centipede Died :( Help Please

super56k

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Hello again fellas. I've been so busy as of late, but tonight, my original dedicated Centipede died. :( It's an upright, and all it does is the game powers up, you can hear sound and play but the monitor remains black. The Marquee also flickers. I checked all of the fuses and they are all good. My outlet has a steady 122VAC. The AC wires in the cabinet are all black/white, except for the ones going to the monitor and marquee, they are brown/white. The black/white wires come from the line voltage, but the brown/white are somehow tied in the isolation transformer, rectifier and a huge capacitor. See here: http://www.arcade-museum.com/manuals-videogames/C/Centipede.pdf page 40. I think the issue lies here. Any thoughts?
 
sounds like you've got a dead monitor... if you have a digital multimeter and are familiar around a monitor, i'd check the b+ voltage to see if you get anything, and check with a flashlight on the pc board on the monitor to see if the fuse is blown. then you probably want to head on over to the monitor forum with this.
 
When the monitor on my Centipede went out it turned out simply to be a bad connection on the two prong power connector to the monitor. Try wiggling it to see if the monitor comes on. Then onto the other troubleshooting techniques.
 
Thank you for such a quick reply! I know only a very little about monitors. I do have a digital multi-meeter, but what is the "b+" voltage? Is that the brown line? Is it supposed to be 120AC? I'm checking the fuse right now.
 
the b+ is the DC voltage going to the monitor. you most likely have a g07 monitor in the centipede. here's a picture of the chassis, which is what the pc board and associated components are called.

go7-1.jpg


to check the b+, first set your multimeter to DC voltage. then put the red lead on the back leg of the resistor (that the wire is connected to) on the left hand side (circled as b+ measuring point in the picture) and the black to ground, which is any part of the metal monitor frame. it should read 120v, or something fairly close to that.
 
also, another way to tell if you're getting high voltage is you'll see 'neck glow' from the monitor neck. if you look at this picture, you should see the clear glass part of the tube which is called the neck, at the very back of the tube where the neck board (pcb) connects. if you look at this part with the lights turned off in the room and the game on, you should see a dim orangey-red glow from it. if you don't, there's a problem somewhere. don't touch it, though. the glass is pretty fragile there and can break easily.
4259690034_53a7280cda.jpg
 
the b+ is the DC voltage going to the monitor. you most likely have a g07 monitor in the centipede. here's a picture of the chassis, which is what the pc board and associated components are called.

go7-1.jpg


to check the b+, first set your multimeter to DC voltage. then put the red lead on the back leg of the resistor (that the wire is connected to) on the left hand side (circled as b+ measuring point in the picture) and the black to ground, which is any part of the metal monitor frame. it should read 120v, or something fairly close to that.

Ok, the fuse is too far under the tube to reach without removing the monitor's PCB, the same goes for the +B point. I measured the voltage going to the monitor from the brown/white wires and got 128vAC, isn't that too high?

I really want to measure the points your referring to, but I know I need to discharge the monitor first, and I have always been deathly afraid of trying that because I do not have a tool for measuring the anode for voltage. How would I know I discharged it with just a lamp cord?
 
AH HA! No "neck glow". I disconnected the game board connectors to protect the game during testing. So, Voltage going to the monitor is 128vAC, but the monitor won;t glow. I can't see the fuse without removing the PCB though. Would it be worth it to try? I mean could it still be a fuse?
 
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