Back until the late 80ies, it was actually pretty commonplace to get a circuit diagram with a lot of electronics devices when you bought them - Even TVs and radio sets often came with them.
In cases where the device didn't come with a schematics directly, you were at least able to request one from the manufacturer in most cases. Sinclair, for example, did ...
To clarify Tim Locke's comment about the Commodore 64 Programmer's Reference having a schematic, here are a couple of quick photos of the copy I lucked into in 2003.
The rest of the book includes things like pinouts for the ports, data sheets, block diagrams and timing diagrams for chips like the 6510 CPU and the 6581 SID, complete references for the ...
I remember the computers from Czechoslovakia back in the 80s', and they come with the circuit diagram automatically, especially those for "professional use". The manufacturers knew that users have to repair those computers or build their own peripherals.
Other computers, e.g. the "hobby computer" PMD-85, come with the block diagram and ...
At my university in the 70's
was an Adage Graphics Terminal,
a full-blown digital computer
(30-bit, one's complement!)
along with analog graphics hardware
driving a 3D vector display.
It was the size of about
3 refrigerators, full of discrete components,
had a very loud hard disk
(itself the size of a large desk)
with removable packs,
a tape drive,
Schematics for the Sun2 came with the workstation, and for the Sun3 were available upon request.
I received the schematics for the BBC Micro as part of their Service Manual. This had a somewhat restricted distribution, but samizdat photocopies were easily found.
These days service manuals don't include full schematics, as manufacturers won't warrant field ...
In early 1980, Harvey Mudd College got one of the first VAX-11/780s, one of the first 32-bit mini-computers. It included complete schematics for everything. HMC was (and is) a STEM school. It was an educational experience - we could see how DEC tied together a bunch of 74000 series bit slices to create an ALU, we could see how the microcode out of its ...
I'm afraid that I have to disagree with @Raffzahn, in part citing @JeffSilverman's answer relating to DEC equipment.
Focussing on mainframes, and in particular Burroughs Large Systems (capitalised since that was what the range of ALGOL-based systems were called), I cite this reference https://users.monash.edu.au/~ralphk/burroughs.html which comprises the ...
Modcomp minicomputers, popular for communications processing and process control, came with full schematics as well as manuals describing how the hardware operates. Everything came in thick three-ring binders; I think the schematics were fold-out.
I know this is true for the Modcomp II, which was wire wrapped. I think (my memory is hazy) it was also true ...
The questions wording (discrete, valve) makes it sound as if it's about early systems, not microcomputer and maybe not even mini-computers.
Here it may be safe to distinguish one off machines (which covers moste valve based) and in numbers produced units. One-offs were usually also full or in part developed by their users, so circuit diagrams were of course ...
The Memotech MTX computer (circa 1983, 4MHz Z80A, 24 KB ROM, 32 or 64 KB RAM, 9918A/9929A VDP, 16KB VRAM) came with a manual with full circuit diagrams at the back, and even selected extracts from chip specifications (eg: VDP).
The Apple II Reference Manual that came in the box included a complete schematic. One did not need to purchase any additional (programmers reference or service) manuals.
The Apple III manual did not include a schematic. One needed to purchase a service manual to get an official copy.
The RCA B&W vacuum tube TV my parents purchased circa 1960 had a full ...