Hello everyone, I'm referring to this post, the only one I've found, to ask and perhaps share my experiences, I'll get to the point. The instrument in question, E4406A, turns on abnormally. The first startup was successful but disconnecting one or more cards, RF IF SINCH. I replaced the two 100k resistors on the fan board, thanks to a suggestion from the forum. Before replacing the resistors, I saw two red LEDs light up on the fan board. After installing the two new resistors, the red LEDs remain off. I have checked all the output capacitors of the power supply, ALL GOOD. WHAT HAPPENS: IF I TRY TO TURN ON THE INSTRUMENT without the RF IF and SINCH cards, it turns on and after a while, about 5 seconds, the screen remains white without booting.
However, if I try to turn it on, by turning on I mean pressing the button on the front, the instrument DOES NOT start, the fans do not start and the green LED on the front indicates an attempt to turn it on but it does not start. Same behavior as the 4 LEDs located behind on the motherboard.
I soldered a series of thin wires onto the power supply outputs and measured the voltages. Voltages present, at least the main ones, and only if I turn it on WITHOUT the cards. I have no idea if it's possible to test the power supply off-site, but I did it anyway. I find the fixed voltage of 15 volts on pin 1 and the remaining voltages are in fact intermittent. maybe without load it will be normal? Who knows more? Thanks