Hello everyone, this is my first post. I have lurked forums for the past few weeks getting information here and there. But i haven't been able to find an answer to this besides something like a line filter. But its not really about just general noise picked up from the truck, theres very little to begin with. I have a few Cobra 29 lx's. One is stock, the one i'm working on WAS stock, and then i'm repairing another. This is a new hobby i've picked up so bear with me. Please, I'm just looking for advice. Not your opinions on whether or not i should be trying to mod my radio. Its fun to me and its already done. So...
I bought the radio in stock form and worked fine. I installed an IRF 529 mosfet kit and Hi-Fi receive kit. I installed the Hi-Fi kit first and it subdued the regular noise pretty well, but it seemed as though it had quieted everything a little more. I wasnt able to bring my cal meter up to where it needed to be either.
Then, I then installed the mosfet kit and it amplified everything to where when nobody was talking I would have to turn the volume down a LOT. But if i did that I could not hear anyone hardly. And if I turn it up, the amplified noise would completely drown out a weak signal, and most anyone talking I could barely hear. I can hear people but still the noise is way too loud. The best way to explain it I guess would be that I can hear people, but the noise overpowers 90% of them.
I've also just recently installed the schottky diode kit to try fix this but it hasn't helped.
What I've done
Mosfet Upgrade;
IRF520
R56 --> diode kit (1n914+470ohm resistor) diode towards front
C53 --> 3.3k resistor
C61 --> removed
C62 --> 100pf across it
R55 --> Removed and installed 22pf
C71 --> Removed and installed 82UF cap (polarity is correct)
C42 --> Removed and replaced with 2200UF cap (polarity is correct)
C59 --> 68pf installed on reverse side (had to increase power)
HiFi
C33 --> .1uF mylar
C40 --> .1uF mylar
C48 --> 1000uf electrolytic (polarity correct)
C39 --> 22uf electrolytic (polarity correct)
C37 --> .1uf mylar
C43 --> empty when i got my radio
C68 --> .33uf tantalum ( + towards right side of radio on component side)
C69 --> .1uf Mylar
C125 --> .001uF mylar
My question is would anyone know what I should look at to remedy this? I may just undo everything I've done and put it back to stock. But for now I will begin with removing the Hi-Fi kit.
Thanks and I look forward to hearing from y'all!
I bought the radio in stock form and worked fine. I installed an IRF 529 mosfet kit and Hi-Fi receive kit. I installed the Hi-Fi kit first and it subdued the regular noise pretty well, but it seemed as though it had quieted everything a little more. I wasnt able to bring my cal meter up to where it needed to be either.
Then, I then installed the mosfet kit and it amplified everything to where when nobody was talking I would have to turn the volume down a LOT. But if i did that I could not hear anyone hardly. And if I turn it up, the amplified noise would completely drown out a weak signal, and most anyone talking I could barely hear. I can hear people but still the noise is way too loud. The best way to explain it I guess would be that I can hear people, but the noise overpowers 90% of them.
I've also just recently installed the schottky diode kit to try fix this but it hasn't helped.
What I've done
Mosfet Upgrade;
IRF520
R56 --> diode kit (1n914+470ohm resistor) diode towards front
C53 --> 3.3k resistor
C61 --> removed
C62 --> 100pf across it
R55 --> Removed and installed 22pf
C71 --> Removed and installed 82UF cap (polarity is correct)
C42 --> Removed and replaced with 2200UF cap (polarity is correct)
C59 --> 68pf installed on reverse side (had to increase power)
HiFi
C33 --> .1uF mylar
C40 --> .1uF mylar
C48 --> 1000uf electrolytic (polarity correct)
C39 --> 22uf electrolytic (polarity correct)
C37 --> .1uf mylar
C43 --> empty when i got my radio
C68 --> .33uf tantalum ( + towards right side of radio on component side)
C69 --> .1uf Mylar
C125 --> .001uF mylar
My question is would anyone know what I should look at to remedy this? I may just undo everything I've done and put it back to stock. But for now I will begin with removing the Hi-Fi kit.
Thanks and I look forward to hearing from y'all!