General Assist Technical Reference
ARTC72LATU / ARTC90LATU Indoor PCB Software Update
Software identification, affected serial ranges and required action
A software revision was introduced for ARTC72LATU and ARTC90LATU indoor units to address an operational issue identified on earlier software versions. Units manufactured from the serial numbers listed below are fitted with the updated software.
Service note: For units produced before the listed serial numbers, confirm the indoor PCB software version before replacing components or carrying out further fault diagnosis.
Overview
The software update applies to the ARTC72LATU and ARTC90LATU indoor units. The revision was introduced following an operational issue that required further system analysis and a software improvement.
Applicable models and serial ranges
| Model | Updated software fitted from |
|---|---|
| ARTC90LATU | Serial T005237 and above |
| ARTC72LATU | Serial T006422 and above |
Units produced from these serial numbers onward are equipped with the revised software version.
Software identification
| Description | Before modification | After modification |
|---|---|---|
| Software ID | 9708460031 | 9708460048 |
| Software label | F01 | F02 |
If a red dot marking is present beside the IC on the control PCB, this indicates the software was rewritten at the factory.
How to confirm the software version
- Isolate power to the indoor unit before accessing the PCB.
- Visually inspect the indoor control PCB.
- Check the software number printed on the IC chip.
- Check whether the red dot marking is present beside the IC to identify a factory-updated board.
Action required
- For stock units produced before the serial numbers above, update the indoor PCB software to 9708460048 / F02.
- For field service replacements, ensure the replacement PCB is at the latest software revision.
- After replacement or software update, restore power and confirm normal operation.
Quick reference
| Item | Details |
|---|---|
| Affected models | ARTC72LATU / ARTC90LATU |
| Old software | 9708460031 / F01 |
| Updated software | 9708460048 / F02 |
| ARTC90LATU updated from | T005237 |
| ARTC72LATU updated from | T006422 |
Important: The source information supplied does not identify a specific error code, converter model, or detailed failure symptom. This article therefore does not attribute the software change to a fault condition beyond the operational issue described in the source.