PC Archeology: The plasma screen is probably the best

Part of the problem with using high density (1.44mb) disks as double density, as it's been explained to me, is that high density drives have a smaller read/write head, and even when you format the disk as double density, if you use a high density drive, it still writes to a smaller section of the disk. Some double density drives can read that fine, but others can't. If you plug a high density drive in to a computer that can only talk to double density drives, things work fine, as long as the disk is formatted for double density. It can read disks written as double density in a high density drive just fine, regardless of the type of disk. (since it is a high density drive) Also, if a high density disk was formatted and written as double density with a double density drive, things have also worked just fine, in my experience. The problems only seem to occur when you try to use a double density drive to read a high density disk formatted and written as double density on a high density drive.

Greetings Adrian!

Power supplies are my thing so, even if i am late to the comm section, i will say a few things about the subject.

There are a number of possible issues when a power supply receives only half of it's normal working voltage.
In fact there are too many to debate here, but to be short, if the supply even starts, and if it is a regulated supply ( most are, some are not ), then it will try to draw much more current from the input to maintain it's needed output/outputs under load, maybe more then double the current if you take into account increasing losses with increasing current.
This can cause some form of runaway and lead to magic smoke release.
That's because more current means more losses, and more losses means more power from the input for needed output, thus more power from input means more current, and more current means…
Also the power devices not being designed to work on this much current will probably fail anyway.

Still, coming back to "if they start", most PSU's will tend not to start, in short because of their UVLO protection.
Depending on how the control IC is powered there is a strong possibility that it's voltage would never get high enough to pass the UVLO threshold, thus the IC will not start the supply.
Also some IC's have line voltage monitoring, that can also prevent the supply from starting with only half of the voltage.

If those happy situations are not happening, then this is where stuff get's complicated, because if the control IC does receive enough voltage and signals on all it's inputs, then it will try to start the supply, and… and it get's even more complicated.
If the increasing current is high enough to trip the overcurrent protection, then the supply will either stop, or enter into a start/stop cycle with the soft start timing deciding the time between the states.
If neither of this situations are met, then there are other issues, because the IC will try to maintain the output as needed, and because the input is lower than normal, all the IC can do is increase the duty cycle ( or decrease the switching frequency in resonant PSU's ), but it can only go so far, so either the outputs will never go to where they need, and the supply will be very unstable and very noisy ( most likely to fail rapidly ), or it will reach it's needed outputs but will work with way higher losses ( both conduction and switching losses will be much higher ), that can also lead to magic smoke.

The happiest situation is when the supply is not regulated ( there are some in industry or home made cases ), here it can only go two ways:
1. The UVLO threshold will never be reached, so the unit will never start ( that is a happy situation, no magic smoke ).
2. The UVLO threshold somehow is reached thus the unit starts, and because there is enough working voltage for the IC, the power devices will be turned on with enough headroom as so the RDS-on ( Vce-sat ) is low enough.
The supply will work just fine, but, the outputs will only be about half of expected values, so if there is some form of regulation after the supply, and if there wasn't enough headroom designed in the supply, then the regulators will not be able to deliver the proper voltage on their outputs, and what is being powered by then will not work.

PS: There is much more to talk about this, but this is not a paper to publish, just a comment, so i'll stop here, hoping you did read it. So, never power a supply with half of it's working voltage.
All the best.

In the older 720K drivers – the width of the read-heads were problematic.

I type story's but I probally have vintage parts ya might be able to use I have several laptops apart bit I offer ot to those who love them I do love computers but see these were mine or parts machines anyway but I approve of today's level of storage and speed. But I did use a older one to make a atari and nes from gaming system so there plenty fast for that

These make awesome console arcade based systems just add a screen cabinet and walah

I don't use floppy today but I would if I could fit 1.44 on 1 see ya can just text documents games things like Paxkman Astroids ya know removable storage today I mean I could fit allot about history on a small SD card crazy talk scientists are smart

Or via cable maybe but it's thin so a new lcd or screen ya rgb to that interface and bypass the plasmas power spouce if ya wanted to have the retro look and sharper pixels on a working one I doubt thell last forever a 286 so

220V isn`t a weard voltage because a carbon arc lamp runs best on 55V, that`s also the reason for 110V in the US, weard is why the UK use 240V and why whole Europe converted to 230V and the UK still use 240V

Most SMPSUs you encounter will either be forward or flyback topologies. Forward converters (usually found on higher-output supplies) will usually have two primary-side transistors and each output will have a double-diode feeding an inductor. Flyback converters (common on lower-output supplies) only have a single primary switching transistor and each secondary has a single diode (or paralleled diode) directly feeding a capacitor without an inductor. Forward converters cannot produce full output voltage on reduced input voltage but flybacks (like this one appears to be) can. The main consideration is that the current in the primary coil and transistor will be higher and this could lead to overheating under full load. It might also have reduced output capability

TLDR: it will probably boot on 120v, at least without the extra load of hard drive. A quick test at 120v isn't going to hurt it but continued use might.

Plasma was better on those days for a display. I wasn't a gamer and I appreciated the text sharpness and contrast. Brightness was fine but not as good as a monitor. I didn't care when driving tens of thousands miles a year and could output code into productive solutions. For me, it was never the latest, greatest hardware . I just wanted to get things done. You're right though, a second floppy drive would be an ideal solution. I have a Toshiba T3100 but haven't booted it in years. I'm too old and tired to break it open.

@Adrian, diskchange is handled by small plastic rod on the left which is in the same spot as write protect.. i know this since i had a broken floppy drive on amiga 500 with broken diskchange plastic sensor.. so amiga didnt click and it was impossible to use without it… its actually a hardware problem not software

Hi Adrian, The floppy drive that came with the computer used 5 volt only it's spindle and head stepper are rated for a 5 volt operation that is probably that other berg connector was there someone used a 1.44 in there with it for a while.

230 vac most places here in Europe these days…

Hmm since you like plasma so much you should try getting the one for the Apple //c, and that one has a few colors too. Never saw one in person, but had classmate with one at home. Wonder if there are any surviving samples out there…