Call Uniden Parts.
Your email address may be getting SPAMMED??
But Uniden does need to do something with their communications, it really sucks overall.
Phones always busy, never answered or always in voice jail.
Reply via snail mail when provided with email addresses and phone numbers.
Phone and FAX numbers printed on boiler plate letters that are out of date or not working??
Come on, not that hard to sort this stuff out.
The 785D is still something they do repairs on, so they likely have some parts for these still otherwise ebay for parts units or search the web for parts units.
Might also try these guys as well??