Chassis Identification and troubleshooting

[skforty]

Hello,

I just picked up a 27'' 31 khz VGA monitor.  I believe the monitor is EYGO due to a sticker on the tube, my google-fu didnt return anything useful.  I heard eygo's are just wei-ya?  The problem i am having is the screen flickers really bad, like its blanking...i can get a video in a little bit, once i put the chassis back on, but when i looked at the chassis, on the neckboard, there is a spark, that is flashing at the same rhythm as the flashing on the screen.  The component is at SG701...the third pic.  Im showing my nooby-ness, because ive never seen something like that spark on the neckboard, it looks like an voltage arc, is this supposed to happen?  What component is that, it looks like a resistor, but ive never seen one thats see thru like that, and usually resistors are marked as R on the PCB, like the rest of the resistors...

Any help would be greatly appreciated, thanks!


Anyway, here are some pics.

[lilshawn]

it's called a "Spark Gap"

basically if the high voltage gets shorted  inside the tube or inside the flyback transformer, the spark gap provides a path to ground that the high voltage can go, but otherwise remains open. it's so the high voltage doesn't end up someplace else during self destruction... like your joystick. since your neck card and jamma harness are linked together....

[skforty]

thank you! I see, So similiar to the suggestion on another forum was to test the tube...I will look into doing that.  Suppose the tube is okay, how would i test the flyback?  Would that be the next step? Or would i just replace the flyback...ive replaced them before, but never tested them.

Thanks!

[lilshawn]

you need a special tool to test a flyback. the tube is probably still good, the spark gaps are doing their job.

flybacks often fail, but they do so very spectacularly, which is the reason for the "spark gaps"

if while it's operating you have an arc in one of the spark gaps, you have a probable issue with the flyback. i would look at the b+ and be sure it isn't too high. if it's good then you likely have a flyback issue that will need replacing.