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DIY Stompboxes => Building your own stompbox => Topic started by: Mark Hammer on July 28, 2022, 06:26:41 PM

Title: 120 and 240VAC: how compatible?
Post by: Mark Hammer on July 28, 2022, 06:26:41 PM
I bought a second hand Roland D-110 unit this afternoon for what amounts to a song ($35!!).  The seller had a custom connector where the power plug ought to have been.  He assured me the unit was in good working order, but he hadn't used it in a while.  The guy is a bit of a tinkerer, but from his shop he was clearly a professional in such matters, and apparently installed big home theatres for a living.

I clipped off the custom connector as he suggested, and grafted on a 3-prong plug, identifying first which lead was which on the cable coming out the back of the module.  Verified that all plug prongs are connected appropriately, but the unit would not power on.

Then I noticed on the back of the unit that it wants 240VAC.  Is this a problem, and if so how would I fix it?
Title: Re: 120 and 240VAC: how compatible?
Post by: stallik on July 28, 2022, 06:53:55 PM
Step up transformer  would be the easiest solution. It must be possible to to convert the power supply to 110v but I bet it's not going to be as simple as just a transformer replacement. Either way, it'll increase your investment in the unit. :(
Title: Re: 120 and 240VAC: how compatible?
Post by: Mark Hammer on July 28, 2022, 07:06:01 PM
I sent the seller a note asking about the power situation.  He seems like a decent guy, and we had a very nice chat, but I don't expect to get a reply from him as quickly as I get one here.
Title: Re: 120 and 240VAC: how compatible?
Post by: mozz on July 28, 2022, 07:20:28 PM
If it has a power transformer, sometimes they have windings for both 120 and 240. But it may have a different transformer for each voltage.
Title: Re: 120 and 240VAC: how compatible?
Post by: Rob Strand on July 28, 2022, 07:24:08 PM
Upfront it's not 100% clear what voltage the transformer is inside.   The guy may have done something weird to it.

Assuming everything is factory:

A step-up from 110V to 240V would work.  These can be isolating or non-isolating.  Both will work.

The service manual (p8) shows the transformer, **
https://www.synthxl.com/wp-content/uploads/2017/12/Roland-D110-Service-Notes.pdf

It looks like a different transformer is used for each voltage - since a different p/n is given for each voltage.    The way the mains wiring is drawn looks a bit ambiguous.  There is an "all"  white in terminal S02, but also an unconnected terminal with colored wires for each voltage on S03.  The way the transformer is drawn makes it looks like the S03 windings are taps.  A terrible way to draw mains connections.    The transformer might even have a thermal fuse inside, since there's no mains fuse.

You could replace the transformer but the trick then is getting the correct secondary voltages and the correct VA rating.   The extra secondary winding to the 5V regulator (yellow wires) makes it more difficult to find an off-the shelf transformer.  Also you don't know what proportion of VA is assigned to the +/- 15V part of the circuit and the 5V part of the circuit.  The uncertainty of the thermal fuse is another hassle.
[measuring the primary and secondary resistances can help put bounds on the VA ratings, provided the primary ans secondary voltage of the transformer is known.  The physical size helps as well.]

You would also have change the mains plug (or plug+ cable) to a 110V type.  It is generally illegal (and a hazard) to use the wrong type of plug on equipment.

A factory transformer might be hard to get and expensive.  I guess you could contact Roland.
A step-up transformer could also be expensive but as far a minimizing work it's an easy way forward (*if* the unit is a genuine 240V unit.)


** Edit
Maybe the transformer wire colors or markings will help you identify the transformer voltage.
Title: Re: 120 and 240VAC: how compatible?
Post by: Toy Sun on July 28, 2022, 09:22:40 PM
I lived in Europe for 10 years and used a lot of US-purchased equipment in various ways. It's true the best thing is to find that the internal transformer is multi-tap and get that working. It's the way it was designed and it all stays stock. But sounds like that's not an option.
The other end of the spectrum is to use a standalone transformer, ideally with built in cables and sockets that removes all doubt and risk of misconnection (so that would be a US NEMA male plug on the 120v side and a EU Schuko socket on the female side. Grounding is nice, too, but I've used some kludgy stuff for that before.
In between is where you are now, so just work carefully and thoughtfully. A mistake is going to be a bummer...
Title: Re: 120 and 240VAC: how compatible?
Post by: idy on July 28, 2022, 10:18:27 PM
If the guy is a "tinkerer" you never know, it could already be converted, and feeding it 240 might smoke it. Just a "you never know." requires a talk with him or some serious recon.
Title: Re: 120 and 240VAC: how compatible?
Post by: anotherjim on July 29, 2022, 04:12:13 AM
Odd that a Japanese company would make it so it needs different transformers. I heard that the Japanese islands have different power grids depending on which (foreign) company installed the first electricity supplies in a region.

(https://i.postimg.cc/SKx2N3M8/Screenshot-2022-07-29-at-09-06-00-Roland-D110-Service-Notes-pdf.png)
The lower 100v/117v primary taps say "Nothing". Presumably, no wire exists in those cases.
Title: Re: 120 and 240VAC: how compatible?
Post by: matopotato on July 29, 2022, 05:34:15 AM
240 vs 110 implies to me that there could also be a variation in frequency? 50Hz for 230/240 networks at least in most of Europe, and in US (&Canada? ) 60Hz for 110 supply.
Nooooo idea if this matters in this case though.
Title: Re: 120 and 240VAC: how compatible?
Post by: Mark Hammer on July 29, 2022, 08:07:50 AM
Heard back from the seller this morning, who said he hadn't used it in so long he couldn't remember exactly, but would look around to see if there was some sort of adapter he had used.  He WAS the person who adapted the end of the power cable in the first place.

As someone once said, we'll see what happens.
Title: Re: 120 and 240VAC: how compatible?
Post by: amptramp on July 29, 2022, 08:16:10 AM
Getting a transformer with supplies for ±15 and +5 may be difficult but on a number of occasions before, I have used two transformers to replace one with the advantage that they would be standard units.

There is one additional suggestion: there are a number of local surplus shops that sell used Lambda power supplies.  I am currently using a single unit with a 5 VDC @ 3A output plus ±12 - 15 VDC @ 1A to power the old 1926 radio I finished last winter.  You could get the same or separate 5 volt and ± supplies and bypass the internal regulators.  Since the existing ones use 7805/7815/7915 regulators, the current should not be a limiting factor.  You can keep the existing EMI filter/switch module.
Title: Re: 120 and 240VAC: how compatible?
Post by: ElectricDruid on July 29, 2022, 09:12:17 AM
I had the same problem in reverse on a Korg Polysix - it was US voltage, and I wanted European 240V.

As others have suggested, it turned out that the internal transformer had taps for both settings, so it was just a question of wiring it up differently.

You might be lucky. Open 'er up and let's have a look!
Title: Re: 120 and 240VAC: how compatible?
Post by: Kevin Mitchell on July 29, 2022, 09:58:29 AM
According to the service sheet (https://www.synthxl.com/wp-content/uploads/2017/12/Roland-D110-Service-Notes.pdf), they produced these with 4 different transformer options.
110v, 117v, 220v & 240v
edit - I see anotherjim covered this

Transformers with the additional tap for 5v aren't common. The reason for the extra lower voltage secondary is to prevent the regulator from overheating getting rid of the excessive voltage - a popular issue with old synths like the Prophet 5.

If I had that unit on my bench I'd use a 34Vct transformer and replace the 5v regulator with a DC-DC converter. Like this one;
https://www.mouser.com/ProductDetail/Murata-Power-Solutions/OKI-78SR-5-1.5-W36-C?qs=uJpRT2lXVNXJP%252Bo08dQqJQ%3D%3D

You would then have to jumper the inputs of the 7815 to the 7805 since the other rectifier would no longer be used.

Title: Re: 120 and 240VAC: how compatible?
Post by: Rob Strand on July 29, 2022, 10:28:08 PM
My point was the transformer had different part numbers for each mains voltages.
That means the transformer is unlikely to have mains/primary taps.

Interesting, a transformer is for sale:

https://reverb.com/item/44898862-roland-d110-power-transformer-245-517c-sec-35-0-35-volts-and-8-5-volts
(https://i.postimg.cc/yJTKCWvq/Roland-D110-Power-Transformer.webp) (https://postimg.cc/yJTKCWvq)

Roland p/n;   245-517C
Primary:    Single winding, 117V,   thick white/yellow wires
Secondary 1: 35.5V 2xRed and presumably black is ct.
Secondary 2: 8.5V  2xYellow

*** only single primary winding shown.
Voltages are readable from the label pic.

*** the yellow + white option is not in the list in the service manual!
but at least the 517 in the Roland part number matches 117V.

The transformer is a low noise R-core type.

Hard to judge VA from the pic. However the service manual indicates 12W so it could be a 20VA R-core transformer.

Proportion of VA between two secondaries unknown as no currents given on label.

I doubt the transformer is 35V-0V-35V like the ad. says.  That's too high for a +/-15V rail.
More likely is 35.5V ct.  ie.  17.75V-0V-17.75V.   
The 8.5V winding looks fine 7.5V or 8.5V windings are very typical for 5V supplies.



Another 117V here but with a green primary wire
https://www.keyboardkountry.com/roland-d-110-transformer/


Standard Catalog:
http://kitamura-kiden.co.jp/common/img/product/pdf/01_Rcoretrance.pdf

They make 10VA, 20VA, 25VA ...


Here's a 245-516NO,
pic: 100V primary, blue and white primaries
https://1.bp.blogspot.com/-Q1B_mq2CXnk/VSIvVwueX6I/AAAAAAAALr4/7JFSw58fhyM/s1600/D110_2.jpg

The part number and Blue wire both match the service manual.

The label is marked 2x17.5V 18VA
Nothing marked for the 8.5V secondary so no idea of rating.
Also no idea if 18VA applies to both secondaries or just the 17.5V-0V-17.5V secondary.


Just for completeness.  Don't know the voltage but the pic here shows the *three* transformer primary wires (S01, S02, S03) = (Brown, White, Red).
https://forums.syntaur.com/t/d-110-power-switch-assembly/609

When the transformer only has two wires S03 is left unconnected.

So there is a case where there are three wires like the service manual shows, but there's also two wire cases (which is where the service manual isn't so clear).   No idea what S03 does.

Some transformers have a Faraday shield but it would be very dangerous to assume S03 is that without proof!
I'd go so far to say it's not a Faraday shield.

Title: Re: 120 and 240VAC: how compatible?
Post by: Slowpoke101 on July 30, 2022, 02:04:48 AM
I am just wondering if Mark has opened up the unit in question and had a look at what transformer is actually in there. The original owner may have already replaced the 240V transformer with a different type.
Title: Re: 120 and 240VAC: how compatible?
Post by: Rob Strand on July 30, 2022, 04:42:58 AM
QuoteThe lower 100v/117v primary taps say "Nothing". Presumably, no wire exists in those cases.
OK I think I know what's going on now.

The 100V and 117V only have two wires.  The transformers for 100V and 117V have different part numbers.

The 220V and 240V models have three wires.  The same transformer p/n is used for each. 
The white wire is primary/mains common tap.  The brown wire is the 220V tap.  The red wire is the 240V tap.
The wire which goes to S01 is the tap which is used.
The wire which goes to S03 is the unused tap.   S03 is just a dummy connection to hang the unused tap.

Everything seems consistent with pics and service manual.

The only inconsistency is the wire color used for the mains on the 117V transformer.  It seems to vary  (Green, Yellow) and never matches the grey color in the service manual.  (Could speculate the other colors are 110V and 120V but the p/n is the same as the 117V and the transformers are marked 117V!)

Title: Re: 120 and 240VAC: how compatible?
Post by: anotherjim on July 30, 2022, 09:18:41 AM
I'm always pleasantly surprised if transformer wire colours conform 100% to the schematic. Those colours can change between production runs. Manuals don't get updated for it, presumably official service centres get a memo about it.
Anyway, that's why I picked up on the 3rd wire as an easy tell whether you have a 220/240 traffy, no matter what the colours might be.
Title: Re: 120 and 240VAC: how compatible?
Post by: anotherjim on July 30, 2022, 09:28:44 AM
Another thought, don't some 110v/60Hz places get x2 balanced supply phases so heavy loads can run off 220v without needing heavier wiring?
Title: Re: 120 and 240VAC: how compatible?
Post by: Mark Hammer on July 30, 2022, 12:52:06 PM
Quote from: Slowpoke101 on July 30, 2022, 02:04:48 AM
I am just wondering if Mark has opened up the unit in question and had a look at what transformer is actually in there. The original owner may have already replaced the 240V transformer with a different type.
1) I've been opening up stuff to "see what's in there" since about 1956.  It's a bad habit.  So, rather surprising that I haven't opened it up yet.

2) The previous owner had clipped the normal plug end off the power cable, and replaced it with a pin jack like what we used to see on the end of the power-supply cables in our computers that would go to hard and floppy drives.  At first, I thought it was just for some sort of custom power-sharing thing, but after corresponding with him, realized it was for using an adapter cable that would plug into a step-up transformer unit.  He looked for those things, but so far has been unable to re-locate them.  He did do a bit of an Amazon search on my behalf and found some suitable step-up units for under $25.
Title: Re: 120 and 240VAC: how compatible?
Post by: PRR on July 30, 2022, 06:29:25 PM
Quote from: anotherjim on July 30, 2022, 09:28:44 AM..don't some 110v/60Hz places get x2 balanced supply phases so heavy loads can run off 220v .....

Not on the same outlet.

My lamp outlets are 120V. My dryer outlet is 240V.(*) I'm sure Mark wants a Canadian lamp outlet (120V) rather than have an electrician bring a 9600W dryer outlet to his playing room for a mere 25W load.

(*) OK, my cooker is fed by a 120V/240V system, historically so 220V burners could be run at part-power and so stock 110v clock/timers would work; incidentally for a hi-power 110V coffee percolator or clothes-iron in a vintage kitchen which may not have much other electricity. Again, not the way Mark should go. The plug-socket set alone for a 4-wire stove costs more than his whole synth.
Title: Re: 120 and 240VAC: how compatible?
Post by: Rob Strand on July 30, 2022, 06:40:15 PM
Quote2) The previous owner had clipped the normal plug end off the power cable, and replaced it with a pin jack like what we used to see on the end of the power-supply cables in our computers that would go to hard and floppy drives.
Another DIY death trap!
Title: Re: 120 and 240VAC: how compatible?
Post by: Rob Strand on July 30, 2022, 09:16:17 PM
Quote from: anotherjim on July 30, 2022, 09:18:41 AM
I'm always pleasantly surprised if transformer wire colours conform 100% to the schematic. Those colours can change between production runs. Manuals don't get updated for it, presumably official service centres get a memo about it.
Anyway, that's why I picked up on the 3rd wire as an easy tell whether you have a 220/240 traffy, no matter what the colours might be.
Very true.   Documentation from Japan is pretty good, usually brief but concise.

Philips consumer products often had many versions.   They *did* have the documents for each version however more often than not the version didn't actually match the exact product.   Not really Philip's fault, users didn't know what version they had, or that there was a different version.   I remember once they updated one of their tweeters to a current model driver and it was about 3dB more sensitive than the original.  The documents accurately showed the change but engineering-wise it was wrong!  30 years later a guy on the web measured the frequency response and was wondering why it wasn't flat!
Title: Re: 120 and 240VAC: how compatible?
Post by: Ice-9 on July 31, 2022, 04:08:17 AM
Mark, The only way to know what is going on and how to sort it out is to open up the rack and have a look at what has been modified internally (or not). I wouldn't be wiring any mains up to the unit until I knew what was inside, when it comes to mains voltages, never trust someone's vague memory of what they have changed. Check this out for yourself after all it is only a few screws to open up the box. 

Once open you it will be obvoius what transformer is fitted and what you need to swap. Rob posted a link to a transformer on Reverb.com for about $10 if you didn't see that a few posts above. 

It's pointless trying to work out how to fix something if you haven't even looked inside yet to see what you might or might not need as it might be correct for 110v already. Get that box opened up :)
Title: Re: 120 and 240VAC: how compatible?
Post by: matopotato on July 31, 2022, 05:15:29 AM
Quote from: Ice-9 on July 31, 2022, 04:08:17 AM
Mark. <snip>  Get that box opened up :)
...and post some pics. We like 'em...
Title: Re: 120 and 240VAC: how compatible?
Post by: anotherjim on July 31, 2022, 06:37:24 AM
Are these the computer-type connectors used?
(https://static4.arrow.com/-/media/arrow/images/research-and-events/articles/0920/molex-connectors-image.png?mw=734&hash=9FA81BED8753F6416BEF25F59173EC23)

I don't think there is anything badly wrong with using those Molex-type connectors for AC power (within the designed rating). IIRC, you could get insulating boots to cover the rear wire entry. For instance, the spin motor of the old 8" floppy drives was AC mains powered off a 3pin Molex.
(https://cdn11.bigcommerce.com/s-a1x7hg2jgk/images/stencil/608x608/products/21320/120808/shugart-801-8-inch-internal-floppy-disk-drive-5.35__39883.1490181565.jpg?c=2)
The thing with them is you really must use a proper crimping tool and also the removal tool to correct mistakes. And, of course, make very sure the connector can't fit in any that it shouldn't. The cost of an official crimping tool will make your eyes water.

Anyway, all that is FYI. It has to be better to use a normal AC connector, even in a rack.



Title: Re: 120 and 240VAC: how compatible?
Post by: anotherjim on July 31, 2022, 06:51:58 AM
Quote from: PRR on July 30, 2022, 06:29:25 PM
Quote from: anotherjim on July 30, 2022, 09:28:44 AM..don't some 110v/60Hz places get x2 balanced supply phases so heavy loads can run off 220v .....

Not on the same outlet.

I didn't think it would be, but a purpose-built studio might include a 240v feed to allow for foreign gear? I don't know as the situation doesn't arise where I live, but 110v is standard for industrial power tools so 240v/110v transformers are easy to get and cheap if we want 110v (ignoring the 50-60Hz difference).
My point is that it might have been used at 240v but couldn't use a domestic type outlet hence the "non-standard" connection.

Title: Re: 120 and 240VAC: how compatible?
Post by: Ben N on July 31, 2022, 10:19:31 AM
The part number on the tranny in the Reverb setting that Rob linked clearly shows the part number corresponding to the 117V transformer on the schematic. Seems a pretty simple matter to just look at the legend on the part, regardless of the color of the primary wires.
Title: Re: 120 and 240VAC: how compatible?
Post by: PRR on July 31, 2022, 04:23:18 PM
Quote from: anotherjim on July 31, 2022, 06:51:58 AM...where I live, ..110v is standard for industrial power tools so 240v/110v transformers are easy to get and cheap...

The yellow job-site boxes?
(https://assets.alliedelec.com/f_auto,q_auto,c_scale,w_400/71094726.jpg)
That is very specific to UK code and a few UK-derived markets? I'm not even sure they do it in Hong Kong or Australia?

That's 230V:110V. Mark needs the other way. Yes the iron is reversable... but too hot this summer to mess with it.

And 110V center tap is a funny beast. Yes it is only <70V to dirt but a lot of gear never contemplated both sides being "live". Aside from hum, I have read of fancy audio making a conflicting assumption and smoking a many-$K DAC.

Mark wants (maybe!!) 230V. He can sure take that off his dryer circuit but the cable has to be big enough to blow a 30 Amp breaker, so not that lamp-cord. Under NEC code such a circuit must be a single outlet (OK today but what if more 230V bargains follow Mark home?) And again a US/CAN dryer circuit is effectively cent[re|er]-tap. And we don't know what mods the previous genius did.

I did find out what is inside the yellow box, and where the earths should run.
https://www.youtube.com/watch?v=2t_JR0CxctQ
I had heard the box was filled with sand+binder for control of heat and fire, but maybe not in this model?
Title: Re: 120 and 240VAC: how compatible?
Post by: PRR on July 31, 2022, 04:53:15 PM
This is like what he should want (assuming the 230V notation is correct):
https://www.aliexpress.com/item/2251832799825022.html?gatewayAdapt=4itemAdapt
Under 20 bucks, shipped by slow-boat. I don't know the trustworthiness. He may be safer going to the local international airport traveler's store so he knows who to blame if it burns-up.

Unusually, this one goes both ways. Set the switch!!

There is ANOTHER converter rated 240V:120V 1,000 Watts, in a smaller box which sure can't be a 1KW winding. These are only for "heater" loads, irons and hair-dryers. They switch on/off rapidly to give the heating effect of 120V from 240V power.
Title: Re: 120 and 240VAC: how compatible?
Post by: Rob Strand on July 31, 2022, 07:26:58 PM
QuoteAre these the computer-type connectors used?
...
I don't think there is anything badly wrong with using those Molex-type connectors for AC power (within the designed rating).
OK for inside equipment but not for external cables.   External cables and connectors have a whole heap of safety requirements.  That's why most companies stick to standardized mains connectors.

As an example imagine someone cuts their (external) power cable and joins them back again using a terminal block
https://www.cdlmicro.co.uk/cdl-tbk-10a-10a-12-way-terminal-blockcable-connector-strip-for-electrical-connections-black.html
Suppose the terminal is mains rated (I don't know if that one is).   While it's OK to do mains wiring inside equipment with a terminal block it's not OK do mains wiring outside of the equipment using the same terminal block.  Same goes for connectors.

Moreover, if you submitted a product for safety testing with a terminal block joining the wires it would be rejected
for sure.   That means the method of construction doesn't comply with safety standards.

Even from a common sense point of view many connectors aren't safe if pulled or if they are exposed to humid environments.

QuoteThe cost of an official crimping tool will make your eyes water.
Indeed, some have insane prices like > $1000.   If a cable manufacturer doesn't have the right tools it can blow-out costs for small runs.
Title: Re: 120 and 240VAC: how compatible?
Post by: Toy Sun on December 24, 2022, 02:38:03 AM
Quote from: anotherjim on July 31, 2022, 06:51:58 AM
Quote from: PRR on July 30, 2022, 06:29:25 PM
Quote from: anotherjim on July 30, 2022, 09:28:44 AM..don't some 110v/60Hz places get x2 balanced supply phases so heavy loads can run off 220v .....

Not on the same outlet.

I didn't think it would be, but a purpose-built studio might include a 240v feed to allow for foreign gear? I don't know as the situation doesn't arise where I live, but 110v is standard for industrial power tools so 240v/110v transformers are easy to get and cheap if we want 110v (ignoring the 50-60Hz difference).
My point is that it might have been used at 240v but couldn't use a domestic type outlet hence the "non-standard" connection.

I've worked in studios in the EU (France) that had 110v outlets for using US gear. Pretty cool. Also, in Brazil, they have both 220v and 110v kind of confusingly mixed together, I don't remember the details, but was advised to be very careful plugging in. We always asked. I was touring with a Walter Woods amp at the time, which had a nice 110/220 switch on it, but also an amp that I did not want to blow up!

The showers had a water heater right in the showerhead, complete with two wires coming out the the plaster wall and going into the thing. I got a shock while reaching up to wash my hair. Exciting! Looked like this...

(https://i.postimg.cc/3kSvS16Y/WI5-Ddnk-F98ix2-Vge-LMd-Uz8-Wb-EDNFh-Emqy-Ti-P-F0kno-jpg.webp) (https://postimg.cc/3kSvS16Y)