Rejuvenated WG K7197 looks greenish/yellowish...

[MKFan4Life]

I am just learning to use a rejuvenator I bought and made a mistake during the Clean/Balance process (didn't return to Test mode to observe emissions before using Clean/Balance on each gun).  The unit is a B&K 467 and the tube was a Zenith G-A63ADG25X with a WG-K7197 chassis.

All guns showed bad emissions (1/2 way or lower into the Red BAD area) upon starting rejuvenation.  The Green and Red guns ended up GREAT but the Blue initially got a little up in the Yellow area after rejuvenation, but then went DOWN (weird?) after the Clean/Balance selection when I was trying to get the tracking tested.  I could not get the tracking to respond (meters would not go up at all when trying to set them to the tracking mark) so I did the Clean/Balance.

I DID however, make a MISTAKE at first.  When it said to do the Clean/Balance if tracking failed, I FAILED to go from each Clean/Balance process BACK to the Test mode to observe the meters.  I ACCIDENTALLY went from one gun to the next (waited 20 seconds between guns & waited for each gun's meter to fall to 0.2) but I DID NOT go back to the Test mode after each gun.

Could this have damaged the Blue gun somehow?  After I noticed I did this (almost immediately), I went to the Test mode and the Red and Green guns were reading about 1/2 way into the Green GOOD area, but the Blue was just in the Red BAD area.  I carefully read the directions which stated to attempt the Rejuvenation again on any gun that had Bad emissions, and could get it back into the Yellow area, but after that, each attempt to check the tracking would fail, leading me to retry the Clean/Balance on the Blue gun, AGAIN leading to the Blue gun reading in the Red again.  I was afraid to keep attempting this, so I stopped.

The final readings had the other 2 guns over 1/2 way up into the Green but the Blue was dead on the mark between the Red and the Yellow.  My monitor looks like it has a greenish/yellowish haze over it to me, and it only looks good (as far as color goes) when I crank up either the Blue Drive or Blue Cut-Off, but then anything white gets a smear of purplish color going to the right.  If I adjust these back down to correct this, the screen looks greenish/yellowish again.

The one good thing is the clarity and the focus seems FANTASTIC now.  It was a little blurry before (at best focus adjustment).  Would there be anything I could do to remedy this situation save getting another tube?  Thanks for any help.

[lilshawn]

some tube don't do the color tracking test very well.

ideally you want to test all three colors emission and observe which one(s) are going to need the most attention.

by all means, if your blue still reads low, try another clean cycle. who knows it may take 3 or 4... Ideally you want all the colors to emit the same amount, but that is not always possible, which is what your gain and cutoff controls on the neckboard are for...to tweak the output of each color so it's the same across the colors. at least try to get the blue back into the low green if it's that low.

that said....standard disclaimer also applies....

you rejuvenate at your own risk, rejuvenating a tube can make it last considerably shorter than normally expected. you ALWAYS chance burning out the gun or the heater and then you have no choice but to toss it. I take no responsibility....your mileage may vary... objects in mirror are larger than they appear... exact change only.

[MonMotha]

Instead of turning up blue (which is going to make it bloom and do all sorts of nasty things), turn DOWN the other colors to compensate.  The screen will be dim, but whites should be white.

Remember, gain adjusts the maximum intensity while cut-off adjusts the black level.  You should set cut-off so that black is just barely black, and gain should be set to equalize all the color intensities.  Contrast can then be used to effectively vary all three color gains at the same time for a more or less "intense" picture.

[lilshawn]

Instead of turning up blue (which is going to make it bloom and do all sorts of nasty things), turn DOWN the other colors to compensate.  The screen will be dim, but whites should be white.

Remember, gain adjusts the maximum intensity while cut-off adjusts the black level.  You should set cut-off so that black is just barely black, and gain should be set to equalize all the color intensities.  Contrast can then be used to effectively vary all three color gains at the same time for a more or less "intense" picture.

though i agree with you 100%, we still have an issue with a very nearly unacceptable output from the blue gun compared to the others.

I went to the Test mode and the Red and Green guns were reading about 1/2 way into the Green GOOD area, but the Blue was just in the Red BAD area.

[MKFan4Life]

Instead of turning up blue (which is going to make it bloom and do all sorts of nasty things), turn DOWN the other colors to compensate.  The screen will be dim, but whites should be white.

Remember, gain adjusts the maximum intensity while cut-off adjusts the black level.  You should set cut-off so that black is just barely black, and gain should be set to equalize all the color intensities.  Contrast can then be used to effectively vary all three color gains at the same time for a more or less "intense" picture.

Exactly what I tried (and logically thought might work), but although you would think it might do the trick, the results aren't much different.  Screen remains greenish/yellowish overall.  Only way I have still been able to get whites white is to ad a ton of blue and then it bleeds or BLOOMS as you have stated.  I think I might try one more Clean/Balance with the rejuvenator, but I think this poor blue gun is ready to give up the ghost.

Oh yeah, I keep saying GAIN but the neckboard says DRIVE, but I guess the terms are basically interchangeable aren't they?  I thought one of my arcade monitors had them labeled GAIN and CUT-OFF.

Thanks for all the suggestions!

[MonMotha]

Yeah, if the tube's outputs are really that mismatched, you may not be able to get things satisfactorily adjusted.  At that point, the tube is otherwise trash, so might as well hit it with anything you think might help.

As for your terms, yes, gain and drive are interchangeable.

Gain = Drive
Bias = Cut-off

[MKFan4Life]

Yeah, if the tube's outputs are really that mismatched, you may not be able to get things satisfactorily adjusted.  At that point, the tube is otherwise trash, so might as well hit it with anything you think might help.

As for your terms, yes, gain and drive are interchangeable.

Gain = Drive
Bias = Cut-off

Ah, ok.  Gotcha.  I am preparing the tube as I type this for another attempt with the B&K 467.  Just discharged it about 3 times (15 minutes between attempts).  Geeze.  I NEVER get any POPS, lol!  I think all 3 of my games have self-discharging monitors.  Will let you guys know if the attempt helps!  THANKS!

UPDATE:
Tried Clean/Balance... worsened the emissions...  Did rejuvenate to the blue gun again and it went to highest mark in BAD section, but that's all I could get.  Other 2 guns still holding past 1/2 way up in the Green, so they are excellent.  Here's some pics:







Fantastic focus... too bad the blue is so weak...

[lilshawn]

Just discharged it about 3 times (15 minutes between attempts).

actually, i never remove the anode from the tube while rejuvenating. I pull the neck board, pop on the adapter, and let 'er rip.

how many times now have you done a rejuve on this gun now??? i wouldn't reccomend more than once, but ive had to cook a tube nearly 10 times before the output was acceptable again. of course it was a tube that we would have tossed anyways, so if we killed it, no big deal.


but, give this a try

sometimes if a tube gun is especially bad, i switch the tester to the emission test and turn up the grid voltage until the "good" guns JUST reach the max end of the good scale. and then check the bad gun emsission. if it's better, i turn up the heater a bit and then do a clean/restore on the BAD GUN ONLY. make sure you release the button when the meter shows into the red area.....

let it rest for a minute then RE-SETUP from zero back to the beginning and check the emissions again and see where your at.

again, standard disclaimers apply.... I take no responsiblablabla....may cause diarrhea... contact your doctor immediately if you get an erection lasting longer than four hours... machine takes tokens only.

[MonMotha]

actually, i never remove the anode from the tube while rejuvenating. I pull the neck board, pop on the adapter, and let 'er rip.

I have been told that if you don't discharge the anode that "crud" from the rejuvenation process can be attracted towards the front of the screen and become lodged there creating a spot.  That wouldn't be good.  Also why you should have the tube in an orientation other than "face down" for said process.

[lilshawn]

crud will land where it lands. i wouldn't do it face down of course, that would guarantee clogged shadowmask/ap. grill but due to the nature of the rejuve process, there isn't allot you can control.

i guess if it make people more comfortable to discharge before a rejuve, then go for it, i'm just saying that i don't bother.

If a tube is getting a rejuve, it would be a tube that otherwise would be tossed, so if it works, it works, if not, oh well is the way i see it. I don't usually rejuve tubes unless it needs it, and badly, and there isn't another tube in the shop to replace it, or a new one to put in there.

gennerally the rejuve works and the tube gets another year or so, if the emmissions are still in the toilet after a few burns, *TOSS*.

[MKFan4Life]

Well, I didn't remove the anode, I just used the home-made discharging tool (screwdriver with heavy gauge wire clamped to it and other end soldered to an alligator clip) to slip under the cap and discharge the tube into the monitor frame.  I heard you could DESTROY the rejuvenator if you didn't do this, and even the PDF file I used to go step-by-step for the process (straight from the B&K website) says to completely discharge it before connecting it to the tester.  Maybe not doing the discharge will give me some extra UMPH to blast the blue gun clean?  Lol!  Just kidding.  Sounds "VERY SCARY" to me (in Sol Rosenberg's voice from the Jerky Boys CD's)...lol!

Anyone else recommend what lilshawn said might bring the blue gun back into the green (turning up the voltages)?

[lilshawn]

my guess is nobody would.  since it's not something your really supposed to do.

like i mentioned, i'm rough as hell on tubes with the rejuve since they would be tossed regardless. I could care less if it blew out the guns.

you on the other hand, are trying this on your (quite possibly) one and only tube.

you may want to err on the side of caution with regards to operating outside the factory recommended guidelines.

but you could be open to experimentation, who knows but you, i just wouldn't do it with my one and only tube.

[MKFan4Life]

you could be open to experimentation, who knows but you, i just wouldn't do it with my one and only tube.

I generally would be open to experimentation since the blue gun is so bad.  But on the other hand, yes, it's the only tube I have for this machine unless I rip the one from my MK2 which would leave it sitting until I found another one, so I guess I'll play it safe until I have a likely replacement option readily available.  Thanks for the info though.

I was thinking of looking into swapping in a TV tube if I could find a likely replacement that would work, but that is new ground for me, but I LOVE new ground, lol.

[lilshawn]

have a look here.... http://forum.arcadecontrols.com/index.php?topic=101394.0

we just went through a tube swap... it's got some pointers

[MKFan4Life]

Thanks... I'll read through it.