FIXED: G07 HV inconsistent on and off/arc from flyback

[Tenn_pin]

Ms Pacman monitor was recapped 3 months ago and worked great for 2 months, then the HV failed.  I took it out and re-soldered all of my work and the monitor worked fine, but the colors would change (seemed to fade) during game play.  Also, there is a slight wave from right to left (primarily about 1/3 up the screen.)  Yesterday, HV failed for the second time , so I reflowed every joint on the chassis and the neck board.  Plugged it up and no HV, but there was an arc that came from the flyback to the chassis.  I shut the power off, then turned it back on and the HV came on and the colors were bright and right.  I played the machine for 30 minutes, but the colors, mainly the red, faded back.  I left the machine on for 3 hours with no change.  Turned it off and on several times and the monitor came up each time. Today, turned it on and the monitor came up, but only stayed on for 1/2 a game.  Then the HV failed again (no neck glow). Not sure which part is failing, but hope someone can point me in the right direction.

Thanks,
Randel

[Tenn_pin]

BTW, when I installed the original cap kit, F901 was blown, but F902 was good.

[qrz]

c406,412,506,511,523 and 905 should be replaced if not in "kit"
the flyback should NOT be arcing . replacement is recommended .
however, pending the area of arc , applying a liberal amount of silicone sealant may extend the life awhile....

[Ken Layton]

Sounds like the flyback is shot.

[Tenn_pin]

Thanks guys for the replies.

I replaced the FB when I did the cap kit. Where do I apply the grease to extend the life?  I don't mind ordering another one, but would prefer to know for sure that is what it is.

I will look at those caps when I get home, to see if they were in the BRoberts kit.

Randel

[qrz]

first off ..., its NOT grease . it is silicone sealant . which, is a rubbery type substance ( when dry ) that has electrically insulative properties
as well as resisting water , etc ....

if it only did it once , it may simply have been a static discharge .
 if it is persistent , there would likely be a visable mark ( carbon track)
from  a point  indicating a weakness in the insulation. this would be the spot to apply .



>>>>>>>>>>>>THIS IS ONLY A "BAND AID" AND NOT A PROPER REPAIR PROCEDURE FOR AN ARCING FLYBACK<<<<<<<<<<<<<<<<<

sorry, there is no grease to extend flyback life . 
electronics isn't mystical magical stuff . it is simply manipulating the motion of electrons between atoms

[Tenn_pin]

More info.  I have not had a chance to get the insulator material yet, but did turn on the machine with the back off again.  The HV started up and there was a small arc again, but there was also a lot of sparkles on the back of the CRT.  The HV charge went into the CRT, but the heater did not start, so no glow on the CRT.  I believe I had this problem with another G07 and it turned out to be a part that limited the CRT from emmiting X-rays.  My next search will be for HV limit system.

Thanks,
Randel

[MonMotha]

Is the ground strap running from the dag (metallic coating) on the back of the CRT to the neck board in place?

[qrz]

MON , u posted just as i composed this   

for kicks, double check the crt ground .
there should be a clip/ground wire from crt to the crt skt ground .

had a boss that ONCE tried to "help" on a Zenith tv repair . he neglected to reconnect this ground .
upon pwr up , BZAAAAP - he hastily retreated to his office spewing obscenities the entire way  
only way to deal with that charged gem was to yank the pwr cord and discharge the crt ground to the AC line ground .
and if i recall correctly , it threw a rather nice arc .

[Tenn_pin]

I do have the ground clip on the chassis.  Does it matter how far from the FB it should be clipped?

Thanks,
Randel

[Tenn_pin]

Sorry Mon, the dag strap is connected to the neckboard.

Thanks,
Randel

[MonMotha]

Sorry Mon, the dag strap is connected to the neckboard.

Thanks,
Randel

I'm not sorry, though you might be if it weren't   I was just making sure, since it might cause the symptoms you describe and is easy to fix (once you get it so that the thing won't zap the bejeezus out of you when you get within a foot of it).

[Tenn_pin]

Ok, I want to thank all that helped in this problem .  Turns out that it was R908 (Thanks Bob Roberts .)  This resistor was supposed to be a 47k, which it was.  But when I pulled it out and measured it, it had turned into a 60.45k.  Went to the local Radio Shack, got the new part, and now Ms Pacman is playing again!  I still have some very slight waviness from right to left, but according to my wife and Grandson, I am the only one who sees it.  BTW, I know it is there.  I will go through all of the ground connections and see if it is feedback from a bad ground.

Thanks Guys..

Randel