01/W Power

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rev: 08Nov21
Topics
Battery
  Changing the battery
  A00: Init Combi
AC Power
AC Power Overview
Changing Voltages for Foreign Countries
Transformer connections
Power Ratings
Fuses
  What's a fuse for?
Power cord

Battery

The Battery Everyone Has
There is a battery inside the 01 that is used to retain information while power is turned off. The 01/Wpro and proX use a type CR2032, a common battery that costs about US$3. I've seen them at Radio Shack [02Apr14].

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.

Changing The Battery

Don't forget to save any custom work to disk (or an external MIDI device) before opening your 01 - you should be able to re-load everything after you replace the battery. Factory Progs and Combis are stored in ROM and need not be saved.

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]

2: Ed Edwards reported how he found 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]
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A00: Init Combi
If you see the Combi "A00: Init Combi", you need to load the factory Progs and Combis from ROM. This process is sometimes called Initializing or Resetting the 01. Click here to see instructions.

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.

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AC Power

- NOTICE -
I CANNOT ACCEPT ANY RESPONSIBILITY FOR THE ACCURACY OF THIS INFORMATION. THE USER ASSUMES ALL RISKS ASSOCIATED WITH THE USE OF THIS INFORMATION! 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!

AC Power Overview

The 01 takes AC power directly from the wall. It does NOT use a "wall wart" (a box/cube that plugs in the wall and has a dangling wire). Different countries have different mechanical plugs and sockets and internal connections.

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.
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Changing Voltages for Foreign Countries

Visitors to this section typically want to learn whether they can change their 01 to work with the power available in another country. Theoretically, you can. But I've never done it, and don't know anyone who has. All I can do is give you the information I have and wish you luck!

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

The schematics show a power transformer (Part #TC-046, Part Code 400012700) with six input taps:

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:

Code Country? Code Country? Code Country?
100JP Japan? 220GE ? 230SE ?
117EX ? 230GE ? 240AF ?
117CN Canada? 230FR France? 240AU Australia?
117US USA? 230WG West Germany? 240GE ?
230SC ? 240UK United Kingdom?

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:

CN21A-1: One end of the secondary with no center-tap.
CN21A-2: Other end of the secondary with no center-tap. Fuse FU4 is in this leg.
CN21A-3: One end of the secondary with a center-tap. Fuse FU3 is in this leg.
CN21A-4: Center-tap (system ground)
CN21A-5: Other end of the secondary with a center-tap. Fuse FU2 is in this leg.

Checking voltages
If you decide to try and change the primary tap and fuses (for travel to another country), it would be wise to unplug CN21A before turning it on the first time. Measure the AC voltages on the pins of CN21A to make sure they are correct before plugging it into the rest of the circuit.

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.

I've forgotten what you want the peak or RMS voltage to be at the secondary (break out the old textbooks) - probably about 2 volts (peak) higher than the regulator outputs (to cover the dropout voltage)
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Power Consumption (printed specification, not actual)
01R/W: 11 watts
01/W, fd, pro, proX: 20 watts
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Fuses
The schematics show four fuses in the power supply (see table).

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.

01/Wpro & proX Fuse Ratings
Location Label 100-120V 220-240V
Transformer Primary FU1 250V  800 ma 250V  T250 ma
+ 12 V regulator FU2 125V  1.6A 250V  T800 ma
- 12 V regulator FU3 125V  1.6A 250V  T800 ma
+ 5 V regulator FU4 125V  6.3A 250V  T3.15A
 
What's a fuse for?
A fuse is a specially designed length of wire that melts when the power gets too high. Power is a combination of voltage and current (specifically, voltage times current) - the more power, the more heat. A circuit malfunction can cause too much current to flow. This increases the current (power) through the fuse, and it (hopefully) melts before a more expensive component does. It is very important to replace fuses with the same value the circuit was designed for.
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Power Cord

Wall sockets in different countries have different physical configurations. If it were me, I'd buy two power cords that mate with the 01 socket  in my native country (one cord as a spare, just in case) and take them with me. Once I got to the new country, I'd go to the local electrical store and buy two wall plugs. I'd cut the original plugs off the cords I brought and attach the new plugs.
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Copyright ©1998-2002, 2008 by Ken Westover at Cliff Canyon Publishing Co. All rights reserved.
This material may not be distributed without the written permission of the author.
E-mail questions or comments to cliffcan@indra.com.

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