Best left to a trained person.
Check the web under "Air gun repair"
The Winchester model 353 was made by Diana airgun for various air gun companies from the late 1960's to 1973. It's rated at 378 FPS with a rifled barrel. To get it repaired I suggest the link below. Locate a air gun repair shop near you and have them repair it. There are air gun repair shops all over the country who make a living repairing and modifying air guns and rifles.
There are several shops around the country that make a living repairing older air guns. You can do a web search for "Air Gun Repair" or see the link below that list some shops.
I suggest you go online and do a search for "Air Gun repair" and select a shop where you can have it repaired. Or see the link below.
Depending on the model, There are shops around the country that repair air guns for a living. Do a search on the web for "Air gun Repair" and locate a shop near you to have it repaired.
See the link below for a list of air gun repair shops that maybe able to help you
can a air condition circuity board be repaired
There are many independent shops that repair older air rifles for a living. Do a web search for "air gun repair" and locate a shop near you to have it repaired or see the link below.
I suggest you search the web for "Airgun repair" and locate a shop near you to have it repaired or see the link below.
Not meant to be repaired by the user.
Take it to a gunsmith to be repaired.
Gun shop