17-05-2022, 06:47 PM
Not a good day.
Amp chip is KA2201, straight forward and I know it works because MW is working.
Other chip is (blank, blank blank) 16pin DIL . That is all I can find about it, no markings at all. But it must work as MW is working.
LW is obviously never going to work with the aerial coil all chopped up. I have tried to identify the connections, to find the broken ends, to establish what the 4 connections do.
But defeated. There are several turns of extremely fine wire cut and displaced. All waxed heavily.
The connections are made with 2, 3 and 4 strands of wire twisted together to the pcb connections, a bit like constructed Litz wire.
The winding is roughly pile wound with more than 1 , 2 or 3 strands wound simultaneously so it is impossible to unwind any part as it is all knotted together. I thought it would be just 2 coils but so far I cannot identify a single winding.
Having tried to find the breaks I now have 11 ends, and none of them give continuity to another. Unbelievable.
So without knowing the circuit I cannot reconstruct a LW coil.
As to the FM VHF that is another unknown. It looks like 2 transistors feeding into the rest of the AM circuit around the chip.
Bit of an impasse.
If all else fails I may construct an AM/FM/DAB chassis to fit inside the radio using the existing control knob positions.
Amp chip is KA2201, straight forward and I know it works because MW is working.
Other chip is (blank, blank blank) 16pin DIL . That is all I can find about it, no markings at all. But it must work as MW is working.
LW is obviously never going to work with the aerial coil all chopped up. I have tried to identify the connections, to find the broken ends, to establish what the 4 connections do.
But defeated. There are several turns of extremely fine wire cut and displaced. All waxed heavily.
The connections are made with 2, 3 and 4 strands of wire twisted together to the pcb connections, a bit like constructed Litz wire.
The winding is roughly pile wound with more than 1 , 2 or 3 strands wound simultaneously so it is impossible to unwind any part as it is all knotted together. I thought it would be just 2 coils but so far I cannot identify a single winding.
Having tried to find the breaks I now have 11 ends, and none of them give continuity to another. Unbelievable.
So without knowing the circuit I cannot reconstruct a LW coil.
As to the FM VHF that is another unknown. It looks like 2 transistors feeding into the rest of the AM circuit around the chip.
Bit of an impasse.
If all else fails I may construct an AM/FM/DAB chassis to fit inside the radio using the existing control knob positions.
Boater Sam.
