Questions tagged [power]
Questions and problems related to powering retro equipment.
69
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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 ...
- 223k
1
vote
0
answers
209
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ATX mainboard always on
I am moving my 6x86 system into an ATX case from an AT case. The mainboard is Amptron PM9800 supporting both AT and ATX power supply.
As soon as I apply power on the power supply, the system turns on ...
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6
votes
1
answer
752
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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. ...
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3
votes
1
answer
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Questions about IBM PC PSU P8 key pin and change to +5V for AT
According to the IBM PC/XT Technical Reference page 3-6, pin 2
of plug P8 is a "key." (Note that this is the pin specifically; this is
separate from the keying of the shroud, which is ...
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1
vote
1
answer
223
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Commodore 64c supply 9 Vac waveform specs
I found an old Commodore 64c without a box, cable, or anything else and I want to put it back to work.
In order to do so, I need to turn it on to see if it works. I've already found the pinout of the ...
- 3,754
4
votes
1
answer
127
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What is the power adapter voltage and polarity for an Avatex 1200 modem?
My very first modem was an Avatex 1200 connected to my trusty C64. Unfortunately, the power adapter has long since been, let's say, disassociated from the hardware. I probably still have it, but the ...
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5
votes
1
answer
201
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Correct voltages and current draw for Commodore PC-1
I am fixing a Commodore PC-1 PSU for a friend and want to know if the PSU is behaving as expected. No modern PSU suggestions (e.g. Meanwell), if you don't mind! :)
Question: What are the voltage ...
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5
votes
2
answers
725
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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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20
votes
5
answers
8k
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The Cray 1 used 115 kW of power. How was that much grid power physically delivered to the unit?
We are talking power plant levels of current to power the the thing. Did it just have 2 inch lugs?
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2
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0
answers
135
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Atari 1040 STFM power supply issue & high-pitch noise
I have an Atari 1040 STFM that's been sitting in the basement for about 30 years. It doesn't power on. The power indicator light is not illuminated and there's a high-pitch noise coming from the power ...
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0
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1
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152
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What if ATX 12v P4 power connector was introduced 4 years earlier? [closed]
AT power supply handled +5 and +12 volts, +5 for ISA and processors, +12 for motors in disk drives.
In 1995 486DX2 was introduced with 3.3V core, so it derived that from a simple but inefficient ...
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147
votes
5
answers
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It's now safe to turn off your computer
One thing I remember very well from my childhood is the screen you got at the end of a shutdown process on old computers:
I don't know if this was a Windows 95/98/2000/ME only thing but I wonder why ...
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4
votes
1
answer
3k
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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 ...
- 26k
1
vote
0
answers
184
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Monochrome CRT, words are wavy and sometimes move forward and backward, what could be the issue?
Monochrome CRT characters are not stable and rather shaking or waviness in them, sometime feel like moving forward and backward. Issue is in the high voltage power supply but what could it be, do high ...
9
votes
1
answer
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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 ...
- 23.1k
58
votes
2
answers
12k
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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 ...
24
votes
2
answers
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How and why did the ZX Spectrum use so many voltages?
Whilst researching the Zilog Z80, I had found that it accepts a 5V power supply.[2] When looking for information on the ZX Spectrum, I found that its power adaptor produces 9V.[1] Confused, I did some ...
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29
votes
5
answers
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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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votes
2
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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 ...
- 223k
4
votes
2
answers
624
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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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113
votes
23
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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 ...
29
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3
answers
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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 ...
- 32.1k
1
vote
2
answers
632
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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 ...
- 23.1k
31
votes
2
answers
4k
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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 ...
- 38.9k
5
votes
1
answer
863
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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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votes
5
answers
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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 ...
3
votes
0
answers
197
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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. ...
- 23.1k
5
votes
2
answers
502
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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
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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 ...
- 23.1k
2
votes
2
answers
327
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 ...
3
votes
1
answer
301
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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 ...
- 10.1k
8
votes
2
answers
1k
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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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4
votes
1
answer
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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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votes
7
answers
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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 ...
- 21.6k
0
votes
1
answer
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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 ...
- 153
10
votes
1
answer
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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
...
- 10.1k
5
votes
2
answers
1k
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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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1
vote
0
answers
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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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12
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1
answer
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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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3
votes
2
answers
363
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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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4
votes
2
answers
312
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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 ...
- 10.4k
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 ...
- 223k
2
votes
2
answers
1k
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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
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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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13
votes
4
answers
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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
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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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8
votes
2
answers
1k
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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 ...
- 327
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1
answer
518
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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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23
votes
5
answers
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How can I power a C64?
I was chatting with our neighbor and after some long talking, I found out that he has a Commodore 64. I'd love to test it, however I'm not sure how to power it.
How can I power a C64?
5
votes
3
answers
691
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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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