Re: Weird problem with WG 19K6100 monitor (LONG)

Sounds like you have a bad CRT socket on the neck board. You've already
ruled out the CRT by unplugging the neck board from the CRT, now it's
time to rule out the socket by disconnecting it from the neck board (or
at least disconnecting the focus wire since that's where your problem
likely is). I'm estimating focus voltage would be around 6,000 volts,
so it doesn't take much of a problem with the socket to cause arcing.

The arcing is probably disrupting the game board and causing continuous
resetting. At some point you're going to REALLY damage something if you
keep going like this.

Tony Jones wrote:

>I have a weird problem with a XY monitor (WK19K6100).
>
>HV P316
>Defl P314
>Neck P328 (on a little white sticker, yes I do have the purple wire to HV).
>
>I have no history with this, it was DOA when I got it and appears to have
>stumped the previous owner judging by the mess I had to clean up.
>
>I've fixed some problems on the deflection pcb and installed an LV2000.
>HV is 18.8KV, which seems pretty close.
>
>In short, I have what I think is a neck board problem but it also affects the
>operation of the game pcb which is really odd.
>
>Nearly all the time all you see on the screen is a rainbow like image
>indicating what looks like a lack of focus (unless you have focus cranked
>way down in which case the screen is blank).
>
>Additionally, upon first powering up, I hear a distinct buzzing/sparking
>noise from the neck pcb -- I think from the tube socket, but it's hard to
>tell.
>
>This lasts for about 30 seconds, regardless of the setting of the screen
>(brightness) or focus controls. Depending on the level of the brightness
>control, you may start seeing vectors at this point, if you do, it'll soon
>start sparking again.
>
>With the brightness set lower, the sparking noise always stops completely
>about 30 seconds after power-up.
>
>I have taken a short MPEG of this:
>http://www.tonyjones.com/games/tempestscreen.mpg
>
>There is a fair bit of background noise (PC fans etc) but you can hear the
>sparking, which stops for a couple of seconds towards the end, but then starts
>again (because I have the brightness cranked up too high).
>
>Interesting point is that whenever you hear the sparking noise, the spot
>killer is on and the game pcb isn't running correctly (see solid player 1/2
>LEDs in MPEG).
>
>As soon as the sparking ends, the spot killer goes off and the player 1/2 LEDs
>start flashing at the normal speed. At this point, the game plays fine blind.
>
>At this point, if you crank up the brightness, the sparking noise starts again
>(until you lower the brightness), spot killer lights and the player 1/2 LEDs
>go solid, or flash very fast. One time upping the brightness level like this,
>I blew F100 (I know a bad C503 can blow fuses).
>
>http://www.tonyjones.com/games/tempestscreen2.mpg
>
>In this one you can see vectors start to appear as the brightness is cranked
>up and then towards the end, the spark noise starts (spot killer lights, game
>board goes south -- player 1/2 LEDs will go solid if in attract, if playing a
>game, start hearing weird sounds etc). I'm guessing the reason I'm seeing
>vectors at times is because I have the brightness level high enough to
>overcome the spot killer circuitry.
>
>The pcb board is 100% rock solid (REALLY!!!), plays fine with the monitor
>installed into the cabinet, though I'm reluctant to keep on running these
>tests in case it ceases to be. I just plugged the game board back into the
>working monitor in the cabinet and it's been running fine for over an hour.
>
>I removed the back portion of the neck socket to expose the white wire.
>With the neck board unplugged, you hear the spark noise forever (spot killer
>lit, game board player 1/2 LEDs solid). I couldn't see any sparking on
>either the white wire or at any of the neck pins.
>
>Unsure how to remove the rest of the plastic casing around the neck socket
>to fully expose the underneath of the neck pins, is it possible ? Didn't want
>to break it.
>
>Anyone have any troubleshooting tips?
>
>- I was thinking of a) swapping a known good neck board into this chassis and
> b) installing this deflection board into a known working chassis, but
> havn't yet as I'd hate to damage known good equipment. How likely is this?
>
>- I havn't played with any of the potentiometers on the neck board.
>
>
>Tony
>
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Received on Sat Mar 15 13:22:57 2003