Noisy Compressor - Dixie-Narco DNCB 180/105-5

[myonlymachine]

Hello World!

This is my first post on the forum, very happy to be here. I recently acquired my first machine, a Dixie-Narco DNCB 180/105-5.
All the electronics work, it vends, drinks are cold, but I'm having one (maybe two) issues:

The compressor is very noisy:
https://vimeo.com/815669884
and also never* stops running. If I turn the thermostat to the "off" position, and then turn it back up to lets say 2, it will not immediately tun back on, but after getting going again, it will never stop running.

I have a couple theories as to what's going on here, but figured I would see what people here think first!

UPDATE: upon further inspection, I have a lot of frost on the (coil?) coming off the condenser 

[johnieG]

insofar as the frosting. make sure the evaporator (cooling coils) fan is circulating air, if it never shuts off either it never gets down to temperature due to lack of cooling capacity from the compressor, or perhaps a bad thermostat... The noisy compressor...depends on the noise, a rattling/knocking sound could be a worn piston or connecting rod slapping/knocking, or if it's only noisy upon startup/shut down then it could be a broken internal isolation spring...or even a copper line that has strayed too close to the compressor & is rattling against it... also check for a loose compressor fan blade or excessive play in & out ( laterally) on the fans motor shaft causing the fan blade to slap into the condensor/radiator coils, often times a noisy fan blade is mistaken for a compressor noise.        try this... turn off the machine, temporarily stuff a rag into the lower compressor fan blade so it cant turn, turn the machine back on & listen to see if that helps eliminate the noise or if it's really coming from the compressor itself.

[myonlymachine]

Thanks for the reply!
I have verified that the sound is in fact coming from inside the compressor…
From what I understand, there are no serviceable parts inside?
the drinks are quite cold, but I guess that just means the lowest setting is cold enough (if the thermostat isn’t also dead). Any advice for also troubleshooting the thermostat?

[johnieG]

the noisy compressor is a warning sign that it's going to fail internally, so don't be surprised when it does, & you are corrct, there's nothing to be done about it, it's a sealed unit, it will just need to be replaced when it does fail, if it doesn't drive you crazy in the meantime... the the thermostat could be tested by removing it from the machine using a continuity tester or an ohm meter, you'd used a cup of Ice water & see at which setting it will shut off at. but it's just quicker to replace it since you can't repair it either.

[myonlymachine]

I had to take a pause on the project, but I'm back at it.

So the compressor noise seems to go away intermittently when its tilted ~just~ right, which leads me to believe as you said its beginning to fail inside (maybe an unbalanced motor inside?)
 
The noise is intolerable so I'll need to work on it if I want to have it up and running. 

Also, there is in fact quite a lot of lateral play in the compressor fan, but I have verified this is not causing any of the noise.

I'm wondering if anyone has undergone attempting to replace just the compressor rather than the entire cooling deck? If so, 1-10 skill level required? I do a lot of repairs on my car, I'm comfortable with electricity, and I work with my hands for a living, but I've never worked with compressed gasses before.
Looking around, it seems like the going rate for a cooling deck is $300+ USD, and that's out of range for me right now.
Any thoughts would be greatly appreciated!

[johnieG]

Of course, I replace just the compressor(s) all the time when repairing or rebuilding refrigeration decks. very common & necessary if you want it to work!  also check for rotted or orn/dried up rubber isolation mounts (some people call them "feet") that help prevent vibrations & rattles generated from the compressor's mounting points to the deck itself. they shrink & dry up with age & are turned into ineffective shock absorbers.