01/W Power

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This is one of those round, thin, lithium 3-volt batteries. One technician said batteries are shipped measuring 3.2 volts and are considered dead at 2.8v. For maximum battery life, keep spare batteries cool or cold. (Some people keep batteries in their refrigerator, but probably not the freezer). Don't keep them in a warm place (40 degrees C / 104 degrees F or warmer).

The Other Battery
There is a different battery on the PROG/SEQ DATA card that plugs in the back of the 01. Click here for information on that battery.

Battery Life
How long your battery lasts seems to depend on which model of 01 you have. Batteries in 01s with a disk drive seem to last longer than batteries in 01s that don't have a floppy. Why?

01s with a disk drive (fd models) save edits made to Global settings, Progs, and Combis. (You are expected to save sequences to disk yourself). An fd battery can have a life exceeding 9 years.

01s without a disk save all that plus sequences. This may shorten battery life in non-fd models.

Warning Message
A "Battery Low (Internal)" message is supposed to appear when the battery should soon be replaced. There has been a report that a battery died without displaying any messages, and all their custom Progs & Combis were lost (since they hadn't been saved to disk). Lesson: Back-up your work to floppy or to a computer using a SysEx MIDI Dump..

When "Battery Low (Internal)" appears, the manual says "Contact your dealer, or a nearby Korg service center." However, reports are that it is easy to change the battery yourself except for all the screws you have to remove and re-install.

I have no personal experience with this yet, so I am working from reports from others. It appears that opening the 01 may be easier with some models than others. One user claims to have changed the battery in 10 minutes simply by opening the back. Other models require you to go in from the bottom. You may want to consult the disassembly instructions as a guide to how to get inside.

The battery is mounted on the main circuit board. Simply replace the battery, re-assemble your 01, then re-load everything you saved to disk (or the external MIDI device).

User Reports
1: "The battery is easy to get to, is not soldered in and is a common type: CR2032. You have to remove the 20 screws or so that hold metal bottom on, and then the battery is visible on the motherboard. It's in a holder, so you can slide it out with your finger." [ee]

There's a photo page that Rafael supplied [2001Apr02]:
http://www.alba.hu/rafael/images/tech/korg01wpro_repair.jpg

Ed Edwards reported: "The battery is dimly visible in the upper right of the photo. But, you really don't need this picture to find the battery. Just turn it upside down, take off the back and you'll see the main board.  The only thing that looks like a disk battery in a disk battery holder is the disk battery! You
can push it down and then toward the open side of the holder to slide it out. And, get this - I had mine out for over 3 minutes and the 01 retained my patches! Maybe there's a storage capacitor that keeps the CMOS voltage up, but I was surprized." [01May01ee]

Technical Theory
Essential data is stored in two SRAMs (IC30, 31 wired as 32Kx16). When the 01 is turned off, a circuit automatically switches the SRAMs over to get power from a battery. There is a charging circuit that re-charges the battery while the 01 is turned on. (The 01 must be turned on, not just plugged in the wall). While power is off, the battery supplies power via the "VOUT" line. The battery charging circuit (IC33) includes a comparator (IC32) that sends a signal (INT BAT) to the CPU to display "Battery Low (Internal)" if the battery voltage drops too low.

This information comes from documentation for the 01/Wpro and proX. I suspect this information is identical for all 01/W models, but this has not been confirmed. Be very careful when working around power supply circuits. Using wrong parts or making other mistakes can result in damaged equipment or even a fire. BE CAREFUL!

On my US model, the 01 power cord has a female connector on the 01 end. It is the same as power cord commonly used with desktop personal computers.

Internally, from the 01 socket the power goes through filtering circuits (inductors, capacitors) and a fuse on the way to a transformer. The transformer has various taps that are connected depending on the country the 01 was being made for.

There are two output circuits from the transformer, one for generating plus and minus (+/-) 12 volts, and one for generating +5 volts. These use standard voltage-regulator circuits and ICs. Each transformer circuit has a series fuse followed by a full-wave (bridge) rectifier. The rectifier output has filter capacitors on the way to 3-terminal regulators. The 12-volt circuit uses a 78M12 and 79M12. The 5-volt circuit uses a PQ05RF2. The 5-volt regulator also feeds a voltage inverter circuit to power the EL backlight for the LCD display.

To convert the power in your 01, you need to address three areas:
1. Changing a connection on the power transformer primary winding.
2. Changing four fuses.
3. How to physically plug your 01 into a different wall socket.

If you need help on how to get inside your 01, check the disassembly instructions page.

Transformer Connections

Common
240V
230V
220V
117V
100V

The schematics show connections to Common and 100V. This may be the connection for Japan (even though the schematics are in English). I suspect the US connection is to 117V. (If anyone can verify this for the US or any other country, e-mail me and I'll enter the information here.)

Korg seems to have identified the following voltages with the following countries:

The circuit shows the transformer has two secondaries, one center-tapped, the other not. The secondaries are connected to the circuit board with a cable that has a 5-pin connector called CN21A. The pins are:

Unfortunately, the schematics do not show what these voltages should be. (If anyone measures them, e-mail me and I'll enter them on this page.) Here's a circuit description:

The center-tapped secondary feeds a full-wave bridge rectifier through connector CN21A. One output of the bridge is connected to a 7812, the other to a 7912. The center-tap is ground to the regulators.

The other secondary feeds a full-wave bridge rectifier. One bridge output connects to a +5-volt regulator (PQO5RF2). The outer output connects to system ground.

When you buy a fuse, you specify a current and a voltage. The voltage spec for a fuse is not necessarily the exact same voltage as what you find at the wall plug - it's a way of rating a fuse.

Power Cord