How do I to keep ale at cellar temperature?

I prefer drinking ales at so called cellar temperatures, between 50 and 55 deg. My ale keg is currently in my basement which is at 65 -68 deg. I have a fridge in the basement that I use for chilled beer and that is about 38 deg. So my problem is how can I keep my ale keg at cellar temperature without purchasing/acquiring another fridge. I have searched the archives and not found any threads relating to this, so any suggestions would be a great help.

Get an external temperature controller for your fridge. The e-bay unit can be built for ~$30 if you have any DIY skills at all. Set the controller to 5-8 degrees colder than your desired serving temp.

I'd keep it in the 38 degree fridge and just wait a couple minutes before drinking. It's really the only practical solution unless you want to warm up the fridge.

I have a conditioning cabinet attached to the keggerator by two air tubes. It maintains 50-55F. Two of the beer lines go into the cabinet and two are in the kegger. The photo shows the arrangement. The fans are plugged into the same power bar (controller) as the kegger, so air moves whenever the compressor is on. Major downside is water collecting in the kegger, so I have the drain open and it sits in a plastic tray.

Thanks. I will probably take the low tech method for now by waiting a few minutes before drinking my ale, and look into alternative methods in the future.