Monstermug
Active member
Got a WG6100 Deflection board recently. Was told that it had two faulty rectifying diodes and a blown fuse.
Sure enough 1 of the full wave rectifying diodes at D100-103 faulty. I replaced all three as well as the fuse at F101 with 5A SB fuse and at the same time changed C100-101 as well.
Poked around testing a few critical components and deemed it okay to run a full test.
Powered applied and got a blank screen, spot killer came on, had a small distorted image in bottom left hand corner before fire was shooting out the back of the cab.
The LV2000 was on fire!
Quickly blew it out and went and ordered a new LV2000 as I didn't have any spare. I guess when the rectifying diodes blew fuse F101 it also shorted something on the LV2000. I didn't think to test this as they say this never goes bad! (I think they offer a replacement if it does?)
So replacement LV2000 came today. Quickly installed. Poked around a bit more to make sure that nothing else was causing the LV2000 to smoke (there wasn't) and ran another full test... This time at the ready to blow out the fire.
Sadly no more fires. Spot killer came on. Deflection chatter. Some image on the screen which looks like speckled dots rather than vectors. Weird??? Never seen that before.
Now the next few hours was spent checking every component on the board. Everything checked out good!
Something had to be causing this. Normally if everything is good, there must be a problem with the spot killer circuit. Had a look at that and at first everything tested good. I wasn't happy. Took out the schematics and found that someone had replaced a 2N3906 transistor at Q800 with a 127-001 (MPSA06)! Similar but not quite the same it seems! Decided just to change out all the 127-001's while I was at it. None of them tested bad.
Also decided to replace an oversized wire wound resistor at R701 with a normal sized one. Probably was okay but I like to be neat.
Plugged it back in and got a beautiful picture!
Gave the board a good clean and now it's ready to back into it's old home.
Sure enough 1 of the full wave rectifying diodes at D100-103 faulty. I replaced all three as well as the fuse at F101 with 5A SB fuse and at the same time changed C100-101 as well.
Poked around testing a few critical components and deemed it okay to run a full test.
Powered applied and got a blank screen, spot killer came on, had a small distorted image in bottom left hand corner before fire was shooting out the back of the cab.
The LV2000 was on fire!
Quickly blew it out and went and ordered a new LV2000 as I didn't have any spare. I guess when the rectifying diodes blew fuse F101 it also shorted something on the LV2000. I didn't think to test this as they say this never goes bad! (I think they offer a replacement if it does?)
So replacement LV2000 came today. Quickly installed. Poked around a bit more to make sure that nothing else was causing the LV2000 to smoke (there wasn't) and ran another full test... This time at the ready to blow out the fire.
Sadly no more fires. Spot killer came on. Deflection chatter. Some image on the screen which looks like speckled dots rather than vectors. Weird??? Never seen that before.
Now the next few hours was spent checking every component on the board. Everything checked out good!
Something had to be causing this. Normally if everything is good, there must be a problem with the spot killer circuit. Had a look at that and at first everything tested good. I wasn't happy. Took out the schematics and found that someone had replaced a 2N3906 transistor at Q800 with a 127-001 (MPSA06)! Similar but not quite the same it seems! Decided just to change out all the 127-001's while I was at it. None of them tested bad.
Also decided to replace an oversized wire wound resistor at R701 with a normal sized one. Probably was okay but I like to be neat.
Plugged it back in and got a beautiful picture!
Gave the board a good clean and now it's ready to back into it's old home.
