Valve's own Steam Machine repair guides are live on iFixit, but no parts are for sale
iFixit has published 17 Steam Machine repair guides written from Valve's own instructions, and it sells no spare parts for the console. The list runs from an 11-step SSD swap to a 55-step motherboard job, with the heatsink and the internal power supply the longest at 57 steps each.

Steam Frame has an iFixit device page, but no repair guides on it. Image: Valve
The guides went up on September 16, three months after the Steam Machine shipped in June. Valve's console starts at $1,049 in the US, so owners have a real interest in how far into it they can get with a screwdriver.
The longest jobs run to 57 steps
Sixteen of the guides cover replacing a part, and one is a technique walkthrough for opening and cleaning the machine that runs to 38 steps of its own. RAM replacement takes 49 steps against 11 for the SSD: the drive comes out near the start of the disassembly, while reaching the memory means working through most of the machine first.
Valve's RAM procedure says the console takes two DDR5-5600 SODIMM modules, and the SSD walkthrough covers moving the mounting point when the new drive is a different length.
The rest of the list covers the back panel, faceplate, fan, feet, front port cover, the front USB and power button board, the HDMI and DisplayPort board, the rear USB and Ethernet port board, the SSD board, the shell and the microSD card reader. An eighteenth guide, for assembling the Inkterface, has been up since August 5.
There is no repairability score for the Steam Machine. iFixit has not published one, so the step counts are the closest thing to a difficulty rating an owner has.
Valve's own files are linked from the guides
Each of the 17 carries an OEM label saying that iFixit collaborated with the manufacturer to make the guide. The device page also points to Valve's own Steam Machine repository on gitlab.steamos.cloud and to the Inkterface files kept there. Neither company has announced the work, so the label and the links are what establish it.
No spare parts are on sale
iFixit lists tools only for this device, among them a spudger, a Phillips #1 screwdriver and a games console cleaning kit. Anyone who follows the 55 steps to lift out a motherboard has to find the replacement board somewhere else.
Steam Frame owners get nothing comparable yet. iFixit's Steam Frame device page is live but holds no guides, which leaves the headset where the Steam Machine sat through the summer. The console, for its part, still cannot stream VR games to a Steam Frame.
For now the paperwork is ahead of the supply chain. You can read exactly how to replace a Steam Machine motherboard, and buy every tool the job needs, except the motherboard.