The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

I am having problems with my SWR or maybe it's normal.
I recently had a final upgrade done on my Cobra 29 WX NW ST .
I had a ERF2030 final installed and a EN1230 at a shop in London, Oh - right behind the TA .
Before I had this "hot final" job done I had my Radio Peeked & Tuned and all was well , I just wanted to try to squeeze a little bit more out of my radio by changing the final.
Well as soon as I re-installed my radio I noticed that when I tried to calibrate and set my SWR I now have to turn the SWR knob just about all the way to the right and before I had the final replaced I only had to set the knob a little past half way. ( Before any one asks- yes I set my SWR on ch 20, 40 & 1 in cal mode and while still keying the mic I switch from cal to swr ) Also I have noticed it seems like my receive is less.
I did take it back right away and the claims that every thing is okay and I am putting out about 45-50 watts. I am fixing to take my radio to a shop here in San Antonio, TX before I go back on the road and I just wanted to see if anybody had an input as to what my problem might be.
Sorry for being so long winded I am a detail-oriented person and I just wanted to be clear about my problem. Thanks

Well they may claim everything is alright but I can tell allot of these guys have no idea what they adjusted inside your radio and almost every time one of these radios comes across our bench it 's a sure bet they have been turning everything they can in an effort to try an get more power and that usually means you most likely need to have it aligned properly. As far as the not being able to calibrate the swr meter inside the radio they have probably set the dead key to low to allow it to calibrate as a rule the radio has to produce over 2 watts of dead key before full scale calibration can happen more than likely the dead key is below that.

Dennis
Platteview CB Shop Nebraska

It does indeed sound like the dead key is causing the problem, the fix is simple, get the dead key up another watt or so and you will be able to calibrate the meter. Sometimes after installing the ERF2030 the deadkey does not always go as high as it did. A lot of people prefer the lower dead key, but if you need it higher to fix your swr calibrate issue, most any competent CB shop will be able to help.

If they have installed the swing kit mod.
All you will need to do is change the value of the resistor,
to about 51-68 ohms,this should give you about 2 or 2 1/2
watt dead key.The swing kit mod is installed in the left
rear corner of the radio pcb,with the knobs facing you.
It will be a 220-470 mfd elect. cap installed in the holes
previously occupied by jp-36 jumper.The resistor that will need
to be changed,will be on the foil side of the pcb,across this same
cap. connections.

Like ramblingman said, if there is a swing kit, a resistor change is all you need. I have found on the Cobra 29's wth the ERF2030 and the EN1230 Bias chip, the value of the swing resistor is a very low value, usually in the range of 3-10 Ohms, instead of 33-86 Ohms used with other finals.

Try a 3 Ohm for starters, if there is a swing kit.

i am very interested in how an erf 2030 mosfet can generate 45-50 watts in a cobra 29. maybe someone at that cb shop has a "majic meter", now u see it, in the truck you don't. i went to that shop a while back, and was not impressed.i was an otr trucker with 30 plus yrs experience untill i lost my lt. leg. i have been in a lot of "shops" and seen some real "majic". i,on the other hand, have been in some really excellent shops and have seen some astounding tech's. a while back i was able to b taught by several hi quality tech's and they allowed me to work the bench. i am NOT a great benchman by any means,just fortunate to have some good teachers. mosfets were just coming into existance when i had to quit,so i am interested in the power capabilities of them. let me know,please! maybe that shop has changed hands,hopefully 4 the better. thanks. oh,yeah, usually when the power goes up,so does the s.w.r.