[sdiy] MKS-70 Switch internal transformer from US 117 to UK 240

[Richard Atkinson]

I just had a look inside my USA MKS-80. The power supply transformer has 
two taps, one for 100V (Japan voltage) and another for 117V (USA). It's 
clearly a 117V/100V device with no alternative wiring for 220V/240V. So 
there is no possibility of rewiring the USA MKS-80 transformer for 240V 
operation. It would have to be replaced with another transformer.

The MKS-70 service manual on the other hand seems to indicate that there 
are 100V, 117V, 220V and 240V taps on the MKS-70 transformer. (page 33 out 
of 44)

Apart from that, the mains input filters are different between 100/117V, 
220V and 240V, and there are different power connectors between 
100/117/220V and 240V.


On Sep 15 2010, random variate wrote:

>Thanks Richard
>
> Indeed it's C9, but I'd like to standardise as I use power distributers 
> with built in conditioners which are all c13/14, so I'd like to 
> standardise. I have C9s but the conditioners do clean things up a bit and 
> of course there's surge protection.
>
> I confess to being a newb with transformer tech so could you help a bit 
> further with regards to what to look for re: parallel/serial below.
>
>Once I'm happy with the mks job I'm going to rewire my US polysix too 
>
>Thanks all for replies, very much appreciated
>
>Tim
>
>
>
>On 15 Sep 2010, at 14:22, Richard Atkinson <rga24 at cantab.net> wrote:
>
>> If it's like the MKS-80 and the JX-10 I have here, the MKS-70 will use 
>> an IEC C9/C10 connector in both its US and UK incarnations. If you can 
>> find a UK C9 lead you should be able to use it with your MKS-70 once you 
>> have rewired the transformer.
>> 
>> Check the transformer very carefully when you do the rewiring job. Many 
>> multi-voltage transformers have two sets of primary coils, which are run 
>> in parallel for 110V and in series for 220V/240V.
>> 
>> 
>> On Sep 15 2010, random variate wrote:
>> 
>>> Hi there everyone, newb here
>>> 
>>> I'd like to get rid of my step up transformer wart on my US model 
>>> MKS-70 and have checked the internal transformer:
>>> 
>>> Currently soldered on 117v point and 0v point
>>> There are 220v and 240v winding points
>>> 
>>> The power filter board has a 250v rated glass fuse
>>> 
>>> 1. So, is the switch as simple as de/resoldering from the 117v point 
>>> to either the 220v point or 240v point
>>> 
>>> 2. Would anyone suggest using the 220 rather than 240v point?
>>> 
>>> 3. I'd also like to swap out the 2 pin US square power socket for a 
>>> Euro 3 pin IEC 'kettle' socket - there's no grounding though? Should I 
>>> just leave the grounding or would you suggest a chassis pin?
>>> 
>>> 
>>> Advance thanks
>>> 
>>> Tim
>>> 
>>> 
>>> 
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>
>