Dynascan Cobra 29 - 23 channel

[KK4JW]

Picked up an absolutely beautiful Dynascan Cobra 29, and I'd like to do some tinkering to get it to perform a little better than what it does. It appears to be completely stock and untouched inside.

I've read about swapping C69, and bypassing R97 to get more audio to the preamp. I've also seen where D24 appears to be the AMC limiter. I really do not want to clip the limiter, but I do want to bring the audio up some and get a little more output from the rig. I DO have decent test equipment available.

Anyone have a list of the VR adjustments?

 

[Crawdad]

A very cool find!
Probably overdue for a new set of electrolytic capacitors. IMO clipping the modulation limiter would not be a good choice. Why butcher a classic that has all the modulation you need already??

Have you checked CBTricks for tuning info?

7 3

 

[KK4JW]

A very cool find!
Probably overdue for a new set of electrolytic capacitors. IMO clipping the modulation limiter would not be a good choice. Why butcher a classic that has all the modulation you need already??

Have you checked CBTricks for tuning info?

7 3

Yeah, I'm not clipping the AMC. I did look at CBTricks, but found little information about actual adjustments. I'll go back and look again though just to make sure.

 

[midnight special]

back in the day we would put a power mike on it my choice was a turner +3

 

[Transresistor]

Send me an email address and I will send you a SM with everything.

 

[nomadradio]

If memory serves, the AMC on that radio was a retrofit. When that model first hit the market, a limiter hadn't yet been required. Some time around 1974 a limiter got grafted onto the radio's audio circuit. Seems to me it worked by pumping positive voltage into the emitter of the mike amp transistor. This is a lame way to reduce the gain of an amplifier transistor, and didn't sound all that smooth. Fortunately every customer wanted it disabled, so it was no big deal. The 40-channel radios were all designed from the ground up to include the AMC function. The practice of placing a NPN transistor's collector onto the incoming audio, emitter grounded and base voltage from rectified audio pretty well took over across brands.

73