# Are these (dis)assembly screw symbols standardised?

Sometimes there are these two half-arrow symbols on PCBs and on enclosures. See the images, for examples.

Those symbols are often placed near the screws, that are to be unscrewed upon disassembly.

Are these symbols standardised? If yes, which standard they are from?

• Can't say i have seen them on all the items I have had apart - but they may well be standard somewhere. May 26, 2019 at 19:08
• I often see a triangle pointing to disassemby screws. May 26, 2019 at 19:13
• Sony discman, 1994 used this symbol on case screws. May 26, 2019 at 19:23
• On top of that @tomnexus said, all Japanese products I’ve taken apart have had these arrows to show which order at which a product is taken apart. May 26, 2019 at 20:19
• @SolarMike That's exactly what I thought, stumbling on this symbol once again :) May 27, 2019 at 15:11

After extensive* searching on the web with multiple search engines, I was (very surprisingly) unable to find any information about this symbol - which is honestly absurd, considering just how often I've encountered this symbol myself while disassembling PCs and other electronic equipment.

I was also unable to find it on any disassembly guide or PCB symbol chart.

This leads me to believe that this is some sort of informal standard used by PCB/equipment designers. It may very possibly be a regional thing too, since all my searches were in English.

Here's an incomplete list of stuff I've seen the symbol on, in case it helps someone with more experience identify it:

• A 2001 Yamaha Synth
• A 2012 HP All-in-one
• A 2007 Sony home theater
• A 1998 HP Brio tower
• Various HDD enclosures

*Most of my searches were combinations of the following terms (tried both with and without double quotes), on Google and DuckDuckGo: pcb, mounting, hole, screw, symbol, arrow, pointer, disassembly, pdf, schematic.

• Probably all Japanese designed boards Aug 2, 2019 at 16:23