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Message |
    
Possumz
New member
Username: Possumz
Post Number: 9
Registered: 9-2004
| | Posted on Friday, November 05, 2004 - 11:03 pm: | 
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How do you volt the final on a Cobra 29 ltd. I have a few spare 29s i like to play with. Anyhow i would like to increase the volts.
Possumz |
Therealporkchop
Member
Username: Therealporkchop
Post Number: 73
Registered: 11-2002
| | Posted on Saturday, November 06, 2004 - 10:08 pm: |
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Me too, this will be a good one. |
Possumz
Junior Member
Username: Possumz
Post Number: 10
Registered: 9-2004
| | Posted on Sunday, November 07, 2004 - 4:47 pm: |
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I know someone here knows how to do this. I seen it done some years ago on a Cobra 25 and 29 LTD at a Keydown competition. I know its possible just dont remember how it was done as i have been out of the cb scene for 5 years.
Possumz |
Therealporkchop
Member
Username: Therealporkchop
Post Number: 75
Registered: 11-2002
| | Posted on Sunday, November 07, 2004 - 9:47 pm: |
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Seems lately nobody answers these post. What is going on here guys? Seems these are the secrets nobody wants you to know. Nobody tells the really good stuff. |
Tech808
Moderator
Username: Tech808
Post Number: 4050
Registered: 8-2002
| | Posted on Monday, November 08, 2004 - 12:25 am: |
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Therealporkchop,
If a Question gets no replies then probably no one has the information for you.
The Only radio I have ever volted finals on in the past is the GrantXL the mod is below,
#1 ~ Perform the "NPC-RC" mod first.
#2 ~ Turn AM power (VR10) ALL the way down (use watt meter and dummy load to verify)
#3 ~ Unplug power from radio and find "TP8" wire (purple- green on old boards) near VR7.
#4 ~ Clip TP8 wire, separate and tape or use heat shrink tubing to keep open ends of wire from shorting on anything.
#5 ~ Access pc trace side of board and solder a heavy gauge wire from
the C148/L39 (C146/L39 for old board)trace junction to the 13.8+ pos. input coil/red wire/C188/D55 trace junction
#6 ~ Add a jumper across R196
#7 ~ Apply power to the radio and re-adjust VR10 for a dead key of 2 to 2.5 watts-
verified on watt meter and dummy load.
The XL will now dead key 2-2.5 watts and will be dependent on AM modulation input
for an increased RF output upwards of 20 watts peak.
*************************************
The person who paid for the NPC Mod and Volting was NOT HAPPY as he had heard of GIANT GAINS that just were not there and considered it a complete waste of time and money.
Lon
Tech808
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Therealporkchop
Member
Username: Therealporkchop
Post Number: 76
Registered: 11-2002
| | Posted on Monday, November 08, 2004 - 12:56 pm: |
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I understand what you are saying. But as a person trying to learn new stuff, I've found it hard to get anyone to tell you the "secrets" if you want to call them that. Granted alot of guys here, including you Tech808, have supplied plenty of tips and tricks. But when it comes to asking for tricks of this nature, or asking someone for repair info, (i.e. - my radio keys, but no audio) nobody seems to want to help out. It's like true techs are scared to just tell someone what to look for or what to replace because they are scared that they won't get the repair and make the bucks.
I know that that is what techs are in this business for, but nobody seems to want to share their knowledge with newbies, and they don't seem to want to share info on how to get into the repair field. I'm not hacking on anyone here, I'm not harping or complaining. I'm just stating how I feel about it. Seems there is the same problem between Techs & Newbies as there are between HAM operators and CB jockeys. And if I've failed to thank anyone here for anything, help or advise, then I take this time to say "Thank You". I hope I haven't stepped on any toes here or offended anyone.
Now, does anyone happen to know how to volt the final on a Cobra 29LTD Classic? |
Johnhenre
Junior Member
Username: Johnhenre
Post Number: 49
Registered: 1-2004
| | Posted on Monday, November 15, 2004 - 9:09 am: |
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IT SEEM AS SO TO THEREALPORKCHOP AS THE SAME AS HIS OUESTION THAT I'M GOING TO ASK ALSO? ABOUT A GALAXY DX 959; HOW DO YOU GET AN ADVERAGE 20 WATTS PLUS OUT OF THIS RADIO AT ALOW 1 WATT OR LESS(THE SWING)? I'VE ASKED,ALSO LOOKED IN ALL OF COPPER'S FORUM AND CAME UP WITH (ZERO)ABOUT THE COBRA 29 INCREASE VOLTAGE,AND HOW TO GET WATTAGE OUT OF MY (PLAIN JANE)DX 959 RADIO SO IF THERE IS'NT ANY WAY THAT THIS MIDDLE PRICE RADIO CAN BE IMPROVED BUYERS SHOULD BE AWARE OF IT'S OUTPUT AT LOW DEAD KEY. BOB (PS) THERE IS A TECH THAT IS SELLING KIT'S IN KY. FOR DX 959'S WITH A GUARANTTE OF 20WATTS+ AND HAS A FEEDBACK OF 100% FOR A COUPLE OF YEARS. JUST ASKING IS THIS SOME KIND OF SECRET???????? |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 208
Registered: 7-2004
| | Posted on Monday, November 15, 2004 - 1:03 pm: |
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i have probably messed with every single modification i have ever seen, even purchased radios to specifically try a mod. i just wanted to be able to say i did it and it did/didn't work. MOST weren't worth the time and effort for what my ultimate goal was. dead keying a 29 or grant xl or 959 at 1-2 watts, and swinging 10-12, which is EASILY obtainable, probably will show NO NOTICEABLE difference over the same radio swinging 20 or so watts. for more than that you need to swap transistors, again hardly worth the effort. use that 2 watt dead key/12 watt swing to drive a 1-2290 amp, like a texas star modulator, or xforce or magna force. my grant xl has a variable output, less than 1 watt to 4 watts, and will swing at least 12 watts, all of my 2-2290 boxes on 13.8volts swing at least 120 watts, up to 165, and can dead key less than 40 up to almost 100 watts. except for audio tone differences, there's no noticeable difference in signal, even when driving my dx 1600, 100-200 watt swing doesn't show much signal difference.
i've seen every type of question possible attempt to be answered on this forum. if nobody responded, it's not because they're hiding info, the right person just may not have seen your question. and, if someones response is way off, someone always jumps in to correct him. and, lastly, try searching different variations of wording , cobra 25 modifications; cobra 25 variable wattage mods; cobra 25 swing kits; etc on your internet search engine. you'd be surprised at what pops up sometimes, then if you have a question on what you found, try posting it here and see what kind of response you get...
jus' tryin' to help, chop & john! |
Allagator
Advanced Member
Username: Allagator
Post Number: 511
Registered: 9-2002
| | Posted on Sunday, November 21, 2004 - 3:59 am: |
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All i have to say is VOLTING the 29 will not do you any good !!!
i have seen a few modded that was volted but that is a diff subject !!
a stock 29 volted make's it get HOT and REAL HOT
but with a few mods and a few bucks it can be done !!!
but most people are into the export radios anymore so i have kinda lost touch on the tricks but i wil look up the mods for ya if you realy want to try it !!!!
Allagator
P.S Volted 29 does not do no more than 25 watts !
a volted 29 makes it stay at 0 to max power ! yes it will have great audio ! but for how long ???
but its just my 1\2 cent !!!
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Monk
Junior Member
Username: Monk
Post Number: 20
Registered: 2-2002
| | Posted on Thursday, November 25, 2004 - 3:01 am: |
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You don't volt the final in AM only raidos. The final is already at close to the supply voltage~~13.8 volts.
When you hear of volting the final it refers to the SSB type of radios which have a regulator circuit that supplies around 6 volts to the finals in the AM mode. To volt the final the regulator circuit is bypassed and the final supplied with the input voltage ~~13.8 volts.
I have heard of people cranking up their power supplies to 15 or 16 volts to get more power out of their radios. IMHO they are wasting their time and unduly stressing their raidos. If you want more power get a bigger kicker.
Monkradio |
Therealporkchop
Intermediate Member
Username: Therealporkchop
Post Number: 103
Registered: 11-2002
| | Posted on Friday, November 26, 2004 - 1:34 am: |
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I have to disagree...
I read somewhere, but I can't recall it right now, and I am not going to mis-quote somebody either. I saw where you could increase the power output by doing this. The guy that wrote it has many years of experience and I think he knew what he was talking about.
Anyway, this isn't a quest for power, it's a quest for knowledge...Also just something to do while sittin' around in the shack killin' time. This is a hobby fella's, and this is the kind of stuff you do in a hobby. Experiment and have fun. CB is a hobby, just as Ham is a hobby. Which ever you are into, you are into it to have fun...and that is all I am after in wanting to know how to do this and I am sure Possumz feels the same way... |
Inspector
Intermediate Member
Username: Inspector
Post Number: 109
Registered: 12-2001
| | Posted on Wednesday, December 01, 2004 - 12:17 am: |
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You can gain full voltage to the final stage by shorting out the anti-spike diode BUT you only add about 0.7V and you need the diode to protect the audio transformer from failure! |
Therealporkchop
Intermediate Member
Username: Therealporkchop
Post Number: 123
Registered: 11-2002
| | Posted on Friday, January 28, 2005 - 10:57 pm: |
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I believe I found some info about this on a web page. Basically you change the 1 ohm resistor that is directly in front of the final to a .47 ohm resistor. Or you could just jump that. It also talks of changing to the 1969 final, which I've done before as well. I jumped the resistor and I only saw like a watt or two increase, hardly worth doing it.
I've always read here about how it is so impossible to get a radio to swing past 25 watts or so. You guys need to come to North Carolina, must be something in the air here. I have that same 29 swinging 30 watts PEP without the 1969 final. I've got two more that have the final, and they both swing 40 watts PEP. I guess this will always be a debate though...in the words of Eric Cartman..."I love you guys" |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 371
Registered: 7-2004
| | Posted on Saturday, January 29, 2005 - 10:16 am: |
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a single 2sc1969 is only rated at about 21 or 22 watts pep output with 1 watt input. for keydowns, i've seen 29's NARROWBANDED, to where everything is forcibly aligned to somewhere from ch 1 thru 10 or so, and not just 'volted', but volted to the edge of it's life, along with being force fed as much drive as possible. not the least bit efficient for use as a means of communication, nor very long for this world, repairs are done frequently. better chance of seeing 40 watts using 2sc2132's, then again i've seen a few dosy's (maybe it's supposed to be doozy) that will really open up your eyes in disbelief.
but, hey, my 100 bird watt mobile has taken out more then it's share 750 watt dosy readings...and though interesting to watch, a keydown has no effect on my ability to get out with 3.5 watts dead key and 12 watts swing input... |
Therealporkchop
Intermediate Member
Username: Therealporkchop
Post Number: 125
Registered: 11-2002
| | Posted on Thursday, February 03, 2005 - 3:09 pm: |
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Like I said, The Great Debate!! I am not saying my radio IS swinging this amount, nor that my meter is 100% correct. I do know that I adjusted my meter to a Diamond that had been set up from a Bird 43 Thruline. I take my readings off a dummy load connect via a piece of RG213 about 1 foot long. I've read all the literature about the 2SC1969 and that's 22 watts PEP output from 1 watt CW, not PEP. Either way, this makes for a fun topic and discussion. It could be the difference between meters, who knows? For the true hobbist, it makes for fun time in the shack and talking to cb friends!! If a guys gives you a good signal report and says it sounds good, then just enjoy the radio regardless of what it swings.
I just thought I'd mention what I had read about the final voltage mod though.
Later |
Fusebreaker
Junior Member
Username: Fusebreaker
Post Number: 24
Registered: 3-2004
| | Posted on Thursday, May 12, 2005 - 2:47 pm: |
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remove diode D-8 it will give an extra 0.8 volt to the final |
Fusebreaker
Junior Member
Username: Fusebreaker
Post Number: 25
Registered: 3-2004
| | Posted on Thursday, May 12, 2005 - 7:19 pm: |
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o ya install a jumper too |
Sparkomatic
Intermediate Member
Username: Sparkomatic
Post Number: 387
Registered: 10-2002
| | Posted on Friday, January 27, 2006 - 6:50 pm: |
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The mods that were done on my Malaysia Cobra 148 allow my dead key to be turned down to 0 and up to 15 watts. The peak swing is about 20+ and the way I run mine is with a dead key of 1/2 watt swinging to 10 watts on Bird 43 with a 50 watt element. May not be a huge gain over the stock peak and tune but the swing gain will be big with an amp. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2315
Registered: 7-2004
| | Posted on Friday, January 27, 2006 - 7:19 pm: |
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10 watts RMS swing on a bird is GOOD. the keydown guys look to get 'em around 12 RMS swing, so you are real close. once PEP swing gets much past 20-22, start looking for all that extra swing on about 10 or 20 channels, the neighbors TV, etc  |
Weatherman49
Junior Member
Username: Weatherman49
Post Number: 44
Registered: 2-2005
| | Posted on Saturday, January 28, 2006 - 1:35 pm: |
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ok guys has any one thought of mentioning the ekl finals to porkchop and possumz apparently they have the capability to produce 40w pep out of a cobra 29 or its uniden twin the instructions are listed on this forum as well as many other places as far as I know Copper dose not carry them yet but will I am waiting for Copper to stock them so I can order a new radio and the finals at the same time. so I say the heck with volting and burning up a radio! I have done the 1969 swap and all the other good jazz to the 25 29 pc66 pc68 and got a max 25w so yall tell me witch would ya rather have 25 or 40? by the way possumz I asked the same Q about a year ago apparently its an absolute mystery!! LOL good luck on your mods |
Weatherman49
Junior Member
Username: Weatherman49
Post Number: 45
Registered: 2-2005
| | Posted on Saturday, January 28, 2006 - 1:39 pm: |
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possumz go look in the topics under subsriber preview and it will give you the info for the ekl swap the parts are en-1230 and erf-2030 |
