InTheStudy wrote on 2024-03-19, 22:44:

do NOT get me started on Brexit, for the love of god.

and that's not all, on top of it - Parcelforce are not accepting Bank cards not issued by UK bank for online payment of duties:

https://www.reddit.com/r/royalmail/comments/q … _when_i_try_to/

it's really insane and even the above post is 2 years old, I can confirm it's still in place - had that problem few weeks ago. Not to mention that I was trying to use card from UK bank, but just issued from a branch that is overseas, which is double insane!!

Getting back to the original question; Stepdown converters in the UK...

I use these three:

This one powers a Sharp X68000 Super.

This one runs a Sony MSx2+, HB-FX1DJ.

And that last one I had running an NEC PC-9821An.

I suspect for your purposes you don't need anything as big as the first and last. I can't vouch for the long term reliability of any of them, as you can probably imagine those particular machines don't get as much as use some other, UK mains-supply native computers. But they do all work without issues in my experience.

I have to confess at this point I just grabbed the first small passive transformer I could find while ordering the replacement fuses. Hopefully it's adequate for testing.

megatron-uk wrote on 2024-03-19, 22:58:

I suspect for your purposes you don't need anything as big as the first and last.

but the middle one - is there transformer inside or not (how much it weights?), i.e. it provides proper SineWave or it's cheap, you can say even fake, SquareWave device. the first and the last one are proper SineWave devices, they weight respectively 3.5 and 7.5 kilos, because of all that copper wire inside. if that MW2P100 is heavy then it should be good too (I presume, but the weight is easy to fake).

mattw wrote on 2024-03-19, 23:05:

megatron-uk wrote on 2024-03-19, 22:58:

I suspect for your purposes you don't need anything as big as the first and last.

but the middle one - is there transformer inside or not (how much it weights?), i.e. it provides proper SineWave or it's cheap, you can say even fake, SquareWave device. the first and the last one are proper SineWave devices, they weight respectively 3.5 and 7.5 kilos, because of all that copper wire inside. if that MW2P100 is heavy then it should be good too (I presume, but the weight is easy to fake).

All I can say is that I have had it for around 10 years and it has worked perfectly for powering my MSX I'm all that time. Whether it is a true sine wave convertor or not, I have never had any problems with the MSX on it. Yes, it is fairly weighty, but as you say; that doesn't prove anything 😀

megatron-uk wrote on 2024-03-19, 23:28:

I have had it for around 10 years and it has worked perfectly for powering my MSX

at least it sounds durable, but maybe MSX is just not picky, I see recently the SineWave issue was discussed here:

Re: How to choose the right step up/down 110/120V to 220/240V transformer?

it's just with devices made in China, you never know what is inside - they can put paperweight or whatever inside just to fake the weight.

Tiido wrote on 2024-03-19, 22:48:

I think I will agree with mattw's thought on this, it likely was gonna fail with 100V too in this situation...

I read countless reports now it works with 220-240V so it has to be something else that caused the failure.

mattw wrote on 2024-03-19, 23:37:

I read countless reports now it works with 220-240V so it has to be something else that caused the failure.

And, again, that doesn't really matter. Apart from being "circumstantial evidence" as darry pointed out - it still leaves me SoL as far as the warranty goes, and if the unsolicited advice wasn't given then I would have waited till I had a transformer before even trying to plug it in. Which means any failure would have been warranteeable.

So can y'all please knock it off with the "it wasn't really anyones fault" blame avoidance game? It's meaningless, unhelpful, and at this point isn't going to change my perception of this.

InTheStudy wrote on 2024-03-19, 23:50:

It's meaningless, unhelpful

IMHO, it's very meaningful and helpful information for whoever is going to attempt fixing it, i.e. that there is very strong possibility the input voltage has nothing to do with the failure.

mattw wrote on 2024-03-19, 23:54:

IMHO, it's very meaningful and helpful information for whoever is going to attempt fixing it, i.e. that there is very strong possibility the input voltage has nothing to do with the failure.

That's really not the case.

He'll have a set of new fuses and a correct input voltage. If it blows again under those conditions, he'll have that information anyway. If it doesn't blow, the information is wrong and telling him would be a misdirection.

You don’t need to be a dick. I get that you’re upset about your synth being dead and I’m sorry but that’s no reason to take it out on me.

As I mentioned in my post, my experience just comes from working with the sc55, 88, and 1080. I just mentioned that I thought your model might have a universal transformer too. I googled sc-d70 and from what I read it seemed to have a universal transformer, but hey I spent all of five seconds on it while I was in the bathroom at work. I was just suggesting that I think it might have one and if so you can easily rewire it.

There’s no reason for you to be an asshole just because someone offers a suggestion you don’t like.

Sorry to Study, if we were wrong I obviously offer sincerest apologies and it's not a good thing to offer unhelpful advice.

That said - I personally have used a SC-D70 in the US and Australia, the same unit, no stepdowns.

From the manual, this was interesting:
Power Supply
AC 120 V, AC 230 V or AC 240 V
• Power Consumption
AC 120 V 10 W
AC 230 V 11 W
AC 240 V 11 W

To me, this indicates the unit can be used in any of these ACvoltages without issue, as has been my experience.

I'm no electronics expert, but to the best of my knowledge, a unit at the wrong voltage wouldn't power on for 2 minutes then blow, right? It'd be near instantaneous.

Anyway, regardless the unit has an issue. But obviously you do need to know the root cause for warranties and for solving the issue if the unit gets repaired.

There is a situation described in the manual as possibly damaging, where the inputs are put into a loop. Since it is stated that it blew when the PC was powered up, it leads one to considering if a hookup configuration similar to that may have been responsible.

Actually looking at those manual specs again, it's possible that the Japanese 100V units (or a subset) are a special use case - designed without switching power supplies. So the 117-120V units might be 'international' or export releases that are switching and functional 120-240V (presumably because it was cheaper to do so, others have mentioned them and indeed all Roland modules of the era being switching on VOGONS many times before), but the 100V units (which I think the OP has) may not be. Another possibility.

EDIT: The Japanese manual also only references 100V, not the multiple voltages. So my gut feel is the advice was incorrect in this case (although an easy mistake to make, in fairness), and I apologise for my part in that, Study. Happy to pay towards the repair cost or make some other contribution.

All of my Roland modules (sc55mk2, mt32 old, sc8820) are external PSU only, low voltage (typically 9v DC).

I have seen some later (8850 perhaps? I can't quite remember) with captive mains cables, but I would never assume a universal 100-240v capability unless the box is marked so.

In the case of the D70, Just because the rear panel has a c13 mains power socket doesn't mean it is universal voltage compatible - looking at the case it has no markings to confirm it one way or the other (which is bad form on behalf of the manufacturer, IMO).

megatron-uk wrote on 2024-03-21, 18:54:

All of my Roland modules (sc55mk2, mt32 old, sc8820) are external PSU only, low voltage (typically 9v DC).

I have seen some later (8850 perhaps? I can't quite remember) with captive mains cables

after 9V adapter in the early SC devices, they went to Internal Transformer, for example in SC-88Pro:

https://esher.ru/blog/899.html

which is universal in a sense that it has windings to support all possible mains voltages (there are pins on the Transformer for 100V, 120V, 230V and 240V as you can see on the picture from the above link) , but you need to set it manually with opening the device and solder the wire to the correct pin on the transformer.

megatron-uk wrote on 2024-03-21, 18:54:

In the case of the D70

please, note that SC-D70 and D70 are 2 different devices! now, SC-8850 and SC-D70 both use switch-mode power supply, all available reports online until this thread are that it's Universal and that actually makes a lot of sense for a switch-mode power supply. also, my understanding is the particular device from this thread worked for 2 minutes on 240V before it failed - if that is correct then it's another pointer that it's not the mains voltage. I mean if you plug 100V only device to 240V - it will smoke immediately not 2 minutes later.

Unless a device is explicitly marked as compatible with 1o0-240v operation I would definitely not assume that it is safe to use with any voltage in that range; whether it is equipped with a switch mode power supply, which should be okay, or not.

That is just asking for trouble.

Ok, RE: Manual - yes, my paper manual is a Japanese "100V Only" manual, like the sticker on the bottom.

The PSU is definitely a switched mode unit. FET + baby transformer.

The only thing plugged in to the device was the USB cable - as MIDI and Audio can both be transmitted that way, there isn't a need for anything else to hook it up. The MU-50 was also on, but that was plugged into the Alpha.

There is no visual sign of physical damage to any component (i.e. no black smoke escaped, only the magic), and the only thing I've verified to definitely have burned out is the input fuse, as I can't test past that without replacing it. I now have nine of them in a box with the synth, ready to go to a local tech along with the MU-50 (for battery replacement with a holder).

Spikey wrote on 2024-03-21, 15:02:

Sorry to Study, if we were wrong I obviously offer sincerest apologies and it's not a good thing to offer unhelpful advice.

Reflection achieved as requested, I can't ask for any more than that. As for paying towards repairs - don't sweat it. Either it'll be a cheap fix in which case I'll manage; or the thing is completely toast in which case it doesn't matter any way. Regardless, there's no need for you to put out your own money for an honest mistake, just as long as we all agree never to make it again! 😁

I'm no electronics expert, but to the best of my knowledge, a unit at the wrong voltage wouldn't power on for 2 minutes then blow, right? It'd be near instantaneous.

Depends on the design. Something like a transformer, bridge rectifier and filter cap? (A la SC88) that's going to dump fixed ratio x input voltage into the circuit, so if you give it double the voltage; all of a sudden your 5V IC gets 10V and everything is dead in under a second.

With something like a switched-mode, it should output the "target" voltage regardless of the input, however - if the input voltage is at or near the absolute maximum rating of the design or one of the components, it's possible it will work until something takes it just that little bit over; and then something overheats, or otherwise fails, and *then* it dies. The simplest answer is still a weak fuse.

*Or* there was something else already on the verge of failing due to age, and this was just the "straw" as Matt suggested. I'm still highly suspicious of this theory. Occams Razor seems to apply. Regardless, the only way to know either way is to replace the fuse and see what happens; and since I know someone who can do that; we'll let him take the reins. If anyone wants to start a pool, go nuts - as long as I get half the pot as "licensing fees". Also, put me down for £2 for "out of spec cap triggered fuse". I think that's a wrong answer, which means it's probably right.

Regardless; the three takeaways I think are useful from this.

1. Don't dissuade people from taking the safer path if that's what they're comfortable with; even if you think you know better.
2. Read threads to the end before replying, just in case your comment ends up being the gasoline on a fresh match.
3. Don't plug a Japanese SC-D70 into 216-253V mains without using a step-down transformer, unless you actively like to live dangerously or can afford to casually replace it.

As I say, 9 fuses have arrived, but I'm waiting on the transformer before I give it to the Tech. Wish him, me, and it, luck!

Also, long day at a conference tomorrow, but my weekend is going to be FF7 PC with the MU-50 (cheering myself up by living my childhood fantasy) and hopefully having a crack at patching USB Gadget into mt32-pi. Wish me luck with those too.

Good luck for sure on all counts. I do have a SC-D70 that I'm unlikely to use again, one of the switching ones, and I can send it to you, if yours is dead.

Spikey wrote on 2024-03-23, 10:41:

Good luck for sure on all counts. I do have a SC-D70 that I'm unlikely to use again, one of the switching ones, and I can send it to you, if yours is dead.

That's really, really sweet of you - but I wouldn't be able to accept a $300AU gift from someone even IF I thought it was fair for you to "make good", which I don't. We're cool as a Cactuar, Spikey. 😀

I'm optimistic, so let's just see how it goes with the tech next week. In the meantime, I'm gonna take a look at printing a couple of half-rack cases, for the MT-D47 and the World's Worst Recording Studio. 😀

Optimism, Captain!

Depending on where the fuses were sourced from, it might be good to test one of them. I have seen some frightening (to me) allegations of some unbranded (or possibly counterfeit branding) not being fast blow as advertized or even not blowing at all (within a sane timeframe) while passing significantly more current they should.

EDIT: Sorry if this is FUD/paranoia, but this thought (and others) has had me considering a bench PSU with a current limiter.