19K7191 Dead Tube?

kschafer2598

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Hi all,

I recently picked up an old converted Galaga cab that I plan on restoring, trying to get the electronics going first. It has a 19K7191 monitor with a K7000A chassis in it.

The tube is completely black, with no neck glow. The neck glows at first power up for a moment, and goes dark.

When I tried another K7000 chassis on the same tube, I got some blue arcing in the neck but nothing on the screen.

My assumption here is that the tube is indeed dead based on another thread I saw, where blue arcing and no other glow indicates a loss of vacuum.

Is there anything else worth checking?

Thanks,

Karl
 
Blue arcing means it's been cracked somewhere and the vacuum is gone. Rip tube, luckily k7000 tubes are easy to find.
 
Thanks man, I'll start searching. If there's anyone on the east coast with a 19" vertical monitor I'm interested!

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Thanks man, I'll start searching. If there's anyone on the east coast with a 19" vertical monitor I'm interested!

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no go to goodwill grab a few 19" tubes I guarantee you if you look for tv's from 1988-2000 one will have the correct tube
 
Thanks, never thought of that. I found this guide showing some drop in k7000 replacements. I'll see if I can locate one!

http://www.junknet.net/donor-tvs

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I found one at the first Salvation Army thrift shop I went to when I had to replace one. They had a ton of extra CRTs in the back but too but only had some of the newer ones on the floor. Also you can get lucky typing in "Free tv" on Craigslist if you have some specific models you're looking for.
 
Is there a list floating around of TV tubes that are drop ins for K7000s? The junknet guide helps but there are only a few listed for K7000s.

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Go to Goodwill. Buy 10 TV's at $5.00 each. At least 5 will be drop in replacements for a K7000. At most you might have to Swap out the yoke plug.
 
Kinda taking this thread on a down a side trail, but would this also be true for replacing Sanyo 20 EZ tubes? Is the potential success rate about the same, or are Sanyo tube swaps significantly harder to match up out of the "donated/free pool"?
 
Kinda taking this thread on a down a side trail, but would this also be true for replacing Sanyo 20 EZ tubes? Is the potential success rate about the same, or are Sanyo tube swaps significantly harder to match up out of the "donated/free pool"?

Sanyo 20EZ , G07'S, 4900's are very rare. 1in30 from my experience. You have to yoke swap those and even That can be quite difficult.
 
Sanyo 20EZ , G07'S, 4900's are very rare. 1in30 from my experience. You have to yoke swap those and even That can be quite difficult.

I've heard the sanyo tubes would be easier to find if you lived in japan. K7000's are so easy to find.
 
I found a 19A20 Toshiba TV for sale... wondering if anyone knows what tubes they have. I don't have access to it physically.

If I don't hear anything I'll probably just go for it and see if it works.
 
Picked up a TV from goodwill, swapped the tubes and it looks great!

The chassis has some issue s I think, doing a capkit now.

The TV was a Super scan 19TVD3S.

Tube was A48LRH93X.

Direct replacement, swapped the DAG, degauss and yoke wires.

Here's what it looks like:

f42674a0da3be41c2f5ef81dc2e0330b.jpg


Update: found an unlabeled pot that took care of the lines, looks great now.

Thanks everyone for the tips on using TV CRTs.
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Picked up a TV from goodwill, swapped the tubes and it looks great!

The chassis has some issue s I think, doing a capkit now.

The TV was a Super scan 19TVD3S.

Tube was A48LRH93X.

Direct replacement, swapped the DAG, degauss and yoke wires.

Here's what it looks like:

f42674a0da3be41c2f5ef81dc2e0330b.jpg


Update: found an unlabeled pot that took care of the lines, looks great now.

Thanks everyone for the tips on using TV CRTs.
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Great news :) Glad it was easy
 
One more question... There's a large resistor on the side of the chassis that's getting very hot. Is this normal?

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that high wattage resistor will get quite hot which is normal, but with anything there is always a too hot condition but normal will be too hot to keep you finger on it for than 1-3 seconds.;)
 
One more question... There's a large resistor on the side of the chassis that's getting very hot. Is this normal?

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that's your B+ resistor. the whole of the monitor's power supply pretty much passes through it. this is also where you get your B+ voltage readings for diagnosing a voltage regulator (or other) failure.

as far as Sanyos go, I tried subbing a Sanyo 25" tube for a K7000 and it didn't work. so I'm guessing Sanyos must have something unique about them.

Zeniths are a great sub, but stick to the older models from either the 80s or early-mid 90s. from about 1995 onward they weren't of very good quality and that's why you see a lot of Wells-Gardner U5000 or K7x00 and Neotec tubes fail cause that's what they used. Zenith used a pretty uniform design across all their TVs spanning that era, so they're almost always the best sub you can get. and I would imagine the yokes are probably fairly spot on for a K7000.

from your Capcom Bowling picture it looks like the 50/60 pot is out of adjustment, which is for vertical linearity. that's why you have that overlapping effect in the upper 1/3 of the picture. definitely re-cap the chassis first, and make sure you reflow all the resistors for the power section while you have it out, cause new caps can "kill" your chassis if the solder joints aren't reflowed properly.
 
The info on the hot resistor helps, that makes sense. It never got hotter than I first noticed.

I did f Ind the 50/60 pot and that cleared the image up.

I'll take it and reflow the power area.

The image is pretty good but the left side has a small dip / tear and the horizontal lines appear to be separating on the left side. I'll snap a pic soon.

Also, I noticed the color fluctuates, like theres a magnet near the time (There isn't). I has this problem with other monitors and it sorta goes away, just wondering what causes it. If I tilt the cab to one side the color goes back to normal.

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The info on the hot resistor helps, that makes sense. It never got hotter than I first noticed.

I did f Ind the 50/60 pot and that cleared the image up.

I'll take it and reflow the power area.

The image is pretty good but the left side has a small dip / tear and the horizontal lines appear to be separating on the left side. I'll snap a pic soon.

Also, I noticed the color fluctuates, like theres a magnet near the time (There isn't). I has this problem with other monitors and it sorta goes away, just wondering what causes it. If I tilt the cab to one side the color goes back to normal.

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Just degaussing get a good degaussing coil on eBay and that'll clear you right up.
 
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