I have a proton 300 table radio and it has very poor reception.

Poor reception and low volume of any radio is mostly caused by poor aerial performance.

If the aerial has been eliminated, the unit is properly grounded, has a good current and voltage supply and the loudspeakers and wiring have all been tested and found to be ok then the fault must be inside the radio.

In lots of parts of the world the ambient temperatures in the height of summer and the depths of winter can be outside the operating temperature range of the radio. It is not wise to switch on when these conditions exist as delicate electronics are easily damaged, especially when condensation might have formed on internal circuit boards.
My father once switched on his car radio after the car had been parked in the sun and something inside failed instantly. The repair guy said it was a common problem.

One further thought. Is the alternator overcharging; producing an excessive voltage that could damage the radio or alternatively is a loose supply or ground connection causing a strong surge current and inducing an excessive voltage in a nearby inductance...

Pioneer is a first line brand and should provide you the best signal. If you had good reception previusly and with a new Pioneed unit it's poor, your new Pioneer is defective!. Take it back and demand your warranty, so they should change it or repair it so it should sound perfect. DON'T TRY TO "repair" IT Might lose warranty!

Sorry to say but the lens needs to be sent in for repair. To repair or replace the AF motor is usually around the $200.00 range. Do not try to fix it yourself.

for the poor reception have you plugged in the antenna wire into the radio

Pull radio and check antenna plug in rear of radio, They'll still pull AM with antenna unplugged

Most radio reception problems that occur only while the car is running are caused by damaged diodes in the alternator. It can be difficult to diagnose this since most dealers and repair shops will not disassemble the alternator to test the diodes. If you can find a shop that rebuilds alternators they can test for bad diodes and replace them if necessary. Hope this helps.

I have a Proton car but I have never heard of a Proton radio.

As a matter of general interest, the flywheel tuning system was used on early radios before the superheterodyne system brought us agc lines and such sophistications. Selecting another station was a noisy business and flywheel tuning allowed the dial to be traversed quickly with a flick of the wrist. Those flywheels were heavy and mounted in ball bearings...

The trouble with trying to obtain spare parts for radios is mostly you can't. The manufacturer uses mostly bought-in standard electronic and hardware components and makes as little as possible, apart from the cabinet, the circuit boards and a few other bits and pieces and then will assemble what is generally regarded as a consumable item. The manufacturer's interest fades quickly when the warranty expires. Whatever (few) parts remain will be priced not to sell in order to build in obsolescence.
It is mostly expected that minor repairs will be handled by local repairers using standard parts until it becomes uneconomic or obsolete.

It might be possible to locate another plastic "flywheel" but searching would be a mammoth task. The number might not be a part number, might have been made by anyone and Proton is such a popular brand, model, type a search would not be easy.
The best alternative is to repair the original, adapt something else to do the same job or have a replacement made or devise another method of doing the same job.

Good Luck!

It sounds like the tuner is out of alignment. A number of things can cause this kind of problem. However, a realignment is a very costly proposition, especially when considering the used value of the Proton 320. If you really like this radio, you might want to try buying a used example off of eBay. They come up very frequently. Only... be selective. Don't pick anything from a seller without a lot of good feedback. And don't overpay ($50 tops).

The tuning module within the radio is getween the base circuit card and the display. A shot of tuner cleaner into one of the ports will usually bring back the FM performace (I just got done diong my own). Also, it goes without saying that you need to make sure your radio still has its antenna wire and that the vacuum didn't eat it. If this is beyond your skill level, find a computer geek (there are few radio geeks any more). Commercial repair would cost more than the value of the radio.

Go to a radio shark or to a phone store and tell them u want the Reception Booster that goes inside ur battery pack and this should improve ur Signal. :)