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Repair Dragon CB-240N

thelonegunman

Member
Nov 19, 2011
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Hi everyone!! I open this post to see if anyone can help me, although I fear it will be difficult. Excuse my writing, I am writing to you from Spain.

I started as a child with the CB, emulating my brother, and with the little money I had, I was able to acquire an inexpensive station, a Dragon CB-240N, which shares a circuit with the Memory 8012. Attached diagram.

We had a faulty stationary meter and used the equipment with an uncoupled antenna. I have rescued the equipment recently and it has very little power output, barely 2W, having at that time raised it to about 8W. I sense that it has deteriorated endings.

Years ago, following a tutorial, I converted a Saturn 3900 to mosfet, using the IRF520s.

Without a tutorial or instructions, I am unable to make a modification. I have knowledge in electronics, but not that much. I would like to repair the equipment and give it a little more power, without exaggeration. I have in my possession a 2SC2166, two 2SC2312 and several IRF520.

Would it be very difficult to modify my scheme to be able to use the two transistors, and gain a little power? or, failing that, use the 2SC2166 as the driver and the IRF520 as the final one. I am afraid that both the driver and the end of my station are damaged.

Thank you very much for reading the post and for your help.
 

Attachments

  • memory-8012-988028.pdf
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  • Schematic_Dragon_CB240N.pdf
    299.7 KB · Views: 6
Last edited:

Hello, i have check the power with a watt-metter only. The station have tunned up to 8W years ago, but after use it with a de-tuned antenna, the actual power is around 2W

Yes, i have a legit 2312 and 2166, from the Saturn 3900 converted to Mosfet. In good condition.
 
2312 and 2166 are not multi emitter devices, so can't deteriorate.
There can be many more causes of this power loss. I would take rf probe and measure TX path, easy to spot where power disappear.
I assume you measure it on dummy load?
 
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Yes, with dummy load, and also with antenna. Where another station gives 8W, this one only gives 2W.

I have no equipment to measure RF, just a multimeter.
 

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