Sooo our a/c just quit...
 

...working and it's 94* outside and 85* inside.
There's a humming sound out at the condenser outside that sounds like the motor is trying to start but can't. We just had the system serviced back in January, all was good, even after 10 years without a service call. I can spin the fan with a screw driver thru the protection screen so the motor isn't seized up. It was working fine this morning, or so I thought.
This will be interesting...

So, the fan is not running, and neither is the compressor. It is most likely the capacitor.

That's what I'm thinking but I'm no expert and I didn't sleep at the Holiday Inn last night either so I'm waiting to hear from the 'guys' that looked at it last.

Run capacitor

That's my thought, capacitor. The motor needs a jolt to start and then will run on regular power. A capacitor provides the jolt, unless/until it goes bad.

LOL. I'm not an expert either...but fix six or seven a year. Simple compared to even the easiest problem on a 911.

Usually the cap, but recently had a bad contactor (just a big relay) ...but can't be sure without testing. Also had a bad compressor on one and had a pro replace it.

Good luck...too hot for bad A/C.

And just in case... the $340 portable unit that Lowes sells isn't bad, seal off a smaller area (large bedroom etc) and it does the job. Had AC go out 2 weeks ago in similar conditions and the redheaded wife is going thru menopause. Literal life saver.

I sometimes work on tube amplifiers and those capacitors are perhaps a very different animal, but you do have to be VERY careful around tube amps because those capacitors can store lethal voltages. One of my amps has a circuit using several capacitors and operating at just under 600 Volts. I'd be comfortable swapping out a heat pump capacitor, but I would use a procedure that assumes the worst. I would NOT go anywhere near the guts of a microwave oven. FWIW.

Turn off power

Short across cap leads with screwdriver that has insulated handle

read capacitance value and voltage rating off fan cap or dual cap (if its the same one for compressor), dual cap will (obviously) have 2 pairs of ratings

order like part off amazon for 10-20$ (voltage rating can be higher)

82.5% chance that fixes the problem without a 200% service call, you may be able to source the cap locally at an ac supply store. Hopless despot and similar places don't seem to stock them in my area I think for legal reasons

My fear of electricity far out weighs my desire to be cool or to escape the wrath of my wife for it not working. Trust me on that.

I've posted this before.

You can use a portable AC, as mentioned by id10t, above.

Or.....I have a standard window unit that can be used in situations like this. It's only 5K BTU, but that's more than enough to maintain enough comfort to allow some flexibility on repairs to the main unit.

They are 110v, under $200, and well worth it.

I'll just put a block of ice in a pan and set in front of the fan my wife has constantly blowing in the family room. That should do just as well and be a lot cheaper too.

Our capacitor was replaced about a year and a half ago. I’m tempted to see what size/make it is and have one on standby.

Mine went out Saturday morning with symptoms the same as yours. It was bad capacitor.

My biggest concern was finding a place that would sell one to me NOW. I got that arranged through a master electrician 200 miles away.. Took longer to get the part than to fix it.

If you are fixing it yourself, look at the microfared numbers on the capacitor. Yours may be a dual capacitor like mine, which is the compressor (Herm) and fan. Mine was 40+5 440v.

Easy job, just don't forget kill the power to the unit (condenser) and then discharge the capacitor first.

Amazon sells capacitors, but I couldn't wait until Monday.

I wouldn't even know where to begin looking for a capacitor on the unit much less be able to get in a position to take it out. I'm old and don't bend like I used to.

It's a good idea to have a spare on hand.

I thought the same. Mine was three 1/4 inch machine screws for the cover, 1 screw for the capacitor retaining band. Then it was just 4 wire connectors, two for common, 1 herm, 1 fan.

Give it a shot!

I'll watch real close when they come to fix it and maybe do it next time, if I live that long.

I'm assuming your process is correct, but rather than ordering from Amazon, I would find a local shop where you can buy one. I've bought at least one or maybe two in the past, and was able to source them locally, usually in 30-60 mins once I'd determined what the problem is. Find a couple/few HVAC parts places, call around, "do you have capacitors? Do you sell to someone that's not a contractor?" And yeah, they are usually super cheap.

I stock the capacitors and motor contractors for all my AC units.