Post by Deleted on Oct 27, 2017 4:17:47 GMT -5
Radio loads well on all bands but 80 and 160. I cannot get the plate current to dip lower than about 390ma on 80 or 160M.
I would like to load to 330mA to then adjust the Mod Bias but I cant reach that lower level of plate current.
I have pulled the "special tree cap" and cleaned. Back in circuit the capacitance as measure on the RF output and ground appear in the acceptable range...1170pf with Aux. Load in 10 position to 4280pf in 0 position. Steps are about 300pf between each Aux. switch position so that seems OK. I changed the 40M and 80M padding caps to 2kv rated....I checked the one 300pf/1200V mica cap and it is reading in its tolerance range for capacitance
But still, cant adjust the plate to get it below 390-400mA....this is in cw mode when tuning, also all into a 50 Ohm dummy load (pure resistive).
Any thoughts and suggestions appreciated.
Please help.
Thanks!
I didn't find the right solution from the Internet.
References www.antiqueradios.com/forums/viewtopic.php?f=5&t=319131
Mobile App Launch
I would like to load to 330mA to then adjust the Mod Bias but I cant reach that lower level of plate current.
I have pulled the "special tree cap" and cleaned. Back in circuit the capacitance as measure on the RF output and ground appear in the acceptable range...1170pf with Aux. Load in 10 position to 4280pf in 0 position. Steps are about 300pf between each Aux. switch position so that seems OK. I changed the 40M and 80M padding caps to 2kv rated....I checked the one 300pf/1200V mica cap and it is reading in its tolerance range for capacitance
But still, cant adjust the plate to get it below 390-400mA....this is in cw mode when tuning, also all into a 50 Ohm dummy load (pure resistive).
Any thoughts and suggestions appreciated.
Please help.
Thanks!
I didn't find the right solution from the Internet.
References www.antiqueradios.com/forums/viewtopic.php?f=5&t=319131
Mobile App Launch