[masraum]

Originally Posted by cabmando

The humming or buzzing is most likely your contactor where your main power attaches at the unit. As for the compressor and fan not running, it could be the cooling contactor inside the unit or the capacitor. If the capacitor is one of the round or oval metal type, look for any deformity in the housing. Normally they will have some sort of bulge in them when they go bad. BE CAREFUL when you install the new capacitor.

Something you checked was power. Did you physically close the contacts on the contactor? That buzzing could mean the contacts didn't fully close and you weren't getting power to the fan and compressor. Take an insulated screwdriver and in the center of the contactor you should see a small bar with a spring, press that bar in and it will close the contacts.

Thanks, yes, Bill (futuresoptions) thought the same about the contactor (why don't they just call it a relay?). I sent him some pics and the contacts looked like an old set of points (but bigger). He had me try sanding those a bit to see if that would help. Last night while I was troubleshooting, I checked the voltage on both sides of the contactor and with the AC in the "on" position, I did have 240V on both sets of terminals. I also tried what you mentioned by pushing the bar in and it seemed to make no difference

I didn't see a bulge in the capacitor, it was one of the cylindrical models with the fan and compressor capacitor built into one unit. Last night I put a multimeter on it and did not get 35uf and 5uf on herm and fan which I thought was a pretty good indication of failure. This morning when I pulled the capacitor, I noticed that the top was bulging some, but since the top was supposed to be domed anyway, it wasn't very obvious in the dark when I looked last night.

Originally Posted by red-beard

Johnson supply. They are everywhere. Get the model of the part and/or the AC unit.

Yep, that's where I ended up. I'm glad that they sell to the public, the first place I tried did not.

Originally Posted by red-beard

And if you were closer, I'd loan you a portable unit, I have 4 for cooling my assembly area at my business.

Thanks, Red! Yeah, I didn't even think about a window unit last night, and we've got a 24hr Walmart less than a mile away. It's funny, last night our low was 77 (stayed 80-82 in the house). But the night before last it got down to 67. Why didn't the damn thing break Tuesday instead!

Originally Posted by billybek

Could be the capacitor.
The start capacitor typically is round and the run capacitor is oval in shape although there are some out there that have both in the same housing.
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Check the condition of all the wiring connections (burnt/hot looking).

Thanks all for all of the help and advice. I found a local place that sold to the public this morning and replaced the capacitor ($34), and we are back up and running. I was going to replace the contactor anyway, but we aren't planning to be in the house much longer and it's still working so I decided to skip it for now. It's still a little warm in the house, but the temp is coming down. It feels much better than it did earlier this morning.