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YRC1000 memory battery replacement

The YRC1000 stores data such as jobs and parameters in CMOS memory, which is backed up by a battery. When the battery gets weak, the pendant shows "Memory battery weak" (0790 MEMORY BATTERY WEAK in the alarm code list).

Where the battery is​

The battery is in the CPU unit inside the controller. It sits on the back of the robot I/F board (JANCD-AIF01), which is mounted together with the CPU board (JANCD-ACP01). There are two battery connectors, CN114 (right) and CN115 (left).

How long you have​

  • Replace the battery within 30 days of the message appearing.
  • Leave the breaker on until just before you start. The memory is also backed up by a super capacitor, which after 30 minutes of power can hold the data for about 16 hours at 25 °C. Even so, replace the battery as soon as possible after turning the breaker off.
  • Just in case, make a data backup (system backup) beforehand.

Replacement sequence​

  1. Turn off the power, wait at least 5 minutes, and confirm that the charge lamps (orange LEDs) on the converter and amplifier are off. This prevents electric shock from residual voltage in the capacitors.
  2. Disconnect the cables connected to the CPU unit and the robot I/F board (control communication CN111, control power input CN101, pendant LAN1 CN105, plus USB, RS-232C, LAN2/LAN3 and I/O I/F if options are fitted).
  3. Remove the two screws (top and bottom) holding the CPU board and pull the board out of the rack.
  4. Leave the old battery connected and connect the new battery to the free connector. At the first replacement, the old battery is on CN114 and CN115 is free. From the second replacement on, use whichever connector is free at the time.
  5. Then disconnect the old battery's connector and take the old battery out of its holder.
  6. Fit the new battery into the holder and check that its wires do not stick out beyond the board. If the board goes back into the rack with the wires sticking out, they can be caught by the backboard and broken.
  7. Slide the board straight in along the upper and lower rails on the left of the rack, and connect it to the backboard connector. If it catches, do not force it: pull it out and check the board.
  8. Tighten the top and bottom screws and reconnect every cable you removed.

Do not touch the board's components, patterns, card edge or connector contacts. If you do, wipe off any dirt with a clean cloth. The replacement battery may be from a different manufacturer than the original; either can be used.

How this differs from the alarm code list​

In the alarm code list (RE-CER-A600), the remedy for alarm 0790 says to "check CN110/BAT on the AIF01 board" and to "refer to section 5.1.1.1 of the YRC1000 maintenance manual (RE-CHO-A108)". This does not match the maintenance manual (RE-CHO-A114) on the following points:

ItemAlarm code list RE-CER-A600 (Rev. 14, March 2026)Maintenance manual RE-CHO-A114 (Rev. 29, July 2026)
ControllerYRC1000YRC1000
Battery locationAIF01 boardBack of the robot I/F board AIF01
Connector nameCN110/BATCN114 (and CN115)
ReferenceRE-CHO-A108, section 5.1.1.1Section 5.1.1.3 "Replacing the Battery"

Both manuals are for the YRC1000; this is not a difference between generations. Both also put the battery on the AIF01 board. However, the cited RE-CHO-A108 is the DX100 maintenance manual in the manual list, and in RE-CHO-A114, section 5.1.1.1 is "Replacing the CPU Board". The reference in the alarm code list therefore appears to be out of date (or simply wrong). The available documents do not explain the CN110 name.

This article follows the maintenance manual RE-CHO-A114, which is newer and describes the procedure in detail. On the actual equipment, confirm the connector number printed on the board.

Source: Based on YASKAWA manuals RE-CHO-A114 and RE-CER-A600.