSU isn't ...
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  • 7,981
7 votes
2 answers
2k views

Macintosh LC II power supply clicking

I have a Macintosh LC II that I just acquired. When I attempted to power it on, I got nothing. No tones, no LED, no fan...nothing. I took out the power supply and tried to measure any voltage ...
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  • 7,981
2 votes
1 answer
411 views

When did computers start being able to take both 115 and 230 volts? [closed]

With modern computers and game consoles, it's common to have the ability to take 115 or 230 volt mains supply, selected by a small switch on the back of the machine. Presumably the logistical ...
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  • 48.8k
8 votes
2 answers
1k views

Can a standard ATX power supply be used on a Macintosh Performa 476?

I just received a Performa 476 and was shocked at the amount of rust in the computer. I believe it literally sat underwater for some time. The motherboard looks like it can be salvaged but the power ...
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  • 7,981
14 votes
4 answers
2k views

Original Mac capacitor inspection

Which capacitors should be inspected and, if necessary, replaced before attempting to power up an original Mac (purchased January 1984, but "upgraded" to a 512Ke) that has been sitting unused for a ...
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  • 7,454
13 votes
5 answers
643 views

When did energy saving start to become important?

There was a time where computers often just stayed on all the time. Computer monitors did not have power save functions... they were either on or off. Processors such as the 6502, 68000, 8086, 286, ...
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  • 3,341
12 votes
1 answer
1k views

What is the proper way to test the PSU output for a Commodore 128D?

This question is directly related to comments on the more general question and answer here. The Commodore 128D and 128D-CR have an internal PSU that can be readily and safely disconnected from the ...
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  • 56.5k
7 votes
2 answers
725 views

Can I power a z180 with 3.3v [closed]

I'm planning to buy a Z8018006PSC. A z180 CPU (which I found is compatible with the z80 and has some advantages, for instance, able to address up to 1MB of RAM). I'm planning to use it together with ...
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  • 155