Hi All,
This is a follow-up post of the one called ¡°TR7 suddenly lost power¡±.
To summarize, the PA was fixed, and in CW it generates 150W on 80 and 40 mts, 140W on 20, 40W on 15 and less than 10W on 10 meters, on all modes.
I checked the pin diodes in the HPF, front and rear boards, finding no open or shorted diodes.
The only diode that calls my attention is CR1501, with 600mV on the anode with the equipment on 10mts, receive condition. Based on what I have read, it should not be above 300mV, so I need to replace the diode. As I do not have UM9401s, I understand 1N4007s can be used instead. Is it so?
Something else: there is quite a difference in the SSB and CW output power on 15 and 10 mts. On 15mts, I get 90W on SSB and 40W on CW.? At the beginning, I couldn¡¯t get more than 60W on 40m CW until I adjusted the frequency of the 5.645 KHz CW oscillator to produce a lower pitch sidetone¡ The maximum power happens when the pitch is close to zero Hz. I left it at 300 HZ so I can hear the sidetone. I aligned the 2nd Mixer and got a bit more power, not as much as I expected.
Any ideas?? Thanks in advance.
73 de Raoul CE3RY
