I have an Emerson LF320EM4F that seems totally dead. I made some measurements using the the metal tab on the corner of the board as ground. The 21v, 3.3v and 13v lines are all dead.
J145(Reset) Is 2.6v and J171(Protect3) is 0.073v. On CN1001, I get 2.2v. On the Primary side, I get 173.8v at the main filter cap. I've looked the board over for any physical damage and there are three places I've identified. On the secondary, D660 seems to have had it's face blown off.
On the primary side, Q602 also has a chunk of itself missing. Right next to it, C609 has darkened areas to each side of it. I didn't even notice this until I looked at the images I took. I worry that there may be a short in the transformer since this one seems to be an uncommon part, but my understanding is this is rare. After that, I wonder if the transformer isn't being fed properly considering the damage to Q602. I'm not sure either way.
According to a service manual for a very similar TV, the rectifying diodes on the primary side, Q601, Q602, and T601 could be at fault. I don't think the diaodes are the problem considering the measurment on the main filter cap. This makes me think the problem is with the transformer or the damaged Q6o2.
J145(Reset) Is 2.6v and J171(Protect3) is 0.073v. On CN1001, I get 2.2v. On the Primary side, I get 173.8v at the main filter cap. I've looked the board over for any physical damage and there are three places I've identified. On the secondary, D660 seems to have had it's face blown off.
On the primary side, Q602 also has a chunk of itself missing. Right next to it, C609 has darkened areas to each side of it. I didn't even notice this until I looked at the images I took. I worry that there may be a short in the transformer since this one seems to be an uncommon part, but my understanding is this is rare. After that, I wonder if the transformer isn't being fed properly considering the damage to Q602. I'm not sure either way.
According to a service manual for a very similar TV, the rectifying diodes on the primary side, Q601, Q602, and T601 could be at fault. I don't think the diaodes are the problem considering the measurment on the main filter cap. This makes me think the problem is with the transformer or the damaged Q6o2.
Comment