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In the late seventies, Commodore sold the PET in Europe at a considerably higher price than in America; they could get away with this because there was less competition there. Some of the American dealers took advantage of this by surreptitiously shipping PETs across the Atlantic, much to Commodore's annoyance.

Technically, how did this work? The PET power supply was built into the case; it had a single power cable that expected ~115 volt (?) 60 Hz, not 220-240 volt 50 Hz. Even if you took out the power supply and replaced it with one suitable for Europe (was it an off-the-shelf item?), the 2001's monitor was a picture tube from a black-and-white TV set, which would presumably have been expecting 60 Hz power. How could an American PET work in Europe?

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In the late seventies, Commodore sold the PET in Europe at a considerably higher price than in America; they could get away with this because there was less competition there.

Let's say market structure was different.

Some of the American dealers took advantage of this by surreptitiously shipping PETs across the Atlantic,

Jup, and as well as many customers tried to buy direct. Here payment was the biggest hurdle, but there was a way to pay via the post office - but that's a different story. Well, and haggle with customs - but that's another :))

Technically, how did this work? The PET power supply was built into the case; it had a single power cable that expected ~115 volt (?) 60 Hz, not 220-240 volt 50 Hz.

First and most simple solution was using a transformer (like this). Not cheap, but still saving money - and usually cheaper than a new PS - at least when only converting a few units.

Even if you took out the power supply and replaced it with one suitable for Europe (was it an off-the-shelf item?),

Such 1:2 transformers are stock items, so no need to worry about the PS. The lower frequency doesn't matter as the result is way within tolerances.

the 2001's monitor was a picture tube from a black-and-white TV set, which would presumably have been expecting 60 Hz power.

Why? It derives its timing from the video signal the PET supplies, which in turn is taken from the oscilators, not in any way taken from or synchronized by mains. The video signal is still the same with 50 Hz power, thus no adjustment needed.

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    Follow-up question, electronics dunce as ever: does the screen actually receive AC power? If so, would a new power supply actually do the trick? The possible cause of confusion, if my question is stupid: don't computer PSUs convert AC to DC, so wouldn't it be downstream or parallel to the monitor feed? I'm curious as to whether you'd end up with the transformer somewhere in the mix no matter what you did. – Tommy Aug 29 '18 at 3:22
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    @Tommy Well, he receives AC, but not mains. 15V (21V for 12" screen) are fed into the video board from the transformer and right away rectified and turned into 12V DC, which then are used to handle everything within. -- The 1:2 Transformer mentioned is to be connected prior to the computers inlet. -- And no, what a PSU does depends on the comuter, but there is no need for the CRT to receive AC, and especially not mains. – Raffzahn Aug 29 '18 at 10:20
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    @Tommy See [here] (zimmers.net/anonftp/pub/cbm/schematics/computers/pet/2001/…) for the PET video board - 15V AC is fed into connection 1/2. And see here for a description of the transformer. This is for an 8032, but it's the same for all PET. – Raffzahn Aug 29 '18 at 10:24
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    Any city vaguely near a military base with US troops (so, any reasonably-sized city in western Europe) had an electronics store with transformers designed to run US equipment on 240V. In the early 1990's in Amsterdam I found a pile at an electronics store (all kinds of random parts). (Although I bought it as I was moving back to the US so I could rewire it to run 240V equipment on 120V). – Jon Custer Aug 29 '18 at 13:11
  • 240V would be UK, wouldn't it? :)) – Raffzahn Aug 29 '18 at 13:13

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