Teaberry Ranger T hiss crackle sound and squelch problem

[codecxbox]

Hello..
I recently got a Teaberry Ranger T..this radio had its final and driver missing and I installed the pair from a TRC451..
This radio is a charm receiving..it pickups signals where my SDR928 doesnt!
My problem is theres a low crackle and pop sound on CB and PA mode..I replaced several caps around the audio ic but its still the same..also if I turn squelch to around 9:00, there a loud rumbling static sound..if I continue to turn, that static goes away but squelch doesnt work, RX signals passes through..thank to another thread here, I found the schematic..so were should I troubleshoot first?

 

[Holydvr]

I had a popcorn crackle in a Cobra 138XLR and it turned out to be the audio IC itself. I recapped the radio first, but that did not help. Replacing the audio chip did the trick. Just my experience with that particular Cobra though.

 

[codecxbox]

replaced the TDA7502P and related caps, no change .what really worries me is the squelch problem..if I turn CW to around 1/4, a huge feedback squeal..if I continue, the squeal goes down, but still there and doesnt squelch RX noise..I removed a 373 transistor and that disabled squelch control, no squeal..