Cobra 148 GTL help

[DX47]

Hello,

I just aquired a old 148 GTL from a cousin of mine. It was bought orginally in 1987. Apparently, when he was a teen, he messed around with the radio, trying to unlock the clarifier, and getting an additional upper and lower 40 channels. He did all of this years ago and can't remember exactly what he did.

The AMC limit transistor has been clipped, and for all I know the finals may be blown.

I have taken pictures of the board and a few areas that I am unsure of what the heck is going on.

Number one on the list, is what are these two Diodes? Are they supposed to be there? They had tape around them to keep them from shorting out the board.

 

[DX47]

Next up is two black wires going to the PLL

They go to the PLL from the CB/PA switch at the front of the rig.

 

[bushwacker]

The black wires running to the cb pa switch are for extra frequencies. It looks like he did a mod to control pin 10 of the pll for extra freqs. The diodes I'm not sure of.... if I had the radio in front of me I could tell you what they are for.... right now I have to look at the picture of the solder side of the board you posted and try to rememeber what exact section that is and what components are there and if any part of that circuit is modified.... my memory isn't that good. One thing I will say is you can tell if wasn't a tech that put those diodes in.... no tech would leave those leads so long.

I'm thinking he could have tried to open up the clarifier and removed switching diode (s)... its possible he put the diodes back in..... but again, by looking at the solder side of the board and going by memory, I can't tell exact what circuit has had the work done to it. My memory isn't that good.

Your radio has extra channels in it.... by flipping the cb /pa switch you are changing the state of pin 10 on the pll. Doing this will give you the regular cb band with the switch one way..... and with the switch another way it will give you another bank of channels that will most likly be above channel 40.

If you want to see what mods are done.... check out the radio. Check the output power ( carrier high or low?), check the voltage going to the final ( stock is 8 volts). Check out if the tx freq moves when the clarifier is adjusted... check out what freqs you get when the switch is flipped.
A frequency counter is helpful as well as a watt meter.

Sounds like its still a useable radio. Its pretty much all I can tell you without having the radio in my hands and flipping it around a few times.

Take care