Insert replay with box, the screen has a normal playback symbol and tape count, according to the machine system control circuit and mechanical tape work essentially normal. Press the VTR + / TV key, VTR + indicator, still no silent monitor, change the rf output to single frequency/video output, there is the normal color pattern on the monitor and the audio signal, restore the rf output connection, will see the back plate/TEST switch to the TEST position, film and television is still no TEST signal display on the screen, to show that the fault VTR12V output power control or frequency modulator circuits. Rf modulator with a multimeter to check 5 feet (+ BS12V) no voltage, check VTR12V output switch tube Q3007 sb641 (2), measured Vb1, Ve1 to 2 V, Vc 1.6 V to 0.5 V (normal should be 12 V). Welding Q3007 examination revealed under b - e electrode has been damaged, open 5 feet caused by radio frequency modulator + 12 v voltage loss, BS modulator integrated block IC1 / AN3110 for work. Replace Q3007 (also available domestic cg120 instead of 3) after the machine back to normal.EE7service manual download site