Why was Sinclair selling UK model ZX81s in the USA?
Posted: Thu May 17, 2018 10:46 pm
Hello all. I've been active on other vintage computer forums but this is my first post here because I have a very specific question and this looks like the best place to ask it.
When you look on U.S. eBay there's usually about a 50/50 mix of U.S. and UK Sinclair ZX81s for sale (from North American sellers). Maybe some of the UK models were personally brought over by British expats, but that can't possibly be the case for all of them, especially since many of the UK models are bundled together with a U.S. power supply, U.S. RAM expansion module ("ZX81 USA" printed on the back), and U.S. literature. That was the case with my ZX81 that I got on eBay a few years ago -- the computer itself is a UK model but everything else is from the USA, as shown in this video.
Just a little clarification: in addition to being rebranded and sold by Timex in the USA as the Timex-Sinclair 1000, the ZX81 was also sold via mail order from Sinclair Research in Nashua, NH. The U.S. model is distinguished from the UK model by having a channel 2/3 switch underneath for its RF modulator, whose output jack is towards the rear of the case, while the UK model's RF output is closer to the other jacks. The U.S. model also has the New Line button marked as Enter and the Rubout button marked as Delete. And on the bottom it has "ZX81 USA" printed on it, with an FCC ID.
Now here's the smoking gun: a UK model ZX81, in the original box, with the original shipping label, showing it being shipped from Sinclair Research in New Hampshire to a U.S. customer:
https://www.ebay.com/itm/112994034031
So the question is, does anybody know why Sinclair was selling UK ZX81s in the USA? The closest thing I've come up with is a letter I saw of Sinclair explaining to a U.S. customer who had bought a ZX81 kit that they had run out of kits and had instead shipped them a fully assembled machine at no extra charge. So is it also possible that during this time of peak demand for ZX81s, Sinclair was also selling UK models to U.S. customers as a substitution?
Back in the day of manually tuned TVs, it was no big deal to use a UK ZX81 with a U.S. TV set, because the UK channel 36 (which virtually all British computers use) matches up with U.S. UHF channel 34, and with an adjustment of the V-Hold knob, you can get an old TV to sync up to the 50 Hz refresh rate instead of the 60 Hz used by U.S. TV signals. (In this case the difference in color subcarrier frequency between PAL and NTSC is irrelevant because the ZX81 is of course black & white.)
So that's my theory of what was going on -- but I'd love to hear from anyone who either has proof of it, or an alternate explanation. Did anyone here in the USA or Canada order a ZX81 from Sinclair Research back in the day and get a UK model? Or know anyone else who did?
When you look on U.S. eBay there's usually about a 50/50 mix of U.S. and UK Sinclair ZX81s for sale (from North American sellers). Maybe some of the UK models were personally brought over by British expats, but that can't possibly be the case for all of them, especially since many of the UK models are bundled together with a U.S. power supply, U.S. RAM expansion module ("ZX81 USA" printed on the back), and U.S. literature. That was the case with my ZX81 that I got on eBay a few years ago -- the computer itself is a UK model but everything else is from the USA, as shown in this video.
Just a little clarification: in addition to being rebranded and sold by Timex in the USA as the Timex-Sinclair 1000, the ZX81 was also sold via mail order from Sinclair Research in Nashua, NH. The U.S. model is distinguished from the UK model by having a channel 2/3 switch underneath for its RF modulator, whose output jack is towards the rear of the case, while the UK model's RF output is closer to the other jacks. The U.S. model also has the New Line button marked as Enter and the Rubout button marked as Delete. And on the bottom it has "ZX81 USA" printed on it, with an FCC ID.
Now here's the smoking gun: a UK model ZX81, in the original box, with the original shipping label, showing it being shipped from Sinclair Research in New Hampshire to a U.S. customer:
https://www.ebay.com/itm/112994034031
So the question is, does anybody know why Sinclair was selling UK ZX81s in the USA? The closest thing I've come up with is a letter I saw of Sinclair explaining to a U.S. customer who had bought a ZX81 kit that they had run out of kits and had instead shipped them a fully assembled machine at no extra charge. So is it also possible that during this time of peak demand for ZX81s, Sinclair was also selling UK models to U.S. customers as a substitution?
Back in the day of manually tuned TVs, it was no big deal to use a UK ZX81 with a U.S. TV set, because the UK channel 36 (which virtually all British computers use) matches up with U.S. UHF channel 34, and with an adjustment of the V-Hold knob, you can get an old TV to sync up to the 50 Hz refresh rate instead of the 60 Hz used by U.S. TV signals. (In this case the difference in color subcarrier frequency between PAL and NTSC is irrelevant because the ZX81 is of course black & white.)
So that's my theory of what was going on -- but I'd love to hear from anyone who either has proof of it, or an alternate explanation. Did anyone here in the USA or Canada order a ZX81 from Sinclair Research back in the day and get a UK model? Or know anyone else who did?