Removed radio to find out whether antenna was disconnected. Now, radio doesn't turn on at all. What did I do?

you have a short disconnect the wiring and test motor

No function when pressing the buttons or TFT Screen Check whether the radio antenna is inserted or properly connected ,Wipe the disc with a dry soft cloth or replace a new disc

For detail, please see remote control dual describe. 5. MODE Button. Press it to select the mode: Radio, DISC (if there is a disc in unit), USB
Do not turn on or off the product in short intervals. ... IR remote control operation may be hindered by.

Replace the antenna assy

Doubt any dealer has one, going
back 7 years, let alone 21 years

Olds is out of business also

Salvage Yard or On Line or replace
with a non electric antenna

Some radios have a fuse inside them also.
I've found car radio's in general to be not so very good.
I'd not pitch it out until you can find someone reliable to test it.
Watch out though, some folks have a "vested interest".
That means they want to sell you a new one.
Be blessed.

2 ways you can do it> 1 find the fuse and pull it out but only if it is for the antenna or you can disconnect the antenna wire from the back of your radio, it is normaly a blue wire run with the power harness. Red is 12V. Black is Ground 0V. Yellow is Remote, it works with an AMP if you have one installed. Blue is normaly the power antenna. hope this helps> test it first by pulling the fuse to the radio and if the antenna does not operate then the power is from the radio

If you have a cigarette lighter check the fuse for it. Usually shared with the radio remote wire.

check that the antenna cable is still plugged into the back of the radio and plugged into the bottom of the antenna at the finder to check radio end insert 4 large paper clips into the square holes in the front corners of the stereo this disengages the lock mechanisms slide the radio out and check the connections if electrical antenna check the fuse on the back of the radio that it isn't blown if so replace. loosen the inner fender panel and see if cable still connected to antenna #2 check the fuse for the rear defroster its probably blown if so replace and check for any grounded out hot wires also check the connections at each end of the rear window sometimes they become corroded or unglued from the window, if any of the fine lines that cross the window have been scratched or removed partially this will also render the defroster inoperable

It sounds as if the antenna has become disconnected from the radio. You will have to pull the radio out of the dash and make sure the antenna is still connected there, then check and make sure it is still connected to at the fender well and in between.

pull out the radio or back up fuse ...in the underhood fuse box for a few minutes and retry the code....

Obviously if fuse panel has a power antennae fuse, simply pull it, otherwise you may have to get to connector at motor by removing part or all of sheild in wheel well to access it in some cases. Only other option would be to remove radio from dash & disconnect antennae power wire from radio. Don't forget you want it up before disconnecting if you can.