Check the amps on the compressor by putting your meter in one of the wires that is going into your overload/relay it should read full charge
1.8 / 2.0 amps. if there is a leak in the system you should ready .5 or less than 1 amp.
Good Luck
Eddie.

low amperage means low refrigerant charge. u can add up by using a piercing valve wich will be the unexpensive way to go.

HI Richhappy . but aside from putting on the gauges is there a a accurate way to see if it any of these problems?

The Montreal protocol talks about release of ozone depleting freon like R11, R12, not R134A which does not harm the ozone layer. I don't think this applies to R134A which most fridgs use now.
A clogged capillary will show very low current, like .6 amp as the compressor is doing NO work, also, it will get rather hot and the condenser will be room temperature. A inneficient compressor will do some pumping of refrigerant and be warm and the condenser will be warm and the evaporator will be partially frozen but the freezer temp. will not be very cold, like 25- 30 degrees. Current draw, assuming 1/5 HP compressor, will be way below 1.4 amp.The high side pressure will be way below the "normal" pressure of 130-150 lbs gage.
A normally running compressor will burn the hand when you touch the high side tubing right at the compressor.
No energy is destroyed, so for a typical refrigerator with forced air evaporator and condenser, assuming equal surface area, the freezer is going down to zero degrees below ambient of 70 degrees. So for equal temperature differentials(equal energy transfer) the condenser must show a similar differential of about 70 degrees. Thus, the condenser should be 70 degrees above ambient, like 140 degrees.
A freon leak will show up as a partially frozen evaporator and the frozen part will be below zero. A combo of inneficient compressor and leak will show up as a partial frost pattern and the frozen part well above zero degrees.
If a refrigerator is sucking in air from a evaporator leak ( very common), the compressor will make noises as it is trying to compress non-compressables. The low side pressure will be higher than normal.
A frozen capillary, due to ice clog, can be verified by warming the capillary with a propane torch and looking for "normal" operation when thawed.
For the "modern" compressors, they will fail internally after trying to pump non-compressables for a period of time, like a week or two.
Correct me if I'm wrong, but the R12 replacement refrigerant R414B was developed to replace R12, the refrigerant that destroyes the ozone layer. The three refrigerants in R414B oxidize in the air and don't harm the ozone layer.
Soo.. it you have a system with R12 and a impossible to find leak, you could suck out all the R12, replace it with R414B and not be in violation of the protocol. Is this correct?
Location of leak.
For an evaporator leak, the compressor will make noises trying to compress the uncompressables and adding refrigerant will drive up the low side pressure with just a little refrigerant addition. The low side gage will show fluctuations from the passing of non-compressables or periodic pressure rises as the compressor periodically blows off high pressure to the low side.For a high side leak, addition of refrigerant will be sucked up quikly and the fridg. will get back to "normal" operation with the freezer getting down near or below zero degrees.
Hope this helps, please add comments/corrections.