Tube Swap Info

[Phetishboy]

Where can it be found again? Is it orion who was compiling it? I have 2 19 TV's to crosscheck. A Daewoo and a Mitsubuishi, both look early 90's, just pulled them from the dumpster. I will check them over later, but I will need the reference guide.

 

[RetroHacker]

There are so many hundreds of different TV's out there, that any attempt to catalog them is going to leave most of them out. I saw one page somewhere that had like a dozen sets listed.

Most sets I have run across have usable tubes. When in doubt, if it's free, take it, and check it out when you get home.

First off, make sure the tube is the right size. 20" TV's look very similar to 19" ones, but the tubes won't fit in an arcade monitor frame.

Open the set and check the neck connector. If it's the same as the arcade monitor's, then there's a very good chance it'll work. You can also look up the tube number in the B&K tube tester manual, and make sure it uses CR-23.

Optionally, you can ohm out the yoke and compare it to the arcade monitor. I've had good luck matching tubes to K7000's like this, but little else. Usually, you keep the yoke with the arcade chassis, and move it onto the donor tube. Just mark the convergence rings before you pull them off, and put them back in the same place. Yoke stays with the chassis, convergence rings with the tube. Likewise, try to keep the degaussing coil with the chassis.

-Ian

 

[tta583]

This from Orion3311?
http://www.junknet.net/index.php?option=com_content&view=article&id=121&Itemid=121

If you are shopping for TV's try and get a setup guide for a B&K or a Sencore CR-70 Beam Builder. I think the B&K is on line. Not sure the format..may be able to print it. Anyway, I have been known to take a little LED flashlight and one of my Sencore setup manuals to a thrift store. I have yet to find a TV of the 80's vintage where I could not see the tube number through the vents with a decent LED flash light. Look it up and see what socket it takes. On the Sencore its a socket 3 to fit your "standard" monitors. You, however, have to recognize actual settings to know you have a match. On the B&K you just see Socket 23. The B&Ks are hard wired in the sockets vs a more generic socket with the Sencore and the a need to "set up" the unit for the specific tube.

 

[Phetishboy]

This from Orion3311?
http://www.junknet.net/index.php?option=com_content&view=article&id=121&Itemid=121

If you are shopping for TV's try and get a setup guide for a B&K or a Sencore CR-70 Beam Builder. I think the B&K is on line. Not sure the format..may be able to print it. Anyway, I have been known to take a little LED flashlight and one of my Sencore setup manuals to a thrift store. I have yet to find a TV of the 80's vintage where I could not see the tube number through the vents with a decent LED flash light. Look it up and see what socket it takes. On the Sencore its a socket 3 to fit your "standard" monitors. You, however, have to recognize actual settings to know you have a match. On the B&K you just see Socket 23. The B&Ks are hard wired in the sockets vs a more generic socket with the Sencore and the a need to "set up" the unit for the specific tube.

No, I have 2 working 4900's with horrible Burger Time burn in both tubes. I would be trying to get 2 tubes to replace those in my 4900's.

 

[tta583]

Post the Tube numbers. I, or someone with a rejuv, will look up the numbers for you if need be.

 

[Phetishboy]

Post the Tube numbers. I, or someone with a rejuv, will look up the numbers for you if need be.

Yep, will do when I get home. I hope these work.

 

[RetroHacker]

Here's the manual for the B&K rejuvinator:
http://www.bkprecision.com/download/...on/100-CRT.pdf

If the tube is listed as a CR-23, then you're good.

Honestly though, not every tube is listed, and I've had tubes that weren't on the chart that worked just fine. As long as the neck connector is right, it usually works just fine.

-Ian

 

[Phetishboy]

Here's the manual for the B&K rejuvinator:
http://www.bkprecision.com/download/...on/100-CRT.pdf

If the tube is listed as a CR-23, then you're good.

Honestly though, not every tube is listed, and I've had tubes that weren't on the chart that worked just fine. As long as the neck connector is right, it usually works just fine.

-Ian

Ian, your link doesn't work.

Here are the tube specs:

Monitor (WG-7200) Date: 2001
A48JLL40X46 (Q)
71251356
8 pin neck

Donor Tube (Daewoo 19 in TV) Date: 1995
A48JLL40X (w)
35116543
8 pin neck

Can someone give me an idea if that will work? My 4900's both have 10 pin necks so they won't work. Luckily I had this newer 7201 sitting here with a broken tube, I think it's time to fix her up.

 

[RetroHacker]

Those tubes are perfectly usable as arcade tubes, but only for 8-pin chassis. You can't use an 8 pin tube on a 10 pin chassis. You need to find older TV's I've swapped 8-pin tubes into 19" K7000's and they worked great.

-Ian

 

[Phetishboy]

Those tubes are perfectly usable as arcade tubes, but only for 8-pin chassis. You can't use an 8 pin tube on a 10 pin chassis. You need to find older TV's I've swapped 8-pin tubes into 19" K7000's and they worked great.

-Ian

Yep, I edited my post so it would make more sense. I still have an older TV for my 4900 swap, just got break into it. I have a 7201 here in need of a new tube, this tube should work then. Swap yokes? Or keep the TV yoke?

 

[RetroHacker]

Yep, I edited my post so it would make more sense. I still have an older TV for my 4900 swap, just got break into it. I have a 7201 here in need of a new tube, this tube should work then. Swap yokes? Or keep the TV yolk?

Check the yokes with the meter. I've had real good luck with TV yokes being compatible with the K7000. Check the horizontal and vertical windings for resistance, and compare them to the arcade yoke. Last one I did was almost spot on, and it worked perfectly. With the 4900, however, you're probably going to have to swap the yoke.

If you have to swap a yoke, mark the convergence rings with a Sharpie, and the place on the tube. Slide the convergence rings off carefully, swap the yoke, and put the convergence rings right back where they came from. So, the rings stay with the tube, and the yoke goes with the chassis. Leave the yoke loose, fire up the monitor and display a solid green screen. Adjust the yoke so that the purity is correct (i.e. the screen is solid green, no blotches of color) and the picture is straight. Check red and blue screens for color purity issues too. Fine tune the convergence by using a crosshatch pattern. Make sure the center convergence is good, edge convergence is done by flexing/moving the yoke, or using those little convergence strips (tiny squares of metal, insulated with plastic, at the end of plastic strips). The first time you do it, expect to fiddle with it a lot. After you get good at it, it'll be easier.

-Ian

 

[Phetishboy]

I just swapped yokes. I have everything hooked up, plugged in the monitor and I have neck glow, no picture. Just black, nothing, no color, no light, no movement. Nothing. I have turned the black and contrast pots on the remote board and the flyback screen knob, but nothing I do makes any difference. What now? I have power, video hooked up, focus and ground wire on, degaussing wires plugged in.

 

[LyonsArcade]

Check the pins to make sure you didn't bend one of the heater pins.

 

[LyonsArcade]

WAit, you have neck glow, so your problem might be the screen voltage.

 

[Phetishboy]

WAit, you have neck glow, so your problem might be the screen voltage.

No bent pins. Please advise. Screen voltage?

 

[LyonsArcade]

K7000, right? Use your meter and check first to make sure you have B+ voltage at that big white resistor on the side. It should be 123 or something close. Use the DC, put the ground lead on the frame, the other on the post on the resistor. If that's cool (it should be, you have neck glow), then check the voltage where it comes in on the red line into the neckboard. See what it measures out at.

The way I understand it, the image is created by the difference between the screen voltage (grid) and the heater voltage, and adjusted by the 'screen' control on the flyback.

 

[LyonsArcade]

Oh, also while you're at it, there's a resistor on the side of the neckboard, it'll be all by itself and sticks up about half an inch off the board. Check the voltage at one side of that, then again at the other... DC voltage. It should be between 4 and 5 volts or so, that's your heater voltage. If you have like 2 volts it could be that the heaters are working (and making the neck glow) but not strong enough to make an image.

 

[Phetishboy]

This is a K 7201. I can feel static at the front of the tube, have neck glow and can hear the flyback charge up. This is baffling to me. Everyone makes tube swaps sound sooo easy. The only thing that I am not certain on is the placement of the convergence rings on the tube. Where are they supposed to sit? Close to the yoke or close to the neck board? All my older monitors have the rings up next to the yoke, but on this one, the rings were closer to the neck board. Would having them in the wrong place cause there to be no picture? BTB, I also have a toggle switch to change from 15 - 17.7 Mhz whatever that means.

 

[Fudd]

You can move the yoke while it's powered up, move it in/out to see if you get a picture. i usually put my wifes stand up mirror on the other side and move the yoke while looking at the mirror to adjust the image. you should see a whole swirl of crazy colors except for when the yoke is positioned at the exact correct spot. if you dont see any colors at all you might not be getting a video feed maybe?

 

[Phetishboy]

You can move the yoke while it's powered up, move it in/out to see if you get a picture. i usually put my wifes stand up mirror on the other side and move the yoke while looking at the mirror to adjust the image. you should see a whole swirl of crazy colors except for when the yoke is positioned at the exact correct spot. if you dont see any colors at all you might not be getting a video feed maybe?

I'll try moving the yoke.