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

[Richard Atkinson]

I would certainly replace the 630mA fuse with a 315mA one.

Good luck with it, let me know how it goes.

Richard


On Sep 16 2010, random variate wrote:

>Thanks again Richard
>
> I have a few bits of kit that use the c9 power socket and have power 
> leads. I may update to the c13/14.
>
> The main issue for me is to ensure there are no component changes 
> required such as mains filter capacitors and the fuse.
>
>Was just concerned that you might have found out something I overlooked.
>
> Looks like I can just resolder the transformer and go... Which would be 
> ideal. Just need to double check the fuse issue though methinks.
>
>Cheers
>
>TC 
>
>
>
>
>
>On 16 Sep 2010, at 23:39, Richard Atkinson <rga24 at cantab.net> wrote:
>
>> The MKS-70 service manual shows different part numbers for the mains 
>> filter boards, and the fuse F1 has different ratings, but C1, C2, L1 and 
>> R1 are the same. Other than that the mains power connector is different, 
>> having a 3 pin socket for 240V. Have a look on page 33 out of 44.
>> 
>> Since the fuse for 220V/240V is actually smaller than for 100V/117V, it 
>> would still work with the larger fuse.
>> 
>> 
>> On Sep 16 2010, random variate wrote:
>> 
>>> Hi Richard, appreciate your looking in to this.
>>> 
>>> Am I right in taking your note to mean that I would need to change the 
>>> mains input filter board too?
>>> 
>>> I asked on Gearslutz and heard from one chap that the tech that worked 
>>> on his mks-70 just resoldered the transformer.
>>> 
>>> Thoughts?
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> On 16 Sep 2010, at 22:47, Richard Atkinson <rga24 at cantab.net> wrote:
>>> 
>>>> 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 
>>>>>>> _______________________________________________ Synth-diy mailing 
>>>>>>> list Synth-diy at dropmix.xs4all.nl 
>>>>>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>> 
>
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