Sound has become muffled when switched on, then radio clears. Sounds like tuner.

I will try to replace the main board first.

Sounds like Tuner AGC voltage problem. If this voltage related to its tuner is abnormal, this kind of fault can occur. Contact any service technician. http://electronicshelponline.blogspot.com/

hello depending on what sort of transmissions you are listening to all should be set to NFM ,cb radio will be set at AM ,radio stations WFM so check the mode you are using this could be your problem

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).

If the sound is coming out clearly with the radio on, then there is a problem with the cd drive or its connections. If your stereo has aux. inputs, you could run an mp3 player until your ready to replace it.

If you need further help, reach me via phone at https://www.6ya.com/expert/david_f2436a37cbb50365

Hello,
Please download Instruction Manual of DAV-DZ260 from Sony Support and go to page 25 and select appropriate sound option.
The disc in player doesn't match with current sound selection thats why you hear muffled sound.
Thank you.

Hello dan5260,

Your audio processor might be going bad or at least one of the capacitors might had malfunctioned.
We are actually not talking about much expense in fixing this problem. At my shop here how the pricing would go:

Parts: $20.00-$30.00
Labor: $60.00 per hour (1 hour limit) Total $120.00
Starter Fee: $30.00

So total will be about $170.00 - $180.00

This is just an estimate based on my shop, your local shop might charge more or less.

I hope this helps,

Thank you,

Shuttle83

sounds like poor solder on the ground conections of the tuner, depending on the age of the TV frostman

check to see if the radio is clear. If it is it may be the signal going into the amplifier. if it is muffled as well, depending if you have an Equalizer hooked to the unit. This also could cause the problem. Finally check the bass, treble balance and volume knob but turn them back and forth while unit is on and see if signal clears up momentarily. if this is the case the control knobs need to be cleaned. Also spin the connection jacks {RCAs} in the rear and see if this clears it up. If not you may have to have the unit serviced by a professional.