Good day people.
I have this vintage TRC48 radio. It has a lot of sentimental value and I would love to get it running properly. So here goes.
This radio works great except it has sporatic loss of Am and USB, TX and RX on channels 4,8,16,20,and 23.
During research I found that crystal 14.947 is common to these channels and replaced it, still the same issue.
I have eliminated the possibility of a channel selector issue, a cold solder joint or broken trace.
Interesting points:
a) If you probe the board with a VOM, you may probe a random component and all of a sudden it will start working again on the channels listed above.
b) When it works, it may work for a couple of days and then all of a sudden you will slowly see the RX and TX getting lower and lower and eventually stop. It just doesn't stop all of a sudden. I think this may be a very good hint as to what may be the problem
c) When it acts up, the radio tried to transmit. (You can hear the relay click when the mic is pressed) but no TX power.
d) This issue is only with the AM + USB channels 4,8,16,20,and 23. All other Channels work great..
I know the value of this radio is very low but I have had it for 30 years and it is part of me.
Any techical advice would be greatly appreciated. I have checked all the obvious and am quite sure it is a weak component issue. Question is which one.
I have the original owners manual which includes the block diagram and schematic if you have any questions related to it.
Thanks guys for any support you can offer.
Jim (Mork)
I have this vintage TRC48 radio. It has a lot of sentimental value and I would love to get it running properly. So here goes.
This radio works great except it has sporatic loss of Am and USB, TX and RX on channels 4,8,16,20,and 23.
During research I found that crystal 14.947 is common to these channels and replaced it, still the same issue.
I have eliminated the possibility of a channel selector issue, a cold solder joint or broken trace.
Interesting points:
a) If you probe the board with a VOM, you may probe a random component and all of a sudden it will start working again on the channels listed above.
b) When it works, it may work for a couple of days and then all of a sudden you will slowly see the RX and TX getting lower and lower and eventually stop. It just doesn't stop all of a sudden. I think this may be a very good hint as to what may be the problem
c) When it acts up, the radio tried to transmit. (You can hear the relay click when the mic is pressed) but no TX power.
d) This issue is only with the AM + USB channels 4,8,16,20,and 23. All other Channels work great..
I know the value of this radio is very low but I have had it for 30 years and it is part of me.
Any techical advice would be greatly appreciated. I have checked all the obvious and am quite sure it is a weak component issue. Question is which one.
I have the original owners manual which includes the block diagram and schematic if you have any questions related to it.
Thanks guys for any support you can offer.
Jim (Mork)
