Capillary tube vs TXV

Hello you all.
I'm having some problems with our " salad bar cooler", First it is not very cold and second the compressor make a agravating noise as a alarm buzzer.

I checked the pressures ~10 and ~190 psig at start up (the design pressures are according to the nameplate 140 and 235 psig). I tought the noise may come from a overloaded compressor,that somebody added gas in it, because the missing screws confirm than i am not the first one to look at it.
The condenser coil is not sparklingly clean but it seem OK to me. My concern is that the capillary tube might be blocked to produce that kind of pressure difference.

Because i never had a very good success or luck by replacing the tube, i am woundering if it can be replace with a txv "valve" as metering device instead?

I hope someone of you can help me on that.

Thank you any way

What refrigerant is used in the system.
A capillary is a fixed pressure drop control devise, high in = high out, a TXV is an thermostatically contolled flow regulator.
The buzzer noise from compressor is a problem, high star conditions labours the start. Overcharge would be my first guess, = high temps, high start torque conditions for compressor [the buzz ].
Recommend recovering the system refrigerant and recharge with fresh refrigerant at the rate perscribed on the nameplate.

Evacuate system, cut the capillary after the drier, look inside, look for blockage, use a file to cut and then break. If it's blocked, cut as much as you can before it goes up inside the case, if it looks clean, braze a length equal to the one cut out (or few inches shorter if it's a little clogged), replace drier, vacuum, charge system until equalized (through high side), run the fridge, if needed, add some more refrigerant. If you don't know how to extend a capillary tube...well, insert it into a small tube, 2 inches on both sides and braze it. You don't have to replace a cap tube all the way to the evaporator ( if its clean before). Hope it helps, I started on my own a long time ago and wish I knew a easy way for everything... Miss You Dad!!!!!!!

Hello Magoo

Yes, i forgot that, it run on 134a ( 11oz ), OK, the prescribed charge rate?? on the nameplate. I will have to look more for that.
I understand the capillary tube been a fix metering device and the TXV will vary according to suction pipe temperature. I know i'm wrong but it seem that the evaporator is never flooded enough.... Please excuse that one.
Any way i will try that within a day or so, and let you know.

Bye thank's

After you do what I suggested, blow the condenser, will prevent the problem...