NEED TO KNOW THE AGE OF MY GE FRIDGE TBX23ZH - GE Refrigerators

well for 42 years its done good. it's more than likely the gas needs replacing if the motor is still working, surprising to see one still going this long.

Only when defrost cycle kicks in? Age of fridge?

You posted under a heading of a GE refrigerator. If it is, try this to find age: http://www.geappliances.com/service_and_support/faqs/

If not a GE product, check the manufacturer's web site for similar info.

Try to find out if the noise is inside or outside (under the bottom). If the noise is Inside, that will be the main cooling fan. Could be from hitting ice or a wire, or age meaning it needs replacing. If hitting ice or a wire will need to be cleared by accessing the evaporator section in the freezer. If under the fridge. pull it away from the wall and remove the back cover (screws) use a vacuum if needed an clean the fan blades, (unplug it first). It may still be due to the age, in which case will need to be replaced.

I would replace the defrost timer.

Can't tell the age without the serial number, but it is a 21 cubic foot refrigerator. Plug it in, if it cools could be a good garage fridge.

Generaly the control board controls everything sometimes you have a bad thermister GE has a help line I beleive it costs 20.00 bucks but you will need a meter and know how to use it and they willl talk you thru the repair .

It won't get cold in ref. because its not defrosting. Remove back wall of freezer and remove frost with hair dryer. This will get you a few days. Let me know the Brand, Model number and approximate age of unit.