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TR7 tone

Jim Harris All Messages By This Member #82444 Hi once again. I am back trouble shooting the TR7 with what I hope is the last problem. When I switch the?mode switch?to CW I get a 1800 cycle tone in the receiver that is over S9 in strength. If you change the frequency this tone does not change at all. I have a Version 2, 2nd I.F/Audio board. I have not found an explanation?of how the CW operation works but maybe the problem is on that board. Anyone got any ideas? All suggestions appreciated and welcomed. Thank you, Jim VE1RB
Jim Shorney All Messages By This Member #82445 Yes, you want to look at the 2nd IF/Audio board. CW operation is described towards the end of the text in section 2-11 of the service manual. In short the CW transmit carrier is generated by a crystal oscillator that is offset nominally 800 Hz from the dial frequency. The oscillator is keyed by Q1103 on this board. More info on the oscillator is here: On Sat, 1 Feb 2025 14:17:50 -0400 "Jim Harris via groups.io" <radiove1rb@...> wrote: Hi once again. I am back trouble shooting the TR7 with what I hope is the last problem. When I switch the mode switch to CW I get a 1800 cycle tone in the receiver that is over S9 in strength. If you change the frequency this tone does not change at all. I have a Version 2, 2nd I.F/Audio board. I have not found an explanation of how the CW operation works but maybe the problem is on that board. Anyone got any ideas? All suggestions appreciated and welcomed. Thank you, Jim VE1RB -- 73 -Jim NU0C
Jim Harris All Messages By This Member #82451 Thanks Jim for the info and I will try and get back at it tomorrow.? 73, Jim VE1RB toggle quoted message Show quoted text On Sat, Feb 1, 2025 at 2:38?PM Jim Shorney via <jimNU0C=[email protected]> wrote: Yes, you want to look at the 2nd IF/Audio board. CW operation is described towards the end of the text in section 2-11 of the service manual. In short the CW transmit carrier is generated by a crystal oscillator that is offset nominally 800 Hz from the dial frequency. The oscillator is keyed by Q1103 on this board. More info on the oscillator is here: On Sat, 1 Feb 2025 14:17:50 -0400 "Jim Harris via " <radiove1rb=[email protected]> wrote: > Hi once again. I am back trouble shooting the TR7 with what I hope is the > last problem. When I switch the mode switch to CW I get a 1800 cycle tone > in the receiver that is over S9 in strength. If you change the frequency > this tone does not change at all. I have a Version 2, 2nd I.F/Audio board. > I have not found an explanation of how the CW operation works but maybe the > problem is on that board. Anyone got any ideas? All suggestions appreciated > and welcomed. > Thank you, Jim VE1RB -- 73 -Jim NU0C
Jim Harris All Messages By This Member #82567 开云体育 Have been working on the TR7 CW issue and today I changed the switching transistor that turns on the 10 volts and off. Before I changed the PNP transistor when the key is up it showed 1.77 volts and now it shows 0.8 volts but that seems to be enough to keep the crystal oscillator running. Got to think this over more and try something else. Any idea and or suggestions welcomed. 73, Jim VE1RB On 2025-02-01 16:33, Jim Harris via groups.io wrote: toggle quoted message Show quoted text Thanks Jim for the info and I will try and get back at it tomorrow.? 73, Jim VE1RB On Sat, Feb 1, 2025 at 2:38?PM Jim Shorney via <jimNU0C=[email protected]> wrote: Yes, you want to look at the 2nd IF/Audio board. CW operation is described towards the end of the text in section 2-11 of the service manual. In short the CW transmit carrier is generated by a crystal oscillator that is offset nominally 800 Hz from the dial frequency. The oscillator is keyed by Q1103 on this board. More info on the oscillator is here: On Sat, 1 Feb 2025 14:17:50 -0400 "Jim Harris via " <radiove1rb=[email protected]> wrote: > Hi once again. I am back trouble shooting the TR7 with what I hope is the > last problem. When I switch the mode switch to CW I get a 1800 cycle tone > in the receiver that is over S9 in strength. If you change the frequency > this tone does not change at all. I have a Version 2, 2nd I.F/Audio board. > I have not found an explanation of how the CW operation works but maybe the > problem is on that board. Anyone got any ideas? All suggestions appreciated > and welcomed. > Thank you, Jim VE1RB -- 73 -Jim NU0C
Jim Harris All Messages By This Member #83140 I am still fighting with the CW tone in the receiver as soon as I set the mode switch to CW. I changed Q1103 three times and no change so assuming that the 5 volts or so on the collector must be coming from somewhere else. I am wondering if many CR111 might be bad? Looks like? Pin switching diode. Any thoughts why I have that voltage on the collector? Any suggestions are welcome and appreciated. Thanks, Jim VE1RB toggle quoted message Show quoted text On 2025-02-01 14:17, Jim Harris wrote: Hi once again. I am back trouble shooting the TR7 with what I hope is the last problem. When I switch the?mode switch?to CW I get a 1800 cycle tone in the receiver that is over S9 in strength. If you change the frequency this tone does not change at all. I have a Version 2, 2nd I.F/Audio board. I have not found an explanation?of how the CW operation works but maybe the problem is on that board. Anyone got any ideas? All suggestions appreciated and welcomed. Thank you, Jim VE1RB
Craig W8CS All Messages By This Member #83144 Any chance that you're actually transmitting when you go into CW mode? ? I had this issue many moons ago, lightning hit shorted out a disc cap across the key jack input.? -- Craig/W8CS Greenville, SC
Jim Harris All Messages By This Member #83154 Thanks Craig and no transmitting as the relay does not change but do appreciate the tip.? Jim VE1RB toggle quoted message Show quoted text On Tue, Feb 25, 2025 at 12:41?PM Craig W8CS via <craig_severson=[email protected]> wrote: Any chance that you're actually transmitting when you go into CW mode? ? I had this issue many moons ago, lightning hit shorted out a disc cap across the key jack input.? -- Craig/W8CS Greenville, SC
Jim Shorney All Messages By This Member #83157 There is no CR111. The part numbers are all 4 digit. CR1111 feeds a sample of the CW signal to the product detector so you can hear the sidetone. You can see if it is the fault by removing it from the circuit and checking your voltage again. Lifting one end of R1152 should do the job. It is recommended that you actually test components to see if they are faulty rather than just replacing them and hoping for the best. I would also check to see if you have a low impedance path to ground on pin 11/7 (KEY) or the base of Q1103 that would turn Q1103 partially on. On Tue, 25 Feb 2025 11:30:02 -0400 "Jim Harris via groups.io" <radiove1rb@...> wrote: I am still fighting with the CW tone in the receiver as soon as I set the mode switch to CW. I changed Q1103 three times and no change so assuming that the 5 volts or so on the collector must be coming from somewhere else. I am wondering if many CR111 might be bad? Looks like? Pin switching diode. Any thoughts why I have that voltage on the collector? Any suggestions are welcome and appreciated. Thanks, -- 73 -Jim NU0C

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