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Changing Input Voltage on a Roland HP107e-RW Electric Piano

Making a keyboard from the UK run on USA power

Electrical power grids around the world provide electricity to their end users at a handful of different voltages and frequencies. For example, consumer electronics in the USA typically operate on 100-120 V @ 60 Hz while in the UK most everything runs on 220-240 V @ 50 Hz. In addition to the voltage and frequency variations, there are a handful of power cable plug shapes that various regions use too. People generally don’t have to concern themselves with all this information unless they are traveling or moving abroad and taking their electronics with them.

Friends of ours recently gave Katie a Roland HP107e-RW electric piano they had purchased while living in the UK. When they moved back to the USA, they brought the piano and quite a few other items with them that all ran on 230V. To power those items on the US electrical grid, they purchased a step up converter.

rear product label with model number and serial number

This particular model is the HP107e-RW. There are probably several other similar models for which this modification would work.

Instead of buying a bulky step up convertor to run the piano at our house, I wanted to convert the piano to run natively on the US electrical grid. In order to make this possible I needed to do 2 things:

  1. Change the shape of the power cable plug from UK style (Type G) to NEMA 1-15 ungrounded (Type A)
  2. Change the input voltage from 220-240 V to 110-120 V

Changing the power cable plug was easy. The power inlet on the piano is an IEC 60320 C8. Many of the electronic devices I own use the Type A cable I needed to replace the Type G cable. Swapping out the cable was simple, but that only changed the shape of the plug, not the voltage.

Interestingly, the Type G plug was actually a wrapper around the head of a Europlug (Type C) plug. This was perhaps a cost-saving measure.

an opened Type G plug

A sneaky Europlug hiding inside the Type G plug.

Changing the input voltage was a little harder. Some consumer electronics have little voltage switches next to the power inlet that are easily accessible on the outside. I didn’t see one of those, but sometimes the switch (or jumper) is inside the chassis on the power PCB.

To get a look at the power situation I opened up the top of the piano. That required removing 8 screws grouped in 4 pairs along the top rear of the piano, then sliding the top board forward and lifting it off. There are no wires or other connections made to the top board.

rear of piano with arrows schowing locations of screws to be removed

The blue arrows indicate the 8 screws that need to be removed to take the top off the piano.

After opening up the top I found this beefy power transformer staring back at me. There was no super convenient voltage switch, but surprisingly the input pins on the transformer were labeled—an easy solution! The fix was simple…desolder the black hot wire from the 230 V pin and resolder it to the 120 V pin.

internal power transformer with voltage labels

The label on the transformer indicates what voltages are expected on the input pins.

CAUTION: Before beginning this surgery, I recommend isolating the transformer from everything else. Unplug the input power cable from the wall oulet AND disconnect the output power cable connector from the main PCB. As with all things electrical, you could kill yourself if you don’t know what you are doing. Be safe! Be smart!

Interior look at cable connection from transformer to PCB

Out of caution I unplugged this cable connector before unsoldering and resoldering the cable to the transformer.

After moving the hot wire to the correct input pin, reconnecting the cable connector to the PCB, reattaching the top board, and plugging in the new power cable the piano fired up perfectly.

Let me know if this helped you. If you fried your keyboard or yourself, sorry, I am not responsible for your mistake. Better luck next time! 😉

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Dating Advice

This is the best dating advice I can give you. It may not be what you’re looking for. I’m sorry.

I write songs, then document them on my computer in plain text files. As I’m working on a song I may revise it at a later date or create alternate versions. The dates I start and edit my songs are valuable to me for both posterity sake (i.e. copyright), as well as sorting purposes.

Dating Problems

The easiest way to manage the dates would be not to worry about the date. I could simply depend solely on the file meta data. Most modern operating systems automatically attach “created on” and “last modified” dates to files, so I could just do nothing and hope that everything is kept in order.

screen grab of the meta data of a text file

Storing valuable info in the meta data is a good way to make sure you never have accurate data.

But that system only works as long as the meta data doesn’t get stripped from the file. Unfortunately, for reasons I don’t fully understand, I’ve found that sometimes it does get lost.

Another easy way to keep track of this stuff would be to write the date at the top of the file like so:

My Next Amazing Song
by Scott Troyer
Written: March 24, 2012

Verse 1:
Love is like a dove…

But, if I save that file as “My Next Amazing Song.txt” and throw it in my “Unfinished Songs” file with my other works-in-progress, there’s no way to quickly sort the songs based on that date.

screen grab of unsorted files in OS X

Boo. Just, boo.

The Dating Solution

Instead, I include the date in the name of the file in the no-nonsense year-month-day format. (e.g. “My Next Amazing Song 2012-03-24.txt”)

Why do I date them with that format?

Dating Made Better

In the US, dates are often written MM/DD/YY, while in the UK dates are typically written DD/MM/YY. Occasionally the formats are flopped resulting in either YY/MM/DD or YY/DD/MM. Sometimes the year has 4 digits, sometimes 2. All of this causes confusion. Does 05/04/06 refer to May 4th or April 5th? And is that 1806 or 1906? Or is the year ’05? Shenanigans!

This is why some smart people created the ISO 8601 date format, which specifics that when specifying the year, month, day, it should be written YYYY-MM-DD. (At least until the year 10000 when we’ll use 5 digits for the year, but I doubt the human race can manage not to destroy ourselves before then, in which case we won’t need to worry about what the date is. I digress.)

So, clearly, YYYY-MM-DD is the best way to assign dates. In fact, as a reminder I create a little retweetable poem.

Need proof that YYYY-MM-DD is the best?

Test the OS

Let’s pretend the future chart topper “My Next Amazing Song” was first created on January 3rd, 2010, then revised on February 1st, 2011 and again on January 2nd, 2012, resulting in 3 versions of the file. If I name the 3 files using the 3 different methods DD-MM-YYYY, MM-DD-YYYY, and YYYY-MM-DD, this is how computers will alphabetically sort the files.

screen grab of how OS X sorts filenames with different date formats

The final mix of “My Next Amazing Song 2012-03-24.txt” is so hot! Can’t wait for you to hear it…


As you can see, YYYY-MM-DD is the only format that sorts the files chronologically. If we used DD-MM-YYYY, files would be grouped by the days first, months second, and years last — a total chronological disaster. And if we used MM-DD-YYYY, all the January files, regardless of year, would come first, then all the February files, etc. — a little better, but still a mess. YYYY-MM-DD puts the files into the order they were created.

Final Notes

  • If you’re wondering whether 2 digits would be sufficient for the year instead of 4, definitely read up about Y2K. Around the turn of the century, YY vs. YYYY was kind of a thing.
  • This date format works with all sorts of files types, not just plain text files. I often bounce mixes of recordings with the YYYY-MM-DD date in the name so they appear sorted the right way in iTunes.
  • For even better chronology, try putting the date before the name of your file. (e.g. “2012-03-24 My Next Amazing Song.txt”
  • None of this will make you a better songwriter, but at least your songs will be organized.