Hello,Cobra 25 LTD ST, I have 10 Volts at TP2, where I am to turn it down to 3.5 Volts, the radio is making a Pulsing humming noise, and blew up 3 Capacitors as I wanted to diagnose the problem. Has any body had this problem, I replace both Transformers in the CB, and the CB keeps knocking my reset switch on my Power Supply for the radio.
I am repairing a no receive and no transmit in the radio. This is what I have done.
1. Unsoldered the Final and Driver,,,,No Difference
2. Unsoldered the Audio Amplifier, No Difference
3. Changed the C125, 2 Watt, 3.9 ohm Resistor, Between Ext speaker and PA connections, No Difference
When it does the humming, you can see the light pulsating with the humming noise.
Any ideas would be a great appreciation in advance. Thanks to all who try to figure this one out, I am stumped.
THANK YOU, Mark KB9GTB Voltage at the 2 Reverse polarity Diodes, as I have around 13.2 Volts at both Diodes, that does not seems correct??, I think it should be 13 at the first one and around 6 or so Volts at the second one, need to see what is in between these 2 diodes,
I am repairing a no receive and no transmit in the radio. This is what I have done.
1. Unsoldered the Final and Driver,,,,No Difference
2. Unsoldered the Audio Amplifier, No Difference
3. Changed the C125, 2 Watt, 3.9 ohm Resistor, Between Ext speaker and PA connections, No Difference
When it does the humming, you can see the light pulsating with the humming noise.
Any ideas would be a great appreciation in advance. Thanks to all who try to figure this one out, I am stumped.
THANK YOU, Mark KB9GTB Voltage at the 2 Reverse polarity Diodes, as I have around 13.2 Volts at both Diodes, that does not seems correct??, I think it should be 13 at the first one and around 6 or so Volts at the second one, need to see what is in between these 2 diodes,