View Full Version : cobra 25 nw wx st

01-24-2016, 11:15 PM
working on brother and laws cobra 25 nw wx st . It will only key 3 watts but swing to 25. sounds fair on the air has 1969 final looks to be original. took out c6 no change removed tr14 I think that was the # no change. played with coil would get worse but not better. Is this common for this radio. Any info on mods would be great. driver looks to be stock. Thanks.

01-25-2016, 04:55 AM
Check that there isn't a swing mod installed. It might be on the solder side of the board near the final. And it will or may consist of a cap and resistor. Have you checked that the AMC is still intact? If it's not, that would be the 1st thing I'd replace. Also check out Angelfire.com for all the things that can be done to those radios. Just use google. This may help you find the cause of the problem as well. Just make sure that the AMC circuit is still working, if it makes no change to power when turned, then it's most likely been clipped or is bad. Good luck and hope you get it resolved.

01-25-2016, 05:13 AM
And also check tuning of L10, L9, & L8 as I believe they are part of the power tuning procedure. Also check D19, TR14, and VR5. And like I said look at the mod limiter (D9, I think), and see if it's been cut. Might not be noticeable as all it takes is a small snip of wire to disable it.

01-25-2016, 05:14 AM
Replace TR14 is you removed it. JMO.

01-26-2016, 01:05 AM
Hey, Thanks HT d9,d19,t14 and mod limiter all put back in. no swing mod. I tried that myself when I keyed the mic dk 3w then when you talked needle on meter would go backwards to zero. I took it out. Now dk 2w swing to 10w. Thanks again for the help.

01-26-2016, 05:22 AM
No worries. Hopefully I lead you in the right direction. Tuning is not truly easy to do without the proper test equipment, but you can get it pretty close if you don't crank all VR's wide open. Leaving some headroom is always better than being distorted. Again, JMO. Have fun messing about. Saw where you posted on the other forum. I am 222DBFL on that forum, and used to be the same here. Had an email change so had to register again. But at any rate, have a good one and keep at it. Look into getting some test gear if you really plan on messing with radios the right way. A good O-scope, freq counter, volt meter, VSWR/power meter, a good dummy load, And all the necessary probes and such. I am not a tech myself and damn sure don't claim to be one. All I know if from my own experiences with messing with the same or close to the same radios. At any rate, keep it clean and mean!!! Good day.

01-27-2016, 01:56 AM
The dosey power meter w/ frequency counter does radio have to have plug for freq counter to plug into from meter. I thought i saw 222bfl on other forum. Thanks for the help. Are dosey's very accurate. I have a radio shack meter.

01-27-2016, 01:55 PM
Dosy meter, radio
Shack meter, all about the same. Like others have said, save your coin and get an oscilloscope.

01-27-2016, 02:41 PM
Thanks, ht i will check in to that.

01-28-2016, 05:18 AM
Here are a couple, one much more expensive than the other. Both will basically do the same thing for what you need them for. http://uploads.tapatalk-cdn.com/20160128/c0212de4ea8fa17f9c14e3bd60608771.jpghttp://uploads.tapatalk-cdn.com/20160128/bc7bc6b253e101fbb7e1478288e9d50a.jpghttp://uploads.tapatalk-cdn.com/20160128/8476fa60879d2914081d46d65748c0d0.jpghttp://uploads.tapatalk-cdn.com/20160128/26fa9fcddc35685f909a818dc23fcec6.jpg
Good luck and keep at it man! It's fun to learn, but even better to learn the correct way. JMHO. Have a great day.

02-01-2016, 01:39 AM
Thanks a lot heavy hitter, I will check those out for sure. I appreciate you taking the time to post hat for me.

02-01-2016, 05:50 AM
No worries. And I am no Heavy Hitter that is for sure LOL!! Just a duck stuck in the Mud! Don't run much power here anymore. 100w is about max for me. Have a couple amps in the closet that could get me to about 1kw, but that is just tickling feathers!! I am just a run of the mill cb'er that has seen the light and boy it gets blinding some times!! Keep it clean and mean!!
73 and God Bless.