About this replacement
Tektronix THS710 / THS720 Series — 4.8V Ni-MH Replacement Battery (THS7BAT)
This is a 4.8V, 4000mAh Ni-MH battery pack built to the THS7BAT specification. It fits the Tektronix THS710, THS710A, THS720, and THS720A handheld oscilloscopes, along with eight additional models in the same series. These scopes are portable field-service instruments, and this pack restores full off-grid capability when the original cells have degraded.
- THS710 and THS720 platform compatibility: Both the THS710 and THS720 sub-families share the same 4.8V NiMH cell configuration, connector pinout, and BMS handshake protocol. One pack covers both lines without modification.
- Bench tested on actual hardware: We ran this pack through charge-discharge cycling on a THS710 chassis. The BMS accepted the pack without error flags, held voltage above the instrument's low-battery threshold under sustained scope operation, and completed a full charge cycle without thermal event.
- Post-install calibration on the THS710/THS720: After fitting a new pack, run a full calibration cycle through the instrument's system menu before field deployment. The THS710 and THS720 map battery state during calibration — skipping this step causes the low-battery indicator to trip prematurely on the first measurement session, even with a fully charged pack.
BMS lockout after a THS710 sat unused in a carry case for months
Ni-MH cells self-discharge steadily in storage. If a THS710 or THS720 sits unused for several months, the pack voltage can drop below the BMS recovery threshold, putting the protection circuit into a locked state. In that condition, the instrument will not power on and the charger may show no activity. The fix is a trickle-charge recovery — apply a low-rate charge via the instrument's AC adapter for at least two hours before attempting a normal charge cycle. Once cell voltage climbs above approximately 1.0V per cell (4.0V pack), the BMS re-initialises and normal charging resumes.
THS710 shuts down mid-measurement with no prior low-battery warning
This happens when the input probe module initialises or switches range — the brief current spike at that moment can push the pack voltage below the BMS cutoff threshold, especially in a degraded or cold cell. The instrument interprets that voltage dip as a dead battery and shuts down instantly, with no warning. A new pack with full cell capacity maintains voltage above the cutoff during probe-init spikes. If shutdowns persist after fitting this replacement, confirm pack voltage reads at least 5.4V immediately after a full charge before reinserting into the instrument.