I've been a CB hobbyist for a while now, but I've recently started to work on them since my local CB Technician past away. I've picked up and old cobra 2000 gtl it works just does not receive very well. Im planning on replacing the capacitors first, but when I opened it up some one has done some work to it looks like a mod but I'm not sure. Does any one know what has been done in the pictures of the bottom of the board?
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Need help with Cobra 2000 gtl
- Thread starter Newman86
- Start date
Looks like someone cut the trace on one of the leads of the 11.3258 tripler Crystal. They added a little tank circuit in series with this lead of the crystal for whatever reason. Looks like they were trying to put something on frequency. If I had to guess they might have modified the clarifier and we're having trouble getting all modes to Center up. This might have been done in an attempt to remedy that issue. To test this just remove them and jumper across that Trace to put the radio back to normal.
LC
LC
Hi Newman , # 1 welcome to the forum . Number #2 if you put your radio on Ch 38 , what frequency does the clarifier go to when you move it ( Low and High ) . Just curious , or have you disconnected it already ?
Any channel will work , I just used that for a reference , try channel 1 and see if it goes below . Like said " I was curious " if LC tells you something run with it he knows far more than myself . I joined a few years back and have learned a lot from him and the others . I was curious because I own a Cobra 2k and my clarifier goes to the next channel " and beyond ". ( Just the way I got it ).
the counter in the 2000GTL is made to compensate for the SSB offset and won't display the change. (if that is what you meant by your last post)
the C945 is a transistor and is probably just fine. i would leave the clarifier mod in if the radio is working. do all the steps i list here and then change the clarifier mod if desired.
If the radio was here in my shop, step one would be to clean the junk out of it with some chip brushes and then clean all the pots and switches with contact cleaner.
then i would remove all that brown glue that is all over the place, as it is corrosive and becomes conductive over time (guaranteed it is already starting in your radio).
you need to unsolder the parts from the board and clean them completely. there are videos on youtube on how to do this as well as what to use as a solvent for the glue.
DO NOT just scrape and pick at it!
after that, replace ALL the electrolytic capacitors with brand new ones. this includes the caps in the freq counter module. be careful here as this board is double sided and plated through, meaning that you have to get ALL the solder out before trying to remove the part. failure to do this right results in pulling the sleeve out of the board.
you can buy cap kits on ebay from klondike mike. (my opinion is to avoid the other cap kit sellers out there)
once all that is done, then do an alignment on the radio. you need to get all the basics done before you troubleshoot an old radio like that.
If all went well, i would then remove that cap and coil and see what change it made, and whether or not it needed to be in there. (my guess is that it doesn't)
there is no point in trying to fix a radio that has caps that old in it. you will only be chasing your tail.
LC
the C945 is a transistor and is probably just fine. i would leave the clarifier mod in if the radio is working. do all the steps i list here and then change the clarifier mod if desired.
If the radio was here in my shop, step one would be to clean the junk out of it with some chip brushes and then clean all the pots and switches with contact cleaner.
then i would remove all that brown glue that is all over the place, as it is corrosive and becomes conductive over time (guaranteed it is already starting in your radio).
you need to unsolder the parts from the board and clean them completely. there are videos on youtube on how to do this as well as what to use as a solvent for the glue.
DO NOT just scrape and pick at it!
after that, replace ALL the electrolytic capacitors with brand new ones. this includes the caps in the freq counter module. be careful here as this board is double sided and plated through, meaning that you have to get ALL the solder out before trying to remove the part. failure to do this right results in pulling the sleeve out of the board.
you can buy cap kits on ebay from klondike mike. (my opinion is to avoid the other cap kit sellers out there)
once all that is done, then do an alignment on the radio. you need to get all the basics done before you troubleshoot an old radio like that.
If all went well, i would then remove that cap and coil and see what change it made, and whether or not it needed to be in there. (my guess is that it doesn't)
there is no point in trying to fix a radio that has caps that old in it. you will only be chasing your tail.
LC
You've already seen my sales pitch on eBay and rejected it, going for the cheaper ones. You are not the first one to make a purchase based on the lowest price. I also would like to thank LC and many others from this site, who over the years have recommended and purchased my kits. Here's what you missed out on;
- Guaranteed quality, fresh parts. No hidden China gems.
- component values that meet or exceed stock. Over the years, technicians/hobbyists have discovered that some values if changed, improve the the operation of the radio. Many of those improvements are incorporated into my kit. No other kit has this. They just read from the service manual and provide whatever is listed. Under rated voltages, documentation errors and all. I eat my own dog food here and install my own kits when working on a radio.
- Additional documentation. Actual color photo's of the radio with component locations shown. Better than any SAM's manual.
- My kit is not the cheapest but I believe is the best bang for your buck. Buying a capacitor kit is similar as buying gas for your car. Not all are the same. Some are better than others if you do your research. BTW, I offer members of this site a $1 discount as well.
https://www.ebay.com/itm/142035580095
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cheap chinese no-name junk capacitors with dubious manufacturing techniques.
basically the quality of caps you would find inside a walmart wall-wart.
LC
Visit the link below and take stock of what you get;
https://www.badcaps.net/forum/showthread.php?t=388
https://www.badcaps.net/forum/showthread.php?t=388
Having made the mistake of buying a non-Mike kit I can tell you that you may receive lower quality caps, incorrect caps, not enough caps, and shorted caps.
Another tip of my hat to Klondike for the cap kit for this HR2600 just revamped a week ago. I will buy from him again and probably again... again...and... again!