Radio problem just has dashes on display-no sound-fuses look good changed batt

Do you have any dash lights on when you try to start is sound like a bad relay test your starter relay in your fuse panal

check the fuse under the dash .

Since your car was the one getting jumped there should be no damage,all I can think is if the batt. was flat dead it may have changed the settings on the body control computer,I would suggest
looking in the owners manual for dome light options ,I think the radio is the "remote control" for a lot of owner options like that.
Also make sure the chassis ground ( the smaller black wire on the neg.batt. terminal) is a good connection.

This is usually an internal failure with the head unit (the radio box in the dash) usually getting a new head unit will solve the issue, however it could be as simple as a broken or disconnected connector. Try getting to the back of your radio and inspect the connectors. Also try jiggling the wires to see if its a loose/sloppy connection. Either way, you're going to have to pull apart the dash. In some rare cases, the vehicle will have an external amplifier, if this amp popped a fuse or had some internal fault, that would cause the radio to show everything, but have no sound. Check you fuses first, especially anything related to "Audio", "Instrument", "Dash", or "Amp"

check body ground to batt negative ????

I believe there are multiple bulbs in each of the units, as they blow the unit dims, change the bulbs you should be good

check your fuse.

hi check the batt first to make sure it is charged. second check your ground cable. and third check the main ignition fuse under the hood. it will be a very high amp fuse.

sounds like you have burnt through the insulation of two or more cables and they are fused together in the loom .Start looking from radio back

The unit will have 2 fuses, or at least a second power supply that is generally connected to continuous power, best bet is straight from the +ve batt terminal. If this power supply has been disconnected or has a blown fuse, then you will also loose memory functions from you radio.

1. Check first under the bonnet for a memory backup fuse holder that has generally less than 1 amp fuse,
2. no luck, then about the rear of your fuse box for a fuse holder,
3. or worst, behind the unit up under the dash. The wire from the back of the stereo on Sonys is generally the RED one for memory backup

restoring this power supply to your stereo will then allow for all your presets to be retained in memory

Good luck, happy to talk to you more about the problem, a "FixYa" rating will help my profile

regards
Graeme