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Cobra 142gtl
- Thread starter kaos513
- Start date
Are you sure it is installed so that the print is upside down when looking at it from the front of the radio?
Whoever said to throw it away is crazy it can be fixed... I have brought many a screwdrivered radio back to life..
Double and triple check all solder joints, make sure nothing is joined that shouldn't be. Check pin 8 for +8V and check pin 17 for +3.5-4.5V.
Also, is there a way you can take a good, clear, close-up picture of the whole board? I'd like to see if there's something visually amiss.
~Cheers~
Also, is there a way you can take a good, clear, close-up picture of the whole board? I'd like to see if there's something visually amiss.
~Cheers~
kaos, i think we are going to need some pics to make sure you have the PLL installed correctly.
take a pic of the component side of the board and the solder side of the board.
you installed the socket with the notch facing the opposite way than it should have been, but that doesnt really matter as long as the chip is put in correctly.
i only mention this in case you chose to line up the notches on the chip and socket.
i understand that you are wondering why the radio seemed to TX with no PLL chip, and now it does not.
the PLL chip is responsible for generating the frequencies that the radio operates on, and without it, the radio has no way of "making its own" transmit frequency in the CB band.
the fact that you are seeing the radio "key up" with no PLL chip in it leads me to believe that there is something more going on here.
you said that the radio had a freq counter connected to it at one time?
how did you discern this?
how exactly was this old freq counter connected to the radio?
do you have the freq counter?
it is possible that the chip you got from china is bad. do not install the other one until you have more of an idea what is going on.
you may blow it and be out of luck.
i do have to say, and i mean no offense by this, that you are probably in over your head with this radio.
PLL problems can be real pains in the ass for people that know what they are doing, and if you dont already know what you should be looking for, it will confuse the hell out of you.
if you want to get help here, you're going to need to make a couple of very detailed posts that include voltage measurements on each pin of the PLL, every part you have either removed or replaced in the radio, every detail of what you found in the radio when you got it, and as many pics of this chassis as you can muster.
you are also going to need to buy a freq counter. not the one with coax connectors on it, but one that has a BNC jack on the front.
you are going to need it to confirm that the problem does indeed lie in the PLL circuit and not in one such as an oscillator.
LC
take a pic of the component side of the board and the solder side of the board.
you installed the socket with the notch facing the opposite way than it should have been, but that doesnt really matter as long as the chip is put in correctly.
i only mention this in case you chose to line up the notches on the chip and socket.
i understand that you are wondering why the radio seemed to TX with no PLL chip, and now it does not.
the PLL chip is responsible for generating the frequencies that the radio operates on, and without it, the radio has no way of "making its own" transmit frequency in the CB band.
the fact that you are seeing the radio "key up" with no PLL chip in it leads me to believe that there is something more going on here.
you said that the radio had a freq counter connected to it at one time?
how did you discern this?
how exactly was this old freq counter connected to the radio?
do you have the freq counter?
it is possible that the chip you got from china is bad. do not install the other one until you have more of an idea what is going on.
you may blow it and be out of luck.
i do have to say, and i mean no offense by this, that you are probably in over your head with this radio.
PLL problems can be real pains in the ass for people that know what they are doing, and if you dont already know what you should be looking for, it will confuse the hell out of you.
if you want to get help here, you're going to need to make a couple of very detailed posts that include voltage measurements on each pin of the PLL, every part you have either removed or replaced in the radio, every detail of what you found in the radio when you got it, and as many pics of this chassis as you can muster.
you are also going to need to buy a freq counter. not the one with coax connectors on it, but one that has a BNC jack on the front.
you are going to need it to confirm that the problem does indeed lie in the PLL circuit and not in one such as an oscillator.
LC
i would really rather have them out here in the public domain so others can follow along and help.
you can upload the pics to this thread just like you can with your email account.
scroll down to where it says "additional options", and click "manage attachments".
this will bring up a window that will allow you to upload 5 or 6 pics from your computer.
just click "choose file", and you can upload them from wherever on your computer you have the pics saved.
i like to put them on my desktop first for easy access.
LC
you can upload the pics to this thread just like you can with your email account.
scroll down to where it says "additional options", and click "manage attachments".
this will bring up a window that will allow you to upload 5 or 6 pics from your computer.
just click "choose file", and you can upload them from wherever on your computer you have the pics saved.
i like to put them on my desktop first for easy access.
LC