Roland MKS-50 Change Voltage

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Has anyone on the forum ever voltage switched the MKS-50?

I have the service manual and believe that I need to desolder / solder a wire but I cannot for the life of me work out which wire. If you look at the fuse board the middle pin on the right has the following options printed:

BLU 100v
GRN 117v
BRW 220v
RED 240v

Currently there is a Green wire solded to the pin. The transformer pins are not labelled, however there are two 'free' pins.

Does anyone know what I need to solder to make it 240v? there is no red wire, or 'red' printed anywhere other than the middle pin (that I can see).
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I have an MKS-50 but I've never had to change the voltage. I have two MKS-30s, one 110 and the other 220, I can tell you that the transformers have different part numbers. Take a look in the service manual, it's online. I'll look later if you can't find it.

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Yeah I have the service manual which does list different part numbers.

I guess what is confusing me is that the fuse board is printed with different voltages for the middle pin. I notice that even though the fuse board part numbers are different, the pcb number is the same.

Also, the fuse is 250v

Ah well, I'll give it 24 hours and if no one has done this before I'll just go out and buy a step down transformer.

Just out of interest, if there a site where we can find roland parts, such as this transformer?

Thanks for your help mate.

Cheers.

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mrfr0sty wrote:Yeah I have the service manual which does list different part numbers.

I guess what is confusing me is that the fuse board is printed with different voltages for the middle pin. I notice that even though the fuse board part numbers are different, the pcb number is the same.
I wouldn't really take anything from that.
Also, the fuse is 250v
Yep, common in the U.S., it doesn't mean anything. Fuse voltage rating is just about breakdown, as long as it's higher than the needed voltage, it's fine. They can use the same fuse everywhere.

There is some chance that the only difference is that the missing pin is wired, but it's risky to start playing with that unless you know what you're doing. IIRC, this can't be done on the MKS-30, but, don't quote me on it, I didn't try that hard.
Ah well, I'll give it 24 hours and if no one has done this before I'll just go out and buy a step down transformer.

Just out of interest, if there a site where we can find roland parts, such as this transformer?
You can try calling Roland, but I doubt that this is in stock any more. Really, the stepdown transformer is the way to go.
Thanks for your help mate.

Cheers.[/quote]

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Your current power is 110V I assume? And you want to modify it for 220/240 V?
Or vice versa, the principle is the same.

So assuming you have it connected to the current appropriate voltage, just put a multimeter set to measure "Voltage" to those pins. If you have it now connected to 110V and a certain pair of pins on the Mains side (left side on your photo) measures around 220V, then that's the pair you can use to modify it for the higher voltage. The reverse logic also applies.

Because after all it is just the transformer you're measuring. If the 110V connections are tapped off halfway the coil, the whole coil should have the double voltage. I think... ;-)

Chances are also these pins are in fact not connected at all. Hard to tell from that photo...
We are the KVR collective. Resistance is futile. You will be assimilated. Image
My MusicCalc is served over https!!

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BertKoor, thanks for your reply!

When you say try certain pairs, is there any combination that may short out the transformer?

I'm not that electrically savvy, but happy to have a go in the name of science :)

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mrfr0sty wrote:When you say try certain pairs, is there any combination that may short out the transformer?
Not as long as you have the multimeter set to measure Voltage, that should have a near-infinite resistance.

However if you have set it to measure Ampere, then it will short-circuit! Trust me on that, because that was the way I ruined an otherwise perfect functioning Arp Axxe. :-| :-o :cry:
We are the KVR collective. Resistance is futile. You will be assimilated. Image
My MusicCalc is served over https!!

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mrfr0sty wrote:BertKoor, thanks for your reply!

When you say try certain pairs, is there any combination that may short out the transformer?

I'm not that electrically savvy, but happy to have a go in the name of science :)
happy to fry...you and your mks50 ...in the name of science? take it to a tech, pay 50odd
quid and job done.

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