User question
One side is not working, example when put into the case, the sid that isnt working doesnt show the battery percentage
Artificial Intelligence Response
Direct answer to the question
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The earbud that doesn’t show a battery percentage in the case is almost certainly not making proper electrical contact with the case, is deeply discharged, or is desynchronized from the other earbud. Start with cleaning and seating checks, then perform the model‑specific reset (triple‑tap both touchpads while they’re in the case), and finally try a prolonged charge. If the problem follows the earbud (not the case slot) after cross‑testing, the earbud’s battery or charging circuit is likely faulty.
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Key points:
- Clean contacts on earbud and case; verify pogo pins spring freely.
- Make sure the earbud sits fully down (remove eartip and re‑seat).
- Fully charge the case; then deep‑charge the bad earbud 2–4 hours.
- Do a full reset and re‑pair.
- Cross‑test earbud/slot to localize the fault.
Detailed problem analysis
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Why the percentage doesn’t appear
- The F9 case only shows per‑earbud percentage when it senses charging/communication through the two gold contacts. Any contamination, misalignment, stuck pogo pin, or a battery that is below its protection threshold will look like “no earbud present,” so no percentage is shown.
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Mechanical/contact causes (most common)
1) Dirty or oxidized contacts:
- Clean both gold pads on the earbud and the two spring‑loaded pins in the case with 90%+ isopropyl alcohol using a cotton swab; let dry 1 minute.
2) Earbud not seating fully:
- Remove the silicone eartip on the problem side and insert the bare earbud; ensure magnets pull it down firmly and the lid closes without resistance.
- Press‑and‑wiggle test: with the earbud in, gently press it down and wiggle. If the display/LED flickers or the percentage momentarily appears, you have a seating/contact issue (try smaller eartips or clean again).
3) Stuck/broken pogo pin in the case:
- Lightly press each gold pin with a wooden toothpick; both must spring back equally. If one is stuck low, the case slot is faulty.
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Electrical causes
1) Deeply discharged earbud cell:
- With the case connected to wall power, leave the problem earbud in the case for 2–4 hours even if no percentage appears initially. Many cells need a pre‑charge before LEDs/percentages wake up.
- “Wake” method: remove/reinsert the earbud several times over 1–2 minutes; this can help the charger IC re‑negotiate pre‑charge.
2) Low case battery:
- Charge the case to ≥50% before testing; many cases limit earbud charge current when they are low.
3) Case slot vs earbud isolation:
- Cross‑test: put the working earbud in the “bad” slot and the bad earbud in the “good” slot.
- If the slot never shows percentage with either earbud → case slot problem.
- If the problem follows the earbud regardless of slot → earbud battery/charging PCB fault.
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Firmware/pairing causes
- Desynchronization between L/R can make one side appear offline even if it has charge. Do a full reset:
- On most F9 variants: place both earbuds in the case, keep the lid open, then triple‑tap both touchpads at the same time. You should see both earbuds flash twice; close the lid for ~10 seconds.
- “Forget” the earbuds on the phone’s Bluetooth list, then open the lid, remove both earbuds together, let them pair to each other (one will become “master”), and reconnect to the phone.
- Alternative reset (for buttoned variants): with earbuds out and powered off, press‑and‑hold both buttons 15–20 seconds until the LEDs cycle, then return them to the case for 10 seconds and re‑pair.
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Less common hardware faults
- Earbud Li‑Po cell aged or open‑circuit lead: earbud may play briefly but never shows charge/percentage. Replacement requires micro‑soldering a 3.7 V, ~30–50 mAh cell—often not economical versus replacement.
- Case charging rail or sense line failure on one slot: multimeter across the two pogo pins (carefully, lid open) should show a few volts when the slot is “active.” No voltage on one slot with a known‑good earbud inserted indicates a case fault.
Current information and trends
- F9 is a generic platform with many board/firmware variants; reset gestures and LED patterns differ slightly by batch. The triple‑tap‑both‑sides‑in‑case reset is the most common across recent F9 variants.
- Stuck or fatigued pogo pins and marginal seating due to oversized eartips are frequent field failures.
- Given current pricing of F9‑class buds, single‑earbud or full‑set replacement is often cheaper than battery/PCB repair.
Supporting explanations and details
- How the case “knows” to show a percentage:
- The case MCU looks for a load and/or a sense pin state when an earbud makes contact; only then does it attempt to read/report charge state or at least display that the earbud is charging. No contact → no display.
- Why deep discharge hides the indicator:
- The earbud’s battery protection IC opens when cell voltage falls too low. The charger inside the earbud enters a pre‑charge regime at a very low current; indicators often remain off until the cell reaches a safe threshold.
Ethical and legal aspects
- Safety: Do not puncture, bend, or short Li‑Po cells. If opening the earbud, disconnect the cell first and avoid heat on the pouch.
- Warranty and right‑to‑repair: Opening the case/earbud typically voids warranty. Consider warranty claim or seller replacement if the unit is new.
- E‑waste: If replacing, recycle the old set through an electronics recycler to avoid improper Li‑ion disposal.
Practical guidelines
- Quick checklist to run now (5–10 minutes):
1) Clean pads/pins with IPA; remove the eartip and re‑seat the earbud; press‑and‑wiggle test.
2) Fully charge the case; then insert only the bad earbud and close the lid for 30 minutes.
3) Do the F9 reset (triple‑tap both touchpads while in the case), then forget and re‑pair on the phone.
4) Cross‑test earbud vs slot to localize the fault.
- If localized to the earbud:
- Try a 2–4 hour deep charge with the case plugged in.
- If still no detection or percentage, the earbud battery/charging board is likely defective → replace the earbud or the set.
- If localized to the case slot:
- Inspect/unstick pogo pin; if mechanically damaged, replace the case or the entire set.
Possible disclaimers or additional notes
- Some online guides mention companion apps/firmware updates for F9. Most F9 variants do not support official firmware updates or a vendor app; treat such advice skeptically.
- LED colors/patterns vary by batch; rely on the reset gestures and pairing behavior rather than exact colors.
Suggestions for further research
- Look up your exact F9 variant’s quick‑start sheet for its reset gesture and LED meanings (often printed on the inner lid or small leaflet).
- If you’re comfortable with tools, search for pogo pin replacement or earbud battery replacement for “TWS F9” to see teardown photos matching your variant.
- Provide these details if you want targeted next steps:
- Age of the earbuds, any water/sweat exposure, and the exact LED behavior when inserting the bad earbud.
- Whether the problem follows the earbud or stays with the case slot after cross‑test.
Brief summary
- Most likely, the earbud isn’t making electrical contact with the case or is deeply discharged. Clean the contacts, verify pin spring action, ensure full seating (try without eartip), fully charge the case, deep‑charge the bad earbud, perform the F9 reset (triple‑tap both sides in the case), and re‑pair. Cross‑test earbud/slot to isolate the fault. If the problem follows the earbud after these steps, it’s a hardware issue—replacement is typically more practical than repair.
Disclaimer: The responses provided by artificial intelligence (language model) may be inaccurate and misleading. Elektroda is not responsible for the accuracy, reliability, or completeness of the presented information. All responses should be verified by the user.
