H3+

1. Make sure the patient is safe — swap in a backup unit if you need to.
2. Reproduce the complaint yourself and write down exactly what you see (screen, alarm, code).
3. Check power, battery, cables, accessories, and settings before ordering parts.
4. Then open the service manual above and follow its troubleshooting section.

Low battery icon source ↗

• Replace with a fully charged battery

ID field blank before recording source ↗

• No patient ID loaded: prepare the recorder again from the Holter software

Reverse-colour display (white on dark) and won't start a new recording source ↗

• The recording is complete; download it, then erase memory before the next hookup

Wrong cable message source ↗

• A 2-channel cable is connected: fit the 3-channel patient cable

RA / LA / LL / V lead fail at hookup, or lead fail during recording source ↗

• Reattach the named lead wire or replace its electrode; multiple leads: check all wires and the cable-to-recorder connection

Intermittent problems / complaint investigation source ↗

• V3.0.0+: copy DEVICE.LOG and RECORD.LOG via Windows Explorer before erasing; RECORD.LOG shows hourly battery voltage and lead-fail times
• Send them to Welch Allyn/Baxter tech support; the S/N and REF are under the battery

Leads off / bad waveform source ↗

• Swap patient cable, then harness, then ECG board

Power/battery source ↗

• Check AC fuses; fewer than 10 reports per charge = replace battery