When I moved out of my apartment in California, the landlord and I agreed to have a walkthrough at 5pm on the day of my moving out-- this is also the time by which the landlord needed me to be out of the apartment. The landlord had a quick look around, said everything looked good and took the keys from me before I left. My understanding was that the apartment was in fine condition and that I would be refunded my full security deposit. When I received the returned security deposit, I found that he landlord had deducted more than half of the deposit for painting, cleaning and replacing window blinds.

My reading online suggests that the landlord was obligated to give me a list of deficiencies during our walkthrough, theoretically so I could have a chance to repair those problems before moving out. Since this inspection did not happen until the last possible minute, I would not have had time to repair anything, but I thought that I would still be told about the repairs needed on the apartment.

Was the landlord obligated to tell me about the repairs that I would be billed for? Is a small claims court likely to order the landlord to refund my deposit?

Yes he is suppose to give you a detailed itemized letter showing the deductions.
It sounds like he may be using your deposit for fixing normal wear and tear which most likely shouldn't be deducted from your deposit but if you didn't take pictures or don't have proof on how you left the place it may be too hard to prove.
I would start by telling him you want a letter of itemized deductions first and then take it from there.

Thanks, N0help4u!

I've got an itemized list of deductions already and am waiting for receipts to back up those deductions. The list shows the amounts for the various deductions, but I only received it with the partial deposit refund check rather than during the inspection.

I'm wondering if the landlord's failure to tell me about any possible deductions during our inspection disqualifies him from making any deductions later, as he did in this case. I was completely moved out during the inspection and turned over the keys at that time, so there could be no existing damage caused by me that was not visible during the first inspection.

Yeah the receipts are what you need.f
I am not sure if he can go back over and change his mind claiming he' didn't notice' when you did the walk through but I would get the receipts and then challenge him to explain how it is that you owe for it.