Rejuvenation help.

action76

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I have a K7000 with a R-A63ADG25X tube with a very weak red gun. I purchased a B&K 467 to try and fix it. The red gun was reading well into the red (bad) on the 467. The Blue and green were fine. I rejuvenated it about 3 times and got it into the yellow (barely). The last time I did it I had the G2 switch in the high position. The red is better than it was, but not good at all. Is there any tricks or tweaks you can do with the rejuvenator to get a better result of is this tube just beyond help?

Thanks,
Stephen
 
I don't know about the 467, but my 470 has both a "clean and balance" and a "rejuvinate" function. The "clean" usually clears up somewhat weak guns, but on really bad ones, you have to hit it with "rejuvinate". If you're still not getting anywhere, one thing you can do is bump up the filament voltage to like 7 or 8 volts and let it cook for a minute or two before doing the rejuvinate function. You risk burning out the filament, or stripping the cathode, but if it's already unusable, then you don't have much to lose.

Is this a Zenith brand tube? They made some really craptacular tubes that were used in K7000's, you might just have to replace it. Go hunting on garbage night for a 25" television set...

-Ian
 
Before you do that, I'd recommend just hooking it up and seeing what it looks like where it's at....if you haven't already. :p My green gun was in BAD before, and yellow after, and I had to immediately go turn the green level way down on the neckboard. Didn't mess with it further and don't intend to unless something comes back up. Looks great.

*Edit* Mine is a 467 with wonky meters/knobs, and a busted blue meter that never moves except during rejuv/restore. Still did the trick just fine.
 
Frax,

I did hook it up after the rejuv and it is better, but definitely not good. In order for the red to look "red" instead of dark brown/blackish red, I have to turn the red drive way up and then it bleeds terribly.

RetroHacker,

Yeah it is a Zenith.

I do have a A63LAV61X tube from a Sharp TV I have been debating on trying to swap out. The neck board is a CR-23 type and it has the same number of pins. Do you know if these are compatible?
 
Frax,

I did hook it up after the rejuv and it is better, but definitely not good. In order for the red to look "red" instead of dark brown/blackish red, I have to turn the red drive way up and then it bleeds terribly.

RetroHacker,

Yeah it is a Zenith.

I do have a A63LAV61X tube from a Sharp TV I have been debating on trying to swap out. The neck board is a CR-23 type and it has the same number of pins. Do you know if these are compatible?
If the tube uses a CR23 type you should be good to go with swapping, however you may have to also swap the yoke from the old tube over to the new one. The new one may have a yoke that will work fine but you need to ohm it out and compare it to the original.
 
I do have a A63LAV61X tube from a Sharp TV I have been debating on trying to swap out. The neck board is a CR-23 type and it has the same number of pins. Do you know if these are compatible?

Electrically, it will be compatible. The thing to check is the yoke. Measure the horizontal and vertical windings with a meter and compare the resistance to the windings on the yoke on the arcade tube. If they're close (like within a couple ohms), you can probably just leave the TV yoke on the tube and hook it up to the arcade chassis (might have to adapt the plug).

If the readings are too far off, or if the "close" yoke doesn't produce a good picture (pincushion problems, incomplete scan, etc), then you'll have to swap the yokes.

When swapping yokes, keep the convergence rings with the tube, and swap just the yoke over, and keep the rings lined up with each other and with the place on the tube - mark it with a Sharpie first.

-Ian
 
I checked the windings and the old tube is 10.7 and 1.7 ohms and the "new" tube is 8.4 and 1.5 ohms. Do you think this is close enough to swap without changing the yoke?

Thanks,
Stephen
 
I checked the windings and the old tube is 10.7 and 1.7 ohms and the "new" tube is 8.4 and 1.5 ohms. Do you think this is close enough to swap without changing the yoke?

It's close enough. It should work. Worst case, the picture will just have some distortion you can't adjust out.

-Ian
 
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