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cobra 19 upgrade
- Thread starter blaze09
- Start date
here is not much that can be done with those little dudes, they are what they are. There is some slight tune up work that can be done to get a touch more modulation and swing. If the finals are old style you cannot just "swap in" mosfets. You would have to re-work other parts/sections of the radio to match up with mosfets. Best bet would be to talk to a trusted tech and see what can be done. I would up-grade to the Cobra 25 size chasis, the mods for them are endless.
Here is all that cb tricks has http://cbtricks.com/radios/cobra/19dxiii/index.htm
Here is all that cb tricks has http://cbtricks.com/radios/cobra/19dxiii/index.htm
Those 19s are just cheap low budget radios that will work OK but will never scream. A Cobra 21 LTD can be modded to talk great but anything less is throwing good money after bad.
If it ain't broke, don't fix it.
Putting time and money into these Cobra 19III would be better spent on other used radio's you could get on eBay if money matters. I just gave mine away. They are OK for people who are not into CB's and just want to talk to someone who is right in front of them so you can max the squelch. They receive pretty good but all the hash and scratch is overwhelming you have to squelch them all the way because the interference is obnoxious and there is nothing special in the audio either! Not trying to knock your radio but they are just not worth trying.
taken from CB Tips and Tricks
Cobra 19 Plus, 19 DX, 19 Ultra (and other brand/models with same chassis):
Supertune: Replace the final with a 2SC1969 unit. Solder a jumper across the diode going from the Audio Transformer to the Driver and Final (this may cause receive distortion at high volumes, remove jumper if it does). Solder a jumper across the resistor going from the base of the Final to the Driver. If a diode has been cut for modulation, solder it back together, or replace it. Adjust the modulation control POT (VR) for 100% modulation (usually between 1/4 to 3/4 way open). Tune output coils for best swing, using a loud, steady "aaaaah" sound into the mic. Note: These radios are superb for clarity of modulation, even on the stock mic.
you could even take the time to install an IRF520 and maybe go for even more out put...
that being said I would not even bother... the BEST upgrade is a new radio
Cobra 19 Plus, 19 DX, 19 Ultra (and other brand/models with same chassis):
Supertune: Replace the final with a 2SC1969 unit. Solder a jumper across the diode going from the Audio Transformer to the Driver and Final (this may cause receive distortion at high volumes, remove jumper if it does). Solder a jumper across the resistor going from the base of the Final to the Driver. If a diode has been cut for modulation, solder it back together, or replace it. Adjust the modulation control POT (VR) for 100% modulation (usually between 1/4 to 3/4 way open). Tune output coils for best swing, using a loud, steady "aaaaah" sound into the mic. Note: These radios are superb for clarity of modulation, even on the stock mic.
you could even take the time to install an IRF520 and maybe go for even more out put...
that being said I would not even bother... the BEST upgrade is a new radio
I need a direct answer or explanation ect on a cobra 19 dx just the plane Jane 19 dx made in the 1990,s.
I can build any type of swing kit I need I'm having trouble trying to locate a proper spot where the 12 volts goes to the driver final or can I install my homebrew kit on one leg between it and the circuit board ? Please and thank you to whomever responds to my post I'm polite ahead of time
I can build any type of swing kit I need I'm having trouble trying to locate a proper spot where the 12 volts goes to the driver final or can I install my homebrew kit on one leg between it and the circuit board ? Please and thank you to whomever responds to my post I'm polite ahead of time
Tricky part is to find a spot to sever the foil trace that feeds power to the driver transistor's collector choke. Some radios would have only one bypass disc capacitor connected where the driver and final chokes were connected together. When that happens, you have to provide a separate .01 disc cap to ground on the cold end of the driver collector choke.
Can't say we ever did that job to that model. Finding somewhere to put an additional knob sounds like a challenge.
That model was made by more than one vendor, so just finding any tech data for the production version you have is an iffy proposition.
Identifying the choke coil connected to the center pin of the driver transistor is the starting point, and unhooking the 'cold' side of the choke opposite the end connected to the driver transistor's collector is what you'll need to do.
It's the same change to the radio that removing the driver's jumper wire does for a Cobra 29. They just didn't make it as easy on this model.
73
Can't say we ever did that job to that model. Finding somewhere to put an additional knob sounds like a challenge.
That model was made by more than one vendor, so just finding any tech data for the production version you have is an iffy proposition.
Identifying the choke coil connected to the center pin of the driver transistor is the starting point, and unhooking the 'cold' side of the choke opposite the end connected to the driver transistor's collector is what you'll need to do.
It's the same change to the radio that removing the driver's jumper wire does for a Cobra 29. They just didn't make it as easy on this model.
73
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