Static only on both AM & FM bands is usually the symptom of a poor/bad connection between your
radio and your antenna. Especially if substituting a different radio yields no improvement.
Here's some guidance from the Service Manual on troubleshooting this further:
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Note: The trick to the above is having a readily available 'test antenna'. Old guys normally have
an old freebie (liberated from a retired vehicle) stashed in the shop rafters for just these
troubleshooting occasions.
If you don't have one handy, either the treasure yard, ebay, or Amazon will have what you need --
with a little hunting you should be able to find something suitable that's also wallet-friendly.
Happy Hunting -- Let us know what you discover...