Several problems can occur after longtime use of a record player turntable. Most are easy to diagnose and fix. To help you identify problems you probably can repair, here are tips.
Have you adjusted the parts to your player?
First, make sure all proper adjustments have been made on your turntable, starting with the tonearm.
Insert the headshell (the part to which the cartridge is attached) into the tonearm. It typically uses a bayonet pin-style locking mechanism. Insert the headshell, pin facing up, into the end of the tonearm. Holding the headshell in position with one hand, rotate the nut on the back of the tonearm until you see the headshell being drawn into the tonearm. Tighten until snug.
Phono cartridges are another common problem. If you hear a hum but otherwise are happy with the sound and want to keep it, you will have to adjust the location of the turntable and try to minimise the hum. A hum could come from power transformers in equipment, wiring in the walls or certain turntable drive motors.
There's an art to properly setting up a turntable. Many variables are involved, such as room acoustics, sound frequencies and vibration.
The cartridge is like a small microphone, and can sometimes pick up noise from the room. This can also create feedback when the cartridge picks up its own sound coming out of the speakers. If this happens, move your player farther from your speakers, or simply turn down the volume.
Is the problem external?
Your record player's parts can wear out over time, so it's possible you need some replacements. Contact the manufacturer and see what options are available for your model. You may be able to ship them your player to have it repaired, or they may at least be able to provide you with replacement parts.
If you end up repairing the player yourself, make sure you prepare for the job. You will have to be able to see small parts for this endeavour. A magnifying glass will help. If you've given the player a good once-over and are still unable to locate a problem, there is probably something wrong inside the player.
Is the problem internal?
When opening your player, be careful all attached parts or loose wires are clear and not under any physical stress. When looking inside for bad parts, notice burn spots and excess dust or dirt on electronic parts.
If your turntable runs on a belt system, make sure there are no incisions or breaks in any spots.
It's also possible that there's a problem with the circuitry on the inside of the player. If your player's circuitry is damaged, it may not be able to power on. Checking the power source on the inside for damage could save you lots of time while diagnosing. If the power source is beyond repair, replacing it may be your only option.
When soldering or electrical work is needed, be sure to ground yourself and be sure you are aware of how to use the tools required. Make sure you plug your player into an electrical socket that has ground leads. In the United States and Canada you can tell if your outlet has ground leads by looking for a three-pronged socket. European grounded outlets have two extra prongs.