Cobra 29 R103 & R104 getting hot, burnt

[Chris Lawrence]

Fairly new Cobra 29 Chrome. The channel display was going on and off. Opened radio. R103 was smoked. Replaced and it fixed issue.

R103 (and R104) get extremely hot to the touch when keying up. They are 1 & 2 watt resistors so I expect they get hot but, they shouldn’t burn up. They only get hot when keying up.

What should I be looking for? What should I check?

 

[BayouRadioAmplifier]

hmmmm. just looked at schematic.
that 15 ohm resistor that burned up is R104.
It is at the input of the 8 V regulator circuit. (TR23)

measure the voltage at emmiter of TR23 in tx and rx

measure the voltage across R104
compute the power there. V squared divided by 15

maybe put a two watt resistor for R104