Reddit reviews Master Electrician 6-Feet Indoor Extension Cord with 3 Outlets and On/Off Switch , Black

They make in-line ac power switches. You can either install them yourself or using something like this:

https://www.amazon.com/Master-Electrician-6-Feet-Extension-Outlets/dp/B000W65LO2/ref=sr_1_fkmr1_1?keywords=inline+ac+power+switch+iec320&qid=1573683036&sr=8-1-fkmr1

There are power supplies you can get that come with a power button on the cord. I have personally had bad luck with those, resulting in low voltage warnings despite having a properly sized power supply. If you put a switch before the power supply you don’t have to worry about any of that.

Here are a couple of options that would accomplish this:

GE Grounded On/Off Power Switch, Plug-In, White, Energy Efficient, Space Saving Design, UL Listed, 15A, 120VAC, 1800W, 25511 https://www.amazon.com/dp/B0113VTPSW/ref=cm_sw_r_cp_api_USbaCb1YJNQ9Z

Master Electrician 6-Feet Indoor Extension Cord with 3 Outlets and On/Off Switch , Black https://www.amazon.com/dp/B000W65LO2/ref=cm_sw_r_cp_api_7VbaCb9Q114BB

I’ve see people use this...

https://www.diyretroarcade.com/index.php/power/outlet.html

This is what I ordered...

https://www.amazon.com/Master-Electrician-6-Feet-Extension-Outlets-x/dp/B000W65LO2

Perhaps you're looking for a cable with an "in-line switch". If you DIY one, be sure to switch the hot, not the neutral, and only use a polarized plug (one prong larger than the other).

I used to use the same method (with a wrist watch, pre smart phone days). It works pretty well if your times aren't long. Consider getting an extension cord with in-line switch to make it easier.

After getting sick and tired of looking at my watch, I started using these photo enlarger timers which is what I've been using ever since. Well, I have a digital one now but essentially the same thing.

As far as the vacuum, I've not needed one for my stuff but I don't do a lot of fine halftones or complicated index prints. If you DO want to do process or index prints, you will probably need the vacuum.

A bit late on this, but this was happening to my new (30 year old) JVC AL-F3. It just righted itself out of the blue the other day, so it's fine now. Still, if you haven't found a solution, I'd recommend buying an extension cord with an on/off switch, like this one:
https://www.amazon.com/gp/product/B000W65LO2/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
The switch on that is closer to where you plug in everything else, so what I did was just put the switch in the nook between my turntable and the side of my shelf.

How about a small power strip or a switched extension cord with multiple outlets.

Could be a problem with the mainboard or power supply. Neither of those things are cheap or quick fixes, and for a problem as simple as "I need to turn it on via the power switch at the back", I'd live with it. If it's absolutely unbearable, like you've gotta crawl under the desk every time you want to turn the computer on, then I suggest getting an extension cord with a switch in the middle, so that you can have that switch you need in a convenient location.