This is rapidly becoming a FAQ here - how to convert between 110V and 220V mains. By far the easiest and safest way is to use a step-up transformer. It doesn't need to be an isolating transformer - an autotransformer is

You feed 110V in and get 220V out. Since 240V -> 110V transformers are fairly common in the UK, I would guess you can get the reverse in the

If you can't find a suitable transformer, then there's a sort-of kludge that works, but you need to take a little care when wiring it up. Get a mains transformer with _2_ 115V (or thereabouts) primary

Such transformers are fairly common, since by connecting the primaries

parallel you can use them in the States, and by connecting them is

(230V) you can use them in Europe. It doesn't matter what the

are, as you're not going to use them. Connect the windings in series, like you would for 230V mains. Connect the output across the 2 windings. Connect the 115V mains across one of them. In effect you're using the primaries as an autotransformer. The power rating of the transformer that you use should be about twice that of the computer you want to run. That gives a reasonable safety

Another way, which should be safe, but which for some odd reason is against the US electrical code is to connect the 220V unit to a 220V US outlet - the sort of thing you plug an air conditioner or whatever

It may be possible to modify the PSU. If it uses an iron-core 50Hz/60Hz transformer, then look to see if there are 2 primaries wired in series for 220V mains. Connect them in parallel for 110V mains - taking care

get the relative polarity correct. I'll not give any more details, because it really depends on the PSU design what you should do. For a switcher, the input circuit is often a bridge rectifier for 230V mains. If you can convert this to a voltage doubler, and if there's no line-frequency transformer for a start-up supply, then it should work. A lot of switchers have 2 smoothing capacitors in series - look for 2 large capacitors of about 470uF at 200V. Connecting the centre-tap of these to one side of the mains (after the switch/fuse/filter) will do

Often there's a link on the PCB (marked 'link for 115V' or something

that) for this purpose. Again, knowing how PSUs work is a great help

But I'd recomend the step-up transformer in your case. It avoids modification, and it's safe. How about a list of useful things for classic computer collectors, even for those who don't want to get involved with repair. I'd start with

following... Feel free to add things A transformer to convert your local mains into the 'other' standard.

a 110V step-down transformer for the UK, a 220V step-up transformer for the states. A composite monochrome monitor, capable of working with UK and US TV standards (almost all will do that). An analogue RGB colour monitor, TV scan rates A dumb terminal (or a PC + terminal emulator program) One of those RS232 quicktesters with red/green LEDs. (I use mine more than my Tektronix datacomms analyser) An assortment of cables. In particular IEC mains leads (like PC mains leads), RS232 cables (straight and null-modem), video cables (RCA -

BNC, PL259, etc) -tony