The Electronics Universe
The CB Forum => CB Radio Repair Forum => Topic started by: The Radio Shop on December 14, 2014, 04:46:48 PM
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Here I have a un hacked unmolested TRC-457. This radio is as original as I have seen. I did replace the filter cap on the power supply board to get it to turn on. There is not TX or RX but I have not fully tested the radio yet. All I have done was cleaned the front panel due to heavy nicotine deposits.
I checked the 10.240 on IC7 pin 9 and 10 and it is present. I also checked for frequency on TP-6 and it is there. This leads me to think the PLL is ok but will need further testing.
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Couple more pics
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you may have some 10 volt caps going down on you. right by the relay is a diode and cap 10 volt I believe. they can go bad and kill rx and tx. at least they did on 2 of my old washingtons I refurbed a couple years ago. believe the diode was a zenor if memory serves me right. I think they both are in the same circuit together.
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you may have some 10 volt caps going down on you. right by the relay is a diode and cap 10 volt I believe. they can go bad and kill rx and tx. at least they did on 2 of my old washingtons I refurbed a couple years ago. believe the diode was a zenor if memory serves me right. I think they both are in the same circuit together.
That's a very good diagnosis Sonoma. Those caps can cause lots of issues. Plan is to replace all electrolytic caps and tantalums.
Next step is to check all psu voltages and ripple.