Short answer: If your garage door opener is humming but the door won’t move, 9 times out of 10 it’s one of three things: a blown capacitor (~$165 to fix), a stripped nylon drive gear (~$185), or a broken spring causing the door to be too heavy to lift (which is a spring problem, not an opener problem — $189 fix).
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First, a 30-second diagnostic
Before calling anyone, try this. It costs nothing and tells you whether the problem is the opener or the door itself:
- Pull the red emergency release cord (it hangs from the opener trolley, inside the garage, near the ceiling).
- Lift the door by hand.
- Result A: door lifts easily and stays at chest height when you let go → opener problem.
- Result B: door is heavy, sticks, or slams down → spring or cable problem. The opener is humming because it’s trying to lift a door it physically can’t move.
If it’s Result B, stop using the opener. Every button press after this burns the motor or strips more gear teeth, turning a $189 fix into a $459 opener replacement. Call a pro.
If it’s an opener problem — the 3 usual suspects
1. Blown capacitor (~$165 to fix)
The motor capacitor provides the surge of power to start the motor. When it dies, the motor can still hum (power is getting to it) but can’t generate enough torque to turn the drive shaft. Symptoms:
- Steady humming sound, 10–15 seconds, then the opener stops itself
- No visible lights or movement
- Happens on both remote and wall button
- Opener is 5+ years old (capacitors wear out — this is normal)
Fix: swap the capacitor. Takes 20 minutes. $165 total including the part.
2. Stripped nylon drive gear (~$185 to fix)
Most chain-drive and screw-drive openers use a nylon main gear. Over 8–12 years, the teeth wear down and eventually strip. You’ll see:
- Humming that sounds more “whirring” or “grinding”
- Sometimes small plastic shavings on top of the opener housing
- Door opens partially (a few inches) then gives up, or doesn’t move at all
- Motor sounds like it’s spinning freely — it is, because the gear isn’t engaging
Fix: gear kit replacement. Brand-specific (LiftMaster, Chamberlain, Genie all use different kits). 45 minutes on-site. $185 total.
3. Logic-board failure ($230–$320)
Less common, but happens on openers approaching 12+ years or after a major power surge. Symptoms are erratic: opener randomly opens, fails to respond to one remote but works with another, or just goes dead. When the humming is accompanied by weird flashing LEDs on the opener head, this is usually it.
Fix: board swap. Needs the right replacement board for your model. $230–$320 including part.
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When to repair vs. replace the whole opener
Rule of thumb: if the repair costs more than 40% of a new opener, replace. A new DC belt-drive opener with smart/myQ, battery backup, and a 3-year warranty is $459 installed.
| Opener age | What to do |
|---|---|
| Under 8 years | Repair — you’ll get another 5+ years easy |
| 8–12 years | Repair if cost <$200, else consider new |
| 12+ years | Usually replace — motor is end-of-life anyway |
| 15+ years | Always replace — safety features have evolved |
Brands we fix
LiftMaster, Chamberlain, Craftsman, Genie, Sommer — we stock common parts for all five on every truck in San Antonio and Round Rock. Linear, Marantec, Guardian, Overhead Door, Wayne-Dalton — we can usually get parts same day or next day.
If your opener is an off-brand from a big-box store more than 15 years old, parts are usually the bottleneck — replacement is often the smarter call.
The $129 diagnostic — and why it’s waived
We charge a flat $129 to come out, test the opener, and tell you exactly what’s wrong. If you book the repair with us that same visit, we waive the $129 entirely — you pay only the flat-rate fix price ($165/$185/$230+). So a standard capacitor swap is $165 out the door. No trip charge, no surprise fees.
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Frequently asked questions
Can you come today?
Yes — 60–90 minute dispatch across San Antonio and Round Rock metros on weekdays. Emergencies (door stuck open, car trapped) get priority response 24/7.
Can I fix the capacitor myself?
Electrically, yes — but capacitors can hold a dangerous charge even when unplugged. They need to be discharged safely before handling. If you’re comfortable with electrical work and know how to discharge a capacitor, it’s a $15 part and 15 minutes. If you’re not, the $165 pro fix is cheaper than the hospital.
My opener works but makes weird noises. Separate issue?
Usually yes — most “weird noise” issues are dry rollers, loose hinges, or an unbalanced door pulling harder on the opener than it should. These show up in a 21-point tune-up ($89 flat) and usually add years of life to the opener.
More detail on our garage door opener repair page.