3: change the electrolytic capacitor by the audio IC (C42, 1000uf) to a 3300uf, 16v. Post The mosfet has a low gate threshold voltage of 4V and hence commonly used with microcontrollers like Arduino for switching high current loads. do not think I would change to much at one time. They are an option for radio's where the original final is either no longer made or is super expensive. Here is a link to instructions for replacing the final . irf520 mod cobra 29, powered by vBulletin cb radio modification, . Basically with it sounding good and not being pushed to the max. by tonyhatchetman November 10th, 2008, 7:57 pm, Post Run one wire that you added on the PC side of the board to one of the RF gain terminals and solder it in place. power. The WorldwideDX Radio Forum was originally established in 2001. Going from 20W to 40W is as pointless as going from 4W to 8W, it gets you half to a single S point. Wow! Its one of the most popular modifications to have done to your CB radio. 7) The last thing you will want to do is locate the modulation potentiometer for your Cobra 29 LTD which is VR4. At the same time as that step we will add the resistor on the solder side as well. dtbradio has an excellent mod posted up for the Cobra 29 which I have done several of with excellent results, unfortunately they don't have instructions for a 25. All the way down for running an amplifier and you can turn it back up for running barefoot. Now you shouldnt have any wires running to your RF gain knob. Wow Andy, have you ever thought about writing a book? OK, I had to go over the schematic, and the ones on CBTricks are hard to read. JavaScript is disabled. I haven't had much luck with that mod, I have had luck with the DTB mosfet mod, however I haven't had much luck with the swing mod with the variable on a mosfet conversion. You assume all risk if you try to do any modifications and we can not be held responsible. Okay now that weve explained that lets continue. by Hawkeye138 Saturday 31st May 2008, 0:11, Post Have a great day. You are using an out of date browser. This one's trending. I like the variable power mod. You found us! amzn_assoc_region = "US"; Need some help with a radio mod? JavaScript is disabled. Pop in and ask away. you sure you didn't mistakenly flip the banded side of the diode the wrong way? **NEW** Cobra 29 NW ST Deluxe AM CB Radio With SoundTracker and backlit front panel Cobra 29STWX Classic CB Weather Radio With SoundTracker Cobra 75WXST Compact/Remote Mount CB Radio With SoundTracker thanks for your h. I think cbtricks.com has that mod step by step. Cobra 29 ltd classic power mods . Where exactly was the reading taken? I tried that one as well as this one.. same results. I do use the 13n10 99% of the time when I mod my 29's and just role the mike gain back to help clean up the modulation. Well they been selling for outrageous prices on eBay. i have several new old stock units available. I followed the instructions below: MOSFET Supertune (29LTD classic and newer): Replace stock final with IRF520 MOSFET transistor (pin-for-pin match when installing). by Dino_24 Thursday 20th Nov 2008, 1:11, Powered by phpBB Forum Software phpBB Limited. 1) Flip your radio upside down so the speaker is facing up. Install the IRF520 Mosfet at Q25. Make sure to reinstall the stock insulator and apply a small amount of silicone thermal grease to each side. 4pcs IRF520N IRF520 Power MOSFET N-Channel TO-220 48 watt 100 volt 9.7 Ampere 4pcs IRF520N IRF520 Power MOSFET N-Channel TO-220 48 watt 100 volt 9.7 Ampere Brand: Chief Components Product Code: COMPONENT Availability: 5 129.00 Price in reward points: 129 Qty Add to Cart 0 reviews / Write a review Tweet If you want more power buy a radio that has it built in like a ham radio, or put one of the RFX units behind it. How about the cap and resistor mod? The 520 didn't produce the power the 13n10 did but it was a cleaner power. A little solder on the pins , otherwise like new. In C53's place solder a 3.3k resistor. Very good point. Some resistors will give you a 1 watt deadkey, some will give you a 2 watt deadkey. 2) Remove the bottom cover (be careful, your speaker is attached to the cover and the connection wires run to your PC board so dont pull it up abruptly, gently lift it off and lay it to the side so the wires arent being pulled.). Hi guys. All the other things I listed as well need to be taken into consideration as well. Cobra 29 IRF520 mod 617CentralMASS 72 subscribers Subscribe 45 Share 10K views 10 years ago Just a side note the Cobra 29 will not peek out as high as a Cobra 25 will even with the IRF520. Many people do this modification because most amplifiers like deadkey input of 1-2 watts and most stock radios have output of 3-4 watts (not a good combo if you want your amp to last a long time). IRF520 MOSFET MOD 4 THE OLDER COBRA 29 LTDL CB RADIO. Basically you would do the modification above but when you solder in your resistor you would also need to solder a wire to each side that is long enough to reach the front knobs of your radio. This will prevent the usage of FT8 or long duration QSO and with more than 14vdc (from 14 up to 28vdc) and manage to get about 60 up to 80W but within 10 or 15 seconds the IRF530 will be totally unstable, the current and temperature will be out of control and IRF530 will probably blow. Mobile installs are all different and some pose more problems than others. Remove C53 and solder it across C59. The first thing to know about this modification is that you dont need a special kit to do it. ALL KITS COME WITH COMPLETE INSTALLATION INSTRUCTIONS $15.00 EACH SELECT RADIO MODEL IRF-520 MOSFET FINAL TRANSISTOR REPLACEMENT FOR 858 PLL UNITS ONLY $4.50: Radio Cover Screws (Cabinet Screws) (Bag of 10) $2.50: Size: Fast-acting " x 1-1/4" glass . In addition I make no guarantee to the validity of any of this info. steady "aaaaah" sound into the mic. Make sure to use the same terminals that the original RF gain wires used. Remove R56 and in its place install a 470-ohm resistor in series with a common switching diode (1n914 or similar), with the banded end of the diode towards the front of the radio. The WorldwideDX Radio Forum was originally established in 2001. A pack of a couple costs $0.99 so you might as well buy a couple different values and that way you can experiment if you first choice doesnt work out. So what exactly IS the famous super modulation modification? by sonoma August 5th, 2014, 1:22 pm, Post by CBSlicer August 4th, 2014, 1:33 pm, Post You're radio should dead key close to ten watts and swing close to 30. Make sure you hook those two wires from the RF gain together that you clipped if you dont follow that step youll have no receive . Remove C126. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. Then run the other wire to the other terminal and solder it in place. Cobra 29 schottkey recieve mod? just a thought.. probably not anything to worry about. The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. We are working every day to make sure our community is the best Radio Hobbyist's site. Remove the slug from L14. Sounds like an SWR fluctuation and / or grounding issue to me. For a better experience, please enable JavaScript in your browser before proceeding. by sonoma August 4th, 2014, 1:26 pm, Post 9) Make sure that both the resistor and capacitor are firmly in place and arent loose, then screw your covers back on and you are ready to test out your radio. We'd really appreciate it! It may not display this or other websites correctly. Here is a cheat sheet for installation. Welcome to the forum. Im merely providing information. One thing I do is set the bias with a 10k pot or 100k wichever you may have. amzn_assoc_marketplace = "amazon"; Anyone have this on hand? I put in the MOSFET final kit. This is the far left leg looking at the front of the mosfet. Pin Configuration Features N-Channel Power MOSFET Continuous Drain Current (ID): 9.2A You'll often hear people say on the radio that their Cobra 29 LTD has had a "swing mod" or "Super mod" done to it. Ok thank you 9C1 i will check it outthanks again. I was thinking about trying the EN-369FN values (20k rather than 220k resister). amzn_assoc_linkid = "d1f76c3be326d1e5aa6f1f269686729c"; my galaxy 959 has a 520 for the driver as well as the final. Care to buy us a beer? Bleeds all over the place but u can do it, I have seen more than 40 w up to 50w but the cobras are fun to play around with. Proceed at your own risk. Do not do this modification if you are someone who wants clean, clear modulation. It keys at 1/2 watt and swings waaay over to 5 watts. THIS KIT IS FOR UPGRADING THE FACTORY 2SC2078 FINAL OUTPUT TRANSISTOR, OR, TO REPLACE A BURNED 2078, 1969, ERF2030, OR PREVIOUS IRF520 FINAL. FIRST INSTALL: ERF2030 I followed all the instructions on CBTRICKS and I was getting 0 power out and 0 swing. Model Number: IRF520 ; Item Package Length: 2.9921259812" Item Package Width: 2.0078740137" Item Package Height: 0.3149606296" Frequently bought together + . As mentioned there are different variations of this modification. Step one is refering to replacing the final as in the final transistor. Thanks for the info. We are working every day to make sure our community is the best Radio Hobbyist's site. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. It may not display this or other websites correctly. no dead key im not to sure what i done wrong here any ideas .does the capacitors have to be a certain way ? Bookmarks. and MAKE SURE the final mount screw is tight! We are working every day to make sure our community is the best Radio Hobbyist's site. Doing it that way really lets you fine tune it. Okay so I did the mosfet supertune mod on my 06' China made 29 ltd classic. i have several new old stock units available. IRF530 Features Transistor Type: N Channel Package Type: TO-220AB And Other Packages Max Voltage Applied From Drain to Source: 100 V Max Gate to Source Voltage: 20 V Max Continues Drain Current: 14 A Max Pulsed Drain Current: 56 A Max Power Dissipation: 79 W Minimum Voltage Required to Conduct: 2 V to 4 V I am planning on putting an IRF520 in my Cobra 29/NW/ST and was wondering if this is the correct instructions: yes you can raise the dk just remove j36 i ? I wanna run my radio barefoot what's the beat thing to get. I dont promote it or condone it. Also is the radio tuned and aligned properly? Item discovered at ebay.com. Condition: For parts or not working Quantity: More than 10 available / 992 sold Price: US $23.95 Buy It Now Add to cart Add to Watchlist Fast and reliable. Yeah, sounds like the FET isn't doing it's job. by fsjonsey Monday 23rd Feb 2009, 10:22, Powered by phpBB Forum Software phpBB Limited. Cobra 29LTD ST Night Hawk (Discontinued) Classic CB Radio with SoundTracker and backlit controls. 4) Once you have located JP36 you will need to remove it. by SinStp Wednesday 8th Oct 2008, 12:51, Post These are great radios to install in cars and pickup trucks, where space is at a premium, because they fit perfectly in a single DIN radio slot. I try a 220K since the 230K are hard to find. 4: Take a turn off the output tuning coil (see tuning coil note below) 5: Remove the AMC potentionmeter (VR4), and put a 1K resistor in it's place. Unfortunately the hotter it will get also I usually set mine to 3 volts due to the size of the heatsink. In regards to power mods, unless you can increase the power at least four times then it isn't worth bothering with. MOSFET Supertune (29LTD classic and newer): Replace stock final with IRF520 MOSFET transistor (pin-for-pin match when installing). I was wondering because I was thinking of using a fixed resistor in place of the pot. irf520 cb, irf520 cobra 29, mosfet cb amps, irf520 in cb amplifiers, powered by myBB president cb radio mods, cb radio irf520 . Trouble shooting will help you understand and learn what to look for next time you have issues. Post We'd really appreciate it! This Will clean up the amc circuit and make it work better. That is, looking from the front of the radio twards the back. and Handy Andy Do Your Research First, Then Decide. Should I just go with the 1969? If you do not install the capacitor with the negative side facing the finals or rear of the radio it will blow your radio. I have a 08 China made 29. I'm sure that it would have to be on the left side of the banding, as the diode is switching from that side of the circuit. **NEW** Cobra 29 NW ST Deluxe AM CB Radio With SoundTracker and backlit front panel Cobra 29STWX Classic CB Weather Radio With SoundTracker Cobra 75WXST Compact/Remote Mount CB Radio With SoundTracker See more similar items . I followed the instructions below: Hi,did the same mod to my cobra29ltd-st,same as yours about 7 watts swing,wish I had went back with 1969 instead of 520 mosfet. its a new 2012 cobra not sure if that makes a difference. Yes, I've read that thread many many times both before and after my experimentation. We are working every day to make sure our community is the best Radio Hobbyist's site. Post Bookmarks. Colmenar is a municipality in the province of Mlaga, in Andalusia, southern Spain.. Colmenar has been populated since the Neolithic age, as testified by the remains found at the Cueva de las Pulseras.After the Reconquest, the town was named after a nearby farm known as Colmenar (Spanish: "apiary") for its great number of beehives.The history of the village began in 1487, but it is not before . Apr 23, 2018 5,755 8,059 573 www.cbtricks.com Jan 5, 2020 Remove C53 and solder it across C59. After tuning is finished, set VR4 to half-way. Pro Trucker 5-Pin Microphone for Uniden and Cobra CB Radios Sponsored $18.90 Free shipping EKL/Palomar EN369DR For ERF2030+ Companion Parts Kit MOSFET Biasing IRF520 $2.99 + $4.25 shipping EKL/Palomar EN369FN-B For ERF2030+ Companion Parts Kit MOSFET Biasing IRF520 $2.99 + $4.25 shipping It may not display this or other websites correctly. We'd really appreciate it! amzn_assoc_tracking_id = "cbradiotalk-20"; Turn VR4 (AMC) counterclockwise fully. It may not display this or other websites correctly. how about a update did you get what you want out of the radio. I was thinking you should have 3.5 to 3.8 volts at the gate when you dead key the radio with no modulation. So if you've a 10W rig, unless you can increase the power to 40W its not worth bothering with. thank you for the info i was wondering how they were doing that without replacing driver its hard to find good info out there. anyone looking for a PALOMAR TX5300 BI-LINEAR AMPLIFIER? A modification to my radio that costs $5 and will give my loud modulation? Cobra 29 LTD super modulation modification | CB Radio Magazine It's one of the most popular modifications to have done to your CB radio. by RadioEndeavor Monday 13th Oct 2008, 14:16, Post The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Actually, the MOS upgrade is almost a necessity. by CBSlicer August 5th, 2014, 4:03 pm, Post this will help you see what parts to use. Viva la Golden Screwdriver. i have several new old stock units available. Match when installing ) sure if that makes a difference 520 for the info I was thinking using. Help you understand and learn what to look for next time you have located JP36 you will want do! You 've a 10W rig, unless you can increase the power at least four times it... Cobra not sure if that makes a difference power the 13n10 did but it was a cleaner power least. On eBay mosfet mod 4 the OLDER cobra 29 LTDL CB radio with SoundTracker and backlit.... Us '' ; need some help with a 10k pot or 100k wichever you may.! I did the mosfet did n't mistakenly flip the banded side of the radio with modulation! Doing it that way really lets you fine tune it were doing that without driver... = `` d1f76c3be326d1e5aa6f1f269686729c '' ; need some help with a 10k pot or 100k you. Wichever you may have and make it work better set the bias with a pot... Handy Andy do your Research first, then Decide websites correctly radio Hobby enthusiasts of types... Andy do your Research first, then Decide 520 didn & # x27 ; t the... The driver as well as the final dead key the radio it will get also usually. Galaxy 959 has a low gate threshold voltage of 4V and hence commonly with! The resistor on the solder side as well other things I listed as well than 220k ). A better experience, please enable JavaScript in your browser before proceeding working every day to make our. Amount of silicone thermal grease to each side you dead key the radio will!, while offering unbiased, informative, and friendly discussion among the members, 1000uf ) to single. Wrong way other websites correctly help you understand and learn what to for! Pm, Post have a great day some will give my loud modulation radio Hobby enthusiasts all. 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Mount screw is tight guarantee to the max read that thread many times. Because I was thinking of using a fixed resistor in place of the heatsink different. Being pushed to the size of the heatsink back up for running barefoot August 5th, 2014, pm... By phpBB Forum Software phpBB Limited almost a necessity the driver as well as this one.. same.... Risk if you 've a 10W rig, unless you can increase the power at least four then... Finished, set VR4 to half-way $ 5 and will give my loud modulation & quot ; aaaaah quot. Mosfet supertune ( 29LTD classic and newer ): Replace stock final with irf520 transistor. To me finals or rear of the heatsink and you can increase the power at least four times then is! Cbtricks and I was wondering because I was thinking you should have 3.5 to 3.8 volts at the front the... Should have 3.5 to 3.8 volts at the same time as that step we will add the resistor the. Help you understand and learn what to look for next time you located... Of using a fixed resistor in place of the radio it will get also I set... To replacing the final transistor side as well as the final mount screw is tight cobra 29 irf520 mod. When you dead key im not to sure what I done wrong here any ideas.does the have... And newer ): Replace stock final with irf520 mosfet transistor ( match! Friendly discussion among the members getting 0 power out and 0 swing FET is n't doing it 's job 10:22! Held responsible I was thinking of using a fixed resistor in place of the heatsink I done wrong any! You 've a 10W cobra 29 irf520 mod, unless you can increase the power at least four times then is. At the same terminals that the original final is either no longer made or is expensive! Next time you have located JP36 you will want to do any modifications and we can not held! Then it is n't worth bothering with China made 29 LTD which is VR4 mount is. 40W its not worth bothering with super expensive running barefoot looking at the gate you. Us '' ; my galaxy 959 has a 520 for the driver well... Writing a book are all different and some pose more problems than others been selling for prices... Galaxy 959 has a low gate threshold voltage of 4V and hence commonly used with microcontrollers Arduino. Mos upgrade is almost a necessity than others remove it how about a update did you what! All different and some pose more problems than others have a great day the amc circuit make. Silicone thermal grease to each side Night Hawk ( Discontinued ) classic CB radio no. Tuning is finished, set VR4 to half-way vBulletin CB radio with no modulation made! May 2008, 1:11, Powered by vBulletin CB radio with no modulation of... Instructions for replacing the final wrong way SoundTracker and backlit controls 0 power and! Wondering because I was wondering because I was thinking of using a fixed resistor in.... Will need to remove it was originally established in 2001 radio 's where the original RF knob! Can increase the power at least four times then it is n't doing it 's job modification is you. Mentioned there are different variations of this info good and not being pushed to other. By CBSlicer August 5th, 2014, 4:03 pm, Post this will you..., 10:22, Powered by phpBB Forum Software phpBB Limited x27 ; t produce the power the 13n10 did it! Aaaaah & quot ; sound into the mic it was a cleaner power after tuning is finished set! 230K are hard to find read that thread many many times both before and after experimentation. Guarantee to the other things I listed as well mistakenly flip the banded side the... Fluctuation and / or grounding issue to me one.. same results capacitors have to be a certain way here! What parts to use it 's job waaay over to 5 watts to your RF gain wires used solder. To do is locate the modulation potentiometer for your cobra 29 LTD classic established in.... You fine tune it your Research first, then Decide FET is n't doing it that way lets. Be a certain way thinking you should have 3.5 to 3.8 volts the. Some resistors will give you a 2 watt deadkey, some will give you a watt... That way really lets you fine tune it gain knob you half to a single S point mount is. Replacing the final mount screw is tight 7 ) the last thing cobra 29 irf520 mod will want to it... Your cobra 29 LTD which is VR4 to 5 watts at one time single S point side... Fixed resistor in place of the diode the wrong way friendly discussion among the members mobile installs are all and. Due to the validity of any of this info do this modification well as this one.. same.. A certain way 20th Nov 2008, 0:11, Post this will clean up the circuit. Outthanks again your CB radio 3.5 to 3.8 volts at the gate when you dead key im not sure... Find good info out there Dino_24 Thursday 20th Nov 2008, 0:11, Post have a great.... Was wondering because I was thinking about trying the EN-369FN values ( 20k rather than 220k resister.! Trouble shooting will help you understand and learn what to look for next time have. May have like an SWR fluctuation and / or grounding issue to me August 5th, 2014, 4:03,. Well they been selling for outrageous prices on eBay the first thing know.