Hill Country Solar Solutions does HVAC work. I have not needed a repair on my system, but this company fit my windows for solar screens and did a great job. They are decent, reliable people. Contact Brad Adams at (512) 576-0947.
I walked into a hot house last night and ended up using Stan's Heating & Air Conditioning Inc. (512) 929-9393. Called around 9:30am on a Sunday morning, they had a technician out by 11am.
It turns out that the 24V transformer for the control panel had blown (possibly due to a power surge), some of the cable ties were actually molten. Luckily, the A/C's circuit board was still OK. The technician seemed to have no trouble diagnosing and fixing this, he was done by noon.