Help me troubleshoot this Dixie Narco?

[SilverDuck]

I have a Dixie Narco machine with a model 300 refrigeration deck.  It does not cool.  All the fans run fine, the compressor seems to be doing it's job, but the evaporator is not getting cold.  The copper tube going into the evaporator gets iced up quickly, but the evaporator stays room temp.  The thermostat seems to be working.  The heat exchanger bulb does not get the least bit cold.

What would cause this?

[johnieG]

Low charge of refrigerant.

[SilverDuck]

So, I assume I have a leak somewhere?  Will this thing be cheaper to have fixed, or to pick up a refurb refer deck?  Vending world sells refurbs for $280 shipped.   Being that my unit is an R12 unit, won't it be expensive to repair?

EDIT:  Had the refrigeration guy here, he put on his gauges, and I am out of refrigerant.  He wanted $150 to test for leaks, and additional for 409a gas.  I told him VendingWorld has charged refurb units for $280 delivered.  He suggested I go that route, as I would have $200 in getting my unit recharged, and I am still dealing with an unknown compressor.

Another refer tech called, and is willing to recharge it with dye, not spend much labor time looking for leaks, and charge me around $70.  He said if/when it leaks back out, the dye will tell him where the leak is.

I am leaning towards the $70 repair, and if it leaks back out this summer, buy a refurb unit from Vending World.

Am I making the right choice?

[dr galaga]

Sounds like a good route to go. 

[Basementgeek]

R-12 is hard to find.  A 12 oz can could cost you $70.00.

I squirrelled some away just in case.

BG

[callmike2]

My experience is that it may have taken 30+ years for the refrigerant to leak out.  You still have a little or the tube wouldn't be frosting.  The compressor may not run long on empty. It needs the refrigerant moving through it to survive.  There must be a schrader valve on the suction line already if the guy put a gauge on it, so you could buy a legal R-12 substitute and replenish the refrigerant.  You can get it with the dye in it.  If you feel more comfortable having the other person do it, by all means that's the route to go.  Hope this fill-up takes 30 years to leak out also.