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I've recently acquired an Icom IC-745 and I'm unclear on how it's supposed
to work in CW mode. It does receive in SSB and AM, so in general the receiver appears to work. When I press the 'mode' button to get it to CW mode, however, it's just... silent Joel- As others have already mentioned, the radio might have had the CW filter removed without replacing a jumper that was removed when the filter was first installed. Someone else may have mentioned the possibility of a defective diode in the filter-selection circuit. It is also possible that a crystal is bad in the circuit where USB/LSB/CW are selected. Newer radios use signals derived from the Phase-Locked Loop oscillator, but older ones had separate crystals for each mode. I don't know where the IC-745 falls. If you have another radio to tune to the frequencies of these crystals, you should be able to tell if one is not working. All three should be within about 3 KHz of each other. 73, Fred, K4DII |
#3
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Be sure the NARROW filter selection is not depressed. I have a 745
also. Great rig! Steve On 26 Nov 2004 18:14:40 GMT, unicate (Fred McKenzie) wrote: I've recently acquired an Icom IC-745 and I'm unclear on how it's supposed to work in CW mode. It does receive in SSB and AM, so in general the receiver appears to work. When I press the 'mode' button to get it to CW mode, however, it's just... silent Joel- As others have already mentioned, the radio might have had the CW filter removed without replacing a jumper that was removed when the filter was first installed. Someone else may have mentioned the possibility of a defective diode in the filter-selection circuit. It is also possible that a crystal is bad in the circuit where USB/LSB/CW are selected. Newer radios use signals derived from the Phase-Locked Loop oscillator, but older ones had separate crystals for each mode. I don't know where the IC-745 falls. If you have another radio to tune to the frequencies of these crystals, you should be able to tell if one is not working. All three should be within about 3 KHz of each other. 73, Fred, K4DII |
#4
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Be sure the NARROW filter selection is not depressed. I have a 745
also. Great rig! Steve On 26 Nov 2004 18:14:40 GMT, unicate (Fred McKenzie) wrote: I've recently acquired an Icom IC-745 and I'm unclear on how it's supposed to work in CW mode. It does receive in SSB and AM, so in general the receiver appears to work. When I press the 'mode' button to get it to CW mode, however, it's just... silent Joel- As others have already mentioned, the radio might have had the CW filter removed without replacing a jumper that was removed when the filter was first installed. Someone else may have mentioned the possibility of a defective diode in the filter-selection circuit. It is also possible that a crystal is bad in the circuit where USB/LSB/CW are selected. Newer radios use signals derived from the Phase-Locked Loop oscillator, but older ones had separate crystals for each mode. I don't know where the IC-745 falls. If you have another radio to tune to the frequencies of these crystals, you should be able to tell if one is not working. All three should be within about 3 KHz of each other. 73, Fred, K4DII |
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