New Victim! (project) Realistic Navaho TRC-457

[nomadradio]

Do you have any idea what would cause this.

Yep. Turning up the AM modulation limiter. This radio has a modulation transformer for AM transmit, just like a Cobra 29. It feeds peak voltages into the final that stay below the capacitor's 25-Volt rating. Turning it up now causes voltages that exceed the rating to reach this part, and it breaks down from overvoltage.

It should be replaced with a 50-Volt part (better) or at least a 35-Volt rated cap. Installing a 25-Volt cap will produce a repeat performance.

73

 

[doffo]

Yep. Turning up the AM modulation limiter. This radio has a modulation transformer for AM transmit, just like a Cobra 29. It feeds peak voltages into the final that stay below the capacitor's 25-Volt rating. Turning it up now causes voltages that exceed the rating to reach this part, and it breaks down from overvoltage.

It should be replaced with a 50-Volt part (better) or at least a 35-Volt rated cap. Installing a 25-Volt cap will produce a repeat performance.

73

I struggle to explain things. You do a fantastic job. Thanks.

 

[nomadradio]

Just takes practice. Way too many of these little explanations are distilled down from an explanation repeated to a hundred customers, each with the same repair. That kind of repetition eventually gets the story shrunk down to the essentials.

73