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Is the en1230 needed?

Oldtimer

Active Member
May 20, 2008
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Stuart Florida
I did the erf2030 & en1230 mod to my cobra 29 wx/st/nw.
I get around 10-12 watts.
A friend had his cobra 25 done at a shop and gets around 30 watts.
I looked inside his 25 and noticed the en1230 wasn't there. the stock
resistor at r-56 was still there.
Do you really need the en1230?
Thanks
GOD BLESS
 

1230 installed

I have also noticed a cobra 29 from clays radio shop that has the final changed to the fet but no companion part installed. that radio would swing to 40 watts. I have done several of these mods but have never had quite that type of pep. Just wondering if someone may know a different version of the mod. The one that freecell references to is the only one that I have seen.
 
ive seen this also and it leads to trouble unless they make a companion part and put it on thr back side of the board. and if it was done by clays i would say unless one of his yahooos did it it has a part hidden somewhere. tj's cb shop in whithfield virginia doesit sortof likethis but changes the 22ohm with like a 220k and diode on back side so no one notices that dont know what to look for.
 
The Facts: From Dodgem's CB Radio Workbench

The ERF2030 is a replacement for a 2sc1969

The EN1230 is a "Swing Kit".

The word "Companion" just sells itself better than just saying Swing Kit.

I build my own Companion parts here in the shop and I have actually improved the design off the original EKL part for better performance over the factory part. The factory will only offer you what "works" I offer a better option here LOL.



BUMP-BUMP !
Dodgem
DM CB Radio
Indian Head, Maryland
 
Some radios have been known to do an average "first-key" of 35 to 40 watts, but, not all radios have the same output, regardless if they are the same radio or not. In most cases the radios that are showing a 40 watt or more PEP, has very little to do with the Final upgrade. I've installed a few hundred of these MosFet upgrades and I've never been impressed with the outcome on average, but, it does work in some radios like it claims. I have resorted back to the IRF520 with my hand-soldered "companion" part and I've been super happy from there on.

I have also noticed a cobra 29 from clays radio shop that has the final changed to the fet but no companion part installed. that radio would swing to 40 watts. I have done several of these mods but have never had quite that type of pep. Just wondering if someone may know a different version of the mod. The one that freecell references to is the only one that I have seen.
 
I read this thread and wondered my self if the en-1230 is needed, so I conducted an experiment.

I did the mod everything but the en-1230.

Conclusion. It works, for a few minutes until the final dies. Before fine tuning, just by changing the final, and removing the specific parts, it would dead key 15 watts, and swing over 30 pep.

I was impressed, until the wattage it was doing dropped, and final got really hot, and died.

So I would say the en-1230 is necessary, or some other paring of components that accomplishes the same thing is added.
 
Sorry for the double post, but I wanted to add that, the EN-1230 is used to bias the ERF2030 properly. Without it you will basically over bias the final.
 
So what can be used instead of the end 1230 ? It's not being made and it's more rare than a hens tooth. Does anyone or is anyone willing to share there recipe for putting one together using what diode n what size transistors..?? !! I'm searching n if I can figure it out I will definitely be back to share all without charging. !! Thanks.
 
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Or...

Build Your Own...
upload_2020-11-23_8-50-52.png

I'm sure others will come in with their own ideas and methods...

But to help you with the above, Many just remove R123 - which is your prerogative, but to me it also plays an important role in how much Gate Drive and Bias - if not kept separate - will eventually destroy the IRF520.

Now, you may want to adjust values to meet the power levels you want;

You cannot do a JP36 MOD and also this MOD and expect both to work using "specific" values shown - it may work, or not - you will need to make the EN-1230 part provide the Gate the Bias as needed, change the resistors of the EN1230 to help with this - else you may need to apply other methods shown further below.
  • the above shows a 1N4148, and 470 ohm - you keep the diode, but MODIFY the resistor from 390 to a high as 680 ohms to lower, or raise - BIAS power.

The EN-1230's 3.3K can go as low as 1.5K to as high as 3.3K - but affects the OVERALL level of signal DRIVE present in the line that goes to the final.

Note the "R123" - it's important - this area many techs just remove and jumper, which again, you choose your poison, but really you need to keep it in to prevent another problem that tends to creep into this.

If you want to use Variable power to adjust for amp drive, then the values to replace the EN1230 used for the above will be different. Use the higher (greater ohmic resistance) values to allow more RF signal to apply and keep the MOSFET working.

IT's when you drop the dead key too low, does the MOSFET have trouble working linearly let alone properly.

So R123, if jumpered, exposes the Gate to potentially higher drive currents and voltages that can exceed the parts' Gate Drive Rated limits - R123 installed, reduces / impedes the RF signal - so to offset the Drive to Signal ratios, especially on low power levels - install a small value Disc Cap across R123 as needed to allow more RF signal to arrive to keep the MOSFET on.

To adjust the carrier- you have to modify the EN1230 part - it's better to change the 3.3K Resistor (shown in position piggy-backing the 1N4148 and 470 ohm) to higher or lower values to offset the VOLTAGE you'll need to keep the part working on low, and R123 as needed to keep the MOSFET from blowing up if you need / send the Gate full RF power - as it (RF power) and the Gate Rectified Bias from the EN1230 can raise the level of power applied to the Gate and destroy the MOSFET.

The Range of Adjustment is the problem, and R123 is needed to help with this. It' is better to lessen the GATEs' DC voltage (from the EN1230) by increasing the R123 resistor value - and let RF from DRIVER go into MOSFET across the Cap - in enough level to offset.

There is another reason for R123 - is;

IF your variable power mod can't go as low as you want - you may need to install a 10K "Tickler" resistor to apply a trickle voltage from the TX transistor located close by - Locate JP29 and positive side of C116, solder one leg of the 10K there, with the other leg to the R123 side of R56 to help keep the MOSFET on when driven in low power mode.

If you want a lot of variable RF power (like Low 1.5 watt to high 20W) find another method, this is only for 4 watt radios being "refurbed" with the IRF520 (or Equivalent) MOSFET
upload_2020-11-23_9-27-37.png
 

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