...You're thinking automotive refrigeration. Most consumer-grade refrigerators are a sealed system that is literally welded shut everywhere; they cannot lose refrigerant unless there is a leak. Unless that leak is obviously caused by an accident like impact damage to a copper tube, the entire system is suspect as a corrosion victim and only a really expensive box is worth the cost of correctly doing a evap replacement (the most common leakage point) and recharge.
Consumer refrigerators have a lot of objectively hinky manufacturing in them; the prevalence of compression-coupled copper-to-aluminum joints is a real weak point service-wise. While it is much cheaper to crimp/swage the aluminum evap or the condenser tubes in a fridge directly to the copper compressor tubing from a manufacturing standpoint, it makes reliable repair very difficult. Replacement parts which have a copper stub to silver-solder (high temp; almost brazing) to are usually more expensive than you can sell all but the most expensive fridges for used once you factor in the cost of flushing and recharging the unit.
There are some expensive units that are based on commercial refrigeration; these are designed to be repaired and have fittings for your gauges built-in. But in general, if it doesn't have those fittings, it's really not meant to be repaired and you're fighting an uphill battle against corrosion leaks, clogged evaps, orifices and damaged compressors that are just hanging on by a thread. If there's a problem other than simple electrical, recycling the damned thing is better for your peace of mind and for the world as a whole. 
mnem
Our current fridge when brand spanking new froze down the condenser plate nicely but after a few months wouldn't so we rang our supplier..... a small mom&pop retailer and he took the thing away for investigations and left us with a loaner.
Drove him nuts but after almost disassembling it found the leak with his sniffer and rewelded the piping joint properly and recharged it with refrigerant. 25 yrs later it's still going strong. 
Mike was a damn fine appliance technician and keen duck shooter so we always had something to chat about .....crying shame the big stores ended up making his business unprofitable and he closed. 
Those older units had bigger compressors with a lot of refrigerant in them; they could easily frost up the back panel over the evaporator and were designed to work like that. The newer stuff has a compressor the size of a hamster with a thimbleful of refrigerant (only a slight exaggeration); they make their cold entirely by running the piss out of that little compressor and circulating lots of cold air through a very well-sealed and insulated tandem box.
If these frost up like that, it is muey gaucho; that means the evap is frozen over and there is no airflow. You get burger stuck to the back of the freezer and warm milk in the fridge.
*blerk*But those units do have good Ferengi potential; if the compressor tests good, usually it means the evap fan is seized up or the defroster thermal limit switch and/or timer have failed or if you're really lucky, the evap drain clogged up and that's what caused the evap to freeze. Fans are easily fixed with disassembly, cleaning and oiling the felt glands in the bushing caps. The thermal limit switch and timers are cheap, and often easily Macgyver-fied to use parts scavenged from units that died a grisly compressor death.
Wash the unit out with a garden hose, take all the shelves out and get to the evap chamber. Hose that and the defrost drain out, replace parts as needed, then wipe it all down with Clorox water.
Set in the back of the shop for a couple weeks burn-in & keep a log of temps 2x a day, then KA-CHING!It was when the asshole salesmen started trying to sell unrepaired and unvetted fridges and stoves... and started thinking they could give us orders... and the owner didn't back us techs up when we told him how dangerous that was... that I looked for work elsewhere. It
was a nice, decent-paying low-stress gig that fed a natural-born fixer's sense of self-worth. After that happened, it became just another shit-show.
When one of the salesmen (a right useless git in all aspects except that he could fill out a salespad for a product that sells itself) complained that his bonus was too small... and it was literally more than I made in a month... I told him he needed to shut the fuck up right then and there or he would find my foot on his throat.
When I left, they were expanding wildly... 4 stores around San Antonio and all moving new Ding & Dent appliances by the semi-load. Last time I looked in on them, they had only the original location and another on the South side selling only used, and that only 2-3 days a week.
mnem
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Topic: Test Equipment Anonymous (TEA) group therapy thread (Read 16710672 times)