61
Strange chip: Teardown of a vintage IBM token ring controller
IBM used some unusual techniques in its integrated circuits, and one of the most visible is packaging them in square metal cans. I've been...
Ken Shirriff
Computer history, restoring vintage computers, IC reverse engineering, and whatever
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Visit righto.com → RSS feedOn Hacker News Jul 2013 – Oct 2026
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62
How flip-flops are implemented in the Intel 8086 processor
A key concept for a processor is the management of "state", information that persists over time. Much of a computer is built from logic gate...
63
Silicon die teardown: a look inside an early 555 timer chip
If you've played around with electronic circuits, you probably know the 555 timer integrated circuit, 1 said to be the world's best-selli...
64
Inside a 20-Watt Traveling Wave Tube Amplifier from Apollo
How did the Apollo astronauts communicate on their trip to the Moon, 240,000 miles back to Earth? They used a 32-pound amplifier, built ar...
65
Repairing a 1960s mainframe: Fixing the IBM 1401's core memory and power supply
A few weeks ago, I wanted to use one of the vintage IBM 1401 mainframe computers at the Computer History Museum, but the computer wasn't wor...
66
A one-bit processor explained: reverse-engineering the vintage MC14500B
The Motorola MC14500B 1 is a 1-bit processor introduced in 1976. While a 1-bit processor might seem almost useless, 2 it was marketed as...
67
Reverse-engineering the conditional jump circuitry in the 8086 processor
Intel introduced the 8086 microprocessor in 1978 and it had a huge influence on computing. I'm reverse-engineering the 8086 by examining t...
68
How the Z80's registers are implemented
The 8-bit Z80 microprocessor is famed for use in many early personal computers such the Osborne 1, TRS-80, and Sinclair ZX Spectrum. The Z80...
69
Yamaha DX7 reverse-engineering, part III: Inside the log-sine ROM
The Yamaha DX7 digital synthesizer (1983) was the classic synthesizer for 1980s pop music. It used two custom digital chips to generate so...
70
Repairing the card reader for a 1960s mainframe: cams, relays and a clutch
I recently helped repair the card reader for the Computer History Museum's vintage IBM 1401 mainframe. In the process, I learned a lot abou...
71
An 8-tube module from a 1954 IBM 705 mainframe: it's a key debouncer
IBM's vacuum tube computers of the 1950s were built from pluggable modules, each holding eight tubes and the associated components. I recent...
72
Reverse-engineering a vintage power supply chip from die photos
I recently did a PC power supply teardown so I figured it would be interesting to go deeper and see what happens inside the power supply'...
73
Why the Z-80's data pins are scrambled
If you look closely at the datasheet for a Z-80 chip, you'll notice the data pins are in a random-looking order. The address pins (A) are ni...
74
Teardown of a quartz crystal oscillator and the tiny IC inside
The quartz oscillator is an important electronic circuit, providing highly-accurate timing signals at a low cost. A quartz crystal has the...
75
A look inside the chips that powered the landmark Polaroid SX-70 instant camera
The revolutionary Polaroid SX-70 1 camera (1972) was a marvel of engineering: the world's first instant SLR camera. This iconic camera wa...
76
Tracing the roots of the 8086 instruction set to the Datapoint 2200 minicomputer
The Intel 8086 processor started the x86 architecture that is still extensively used today. The 8086 has some quirky characteristics: it i...
77
Reverse engineering the 76477 “Space Invaders” sound chip from die photos (2017)
Remember the old video game Space Invaders? Some of its sound effects were provided by a chip called the 76477 Complex Sound Generation ch...
78
Inside the HP Nanoprocessor
The Nanoprocessor is a mostly-forgotten processor developed by Hewlett-Packard in 1974 1 as a microcontroller 2 for their products. Stra...
79
Examining circuit boards from the Space Shuttle's I/O Processor
The Space Shuttle's five 1 general-purpose computers played a critical role in each flight: controlling the engines, monitoring thousands o...
80
Cores in space: The core memory module from a 1980 Spacelab computer
Spacelab was a reusable laboratory that could be carried in the Space Shuttle's cargo bay, providing lab space for astronauts and experiment...
81
Inside an IBM/Motorola mainframe controller chip from 1981
In this article, I look inside a chip in the IBM 3274 Control Unit. 1 But before I discuss the chip, I need to give some background on main...
82
Glowing mercury thyratrons: inside a 1940s Teletype switching power supply
We recently started restoring a Teletype Model 19, a Navy communication system introduced in the 1940s. 14 This Teletype was powered by a b...
83
The digital ranging system that measured the distance to the Apollo spacecraft
During the Apollo missions to the Moon, a critical task for NASA was determining the spacecraft's position. To accomplish this, they devel...
84
The printer that wouldn't print: Fixing an IBM 1401 mainframe from the 1960s
The Computer History Museum has two operational IBM 1401 computers used for demos , but a few weeks ago one computer suddenly couldn't prin...
85
Inside the 8086 processor, tiny charge pumps create a negative voltage
Introduced in 1978, the revolutionary Intel 8086 microprocessor led to the x86 processors used in most desktop and server computing today....
86
Restoring Y Combinator's Xerox Alto, day 3: Inside the disk drive
I'm helping restore a Xerox Alto — a legendary minicomputer from 1973 that helped set the direction for personal computing. This post desc...
87
Reverse-engineering the first FPGA chip, the XC2064
A Field-Programmable Gate Array (FPGA) can implement arbitrary digital logic, anything from a microprocessor to a video generator or crypt...
88
Inside the 8086 processor's instruction prefetch circuitry
The groundbreaking 8086 microprocessor was introduced by Intel in 1978 and led to the x86 architecture that still dominates desktop and se...
89
Reverse-engineering the division microcode in the Intel 8086 processor
While programmers today take division for granted, most microprocessors in the 1970s could only add and subtract — division required a sl...
90
A computer built from NOR gates: inside the Apollo Guidance Computer
We recently restored an Apollo Guidance Computer 1 , the computer that provided guidance, navigation, and control onboard the Apollo flight...