Donor Tubes from Goodwill

Vongoosewink

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Anybody ever check Goodwill for useful donor TV's?

The first Saturday of each month, everything in the store is 50% off. My wife and I went last month looking for bargains, and I noticed that each store had about a dozen 19" TVs, lots of different models. Yesterday we went again, and I came prepared, I printed and brought along the list from Junknet:

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

We looked at the 3 Goodwill stores on our side of town, and I found 2 TV's that I think will have useful tubes in them, each for $10. They did not have any of the exact models on the list, but I had brought a little flashlight and looked in the back, to find the tube number inside. I few I couldn't see at all, but I managed to find 2 that have the same tube numbers as the list.

The one on the right is a Zenith Z19A11S, and the tube inside is number A48ACB32X, same as the Zenith Z19A02G from the list. The list doesn't specify what monitor this can be used for though.

The one on the right is a Daewoo DTQ-2023FC, the tube inside is number A48JLL40X, same as the Daewoo DTQ-20J4FC from the list. The list says this is a drop-in replacement for a K7000.

I don't know a lot about this, but hopefully the tubes inside are correct, and I'll be able to use them!

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I wait untill they come up on craigs for free
 
Nice catch!
I keep an eye open on craigslist as well, but it gets annoying trying to get model numbers from an owner who wants it out of their house and has no clue. Most people around here just throw them in the trash these days.
 
Nice catch!
I keep an eye open on craigslist as well, but it gets annoying trying to get model numbers from an owner who wants it out of their house and has no clue. Most people around here just throw them in the trash these days.

Exactly. I feel awkward even asking that sort of thing from somebody who is giving it away free -- they just want to be rid of it. Even at $10 each, Goodwill was worth it just to have all of them together and be able to look in the back, very convenient.

I also found some fluorescent strip lamps to replace my broken marquee lights, each for $2!
 
Hey can you get ohm readings off the yokes for horiz and vert? If so PM me and I'll add these to the list.

FYI - The list will be updated soon, hopefully before the end of the week. I have a handful to add that have piled up, both donors and duds.
 
Hey can you get ohm readings off the yokes for horiz and vert? If so PM me and I'll add these to the list.

FYI - The list will be updated soon, hopefully before the end of the week. I have a handful to add that have piled up, both donors and duds.

OK, I've never done this before, so here's what I did. Somebody please tell me if I did anything wrong!

I opened the Daewoo and discharged it, tested with the multimeter set to 200. I made contact on the exposed part of each wire where it connected to the yoke.

Horizontal (Red/blue) tested: 3.5
Vertical (Yellow/green) tested: 14.2

According to the Junknet list, the Daewoo tube is a drop-in for a K-7000. Are these readings compatible? They look about twice what the K7000 is supposed to be.

Let me know if it sounds like I did that right, and I'll test the other one.

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13 and 19" K7xxx series are going to be typical low impedence (Resistance values of around 13-15 ohms on the vertical).

25" and 27" K7xxx series will be very low impedence (Resistance values of around 7-9 ohms on the vertical).


Typical 13/19" Summary:
WG:
K4600/K4700: Very low (8 ohm)
K4800/K4900: High (48 ohm)
K7xxx: Low (14 ohm)

Electrohome:
G07-CBO/FBO: Very high (55 ohm)

Sanyo (Nintendo)
20EZ: High (48 ohm)

Hantarex:
MTC900e: Low (14 ohm)


Any set made from around 1998 onward that looks even close to the Daewoo here, of any 'brand name', will be 8 pin neck, 14 ohm vertical and direct drop-in replacement on the K7xxx without yoke swap. These all are from the same Daewoo factory and simply have random mfg names on them like Westinghouse, Sylvania, Orion, etc... All should have Orion tubes IIRC.

Note: You may not be able to use the attached TV degaussing coil -- the can cause the fuse to blow on the K7xxx chassis. Make sure you use the original coil from the arcade tube or find a coil from an older mid-80's TV set and use that. The newer coils aren't the correct ratings to work from my experience (noticeably thinner)


Likewise, MOST mid to late 1980's Emerson made sets (woodgrain cab, controls+spearker on right) will be drop-in replacements for a Hantarex MTC-900e. Unfortunately you will need to do some creative connecting for the yoke wires since Hanatrex used a completely different connector than any other supplier.
 
OK, so moving on to the Zenith.

Here's my next question... the Junknet list says that the Zenith Z19A02G has a CR-23 socket, with readings of Horiz-3.4ohm and Vert- 8.4ohm. The Zenith I picked up has the same tube, so I expect it to have the same socket and readings (but don't worry, I'm going to check.)

But here's what I don't understand about tube swaps -- there are several monitors that have the same CR-23 socket, but all have different yoke readings. How do I use this tube with a CR-23 monitor with different readings? I'd like to use it with a G07, but it has readings of 54.5 and 2.6 -- I understand that these can't work together, so I'd need to swap the original tube's yoke over to the new tube. The Junknet page just has a 'coming soon' under the "Yoke Swap" topic, which is what I need to do, right? How difficult can I expect a yoke swap to be?

Thanks for any help, I'm just trying to get my head around this whole thing!
 
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Yoke swaps aren't that bad. You won't know what you're dealing with until you try it. I have been lucky with every tube swap I have done, I have also swapped the yoke and they turned out ok. The main problem I face in a tube swap is convergence. Sometimes you can get it almost perfect and sometimes it's barely acceptable.
 
That one you checked the ohms on, man that DOES sound dead on what I've measured K7000's at before. It'll probably look really nice in a K7000, with that yoke.
 
That one you checked the ohms on, man that DOES sound dead on what I've measured K7000's at before. It'll probably look really nice in a K7000, with that yoke.

Yeah, the funny thing is that out of my 17 games, not a single 19" K7000 to be found. Bunches of WG4600s and G07s though.

Only hurts when I laugh!
 
I can't tell, is that the skinny neck or the thick neck? If it's skinny, you're only going to be able to use it on a K7000 anyways. If it's fat, you'll probably never find a 19" with a neckboard that will fit it! They did make some but most of the 19" neckboards are for the 8 pin tubes.
 
One thing I learned the hard way...keep the original convergence rings with the donor tube and mark their position before removing. Just swap over the yoke. It will make life easier.
 
One thing I learned the hard way...keep the original convergence rings with the donor tube and mark their position before removing. Just swap over the yoke. It will make life easier.


Exactly. Mark where they were, and put them exxxxxxxxxactly back in the same spot, on the same tube.
 
I can't tell, is that the skinny neck or the thick neck? If it's skinny, you're only going to be able to use it on a K7000 anyways. If it's fat, you'll probably never find a 19" with a neckboard that will fit it! They did make some but most of the 19" neckboards are for the 8 pin tubes.

I'm not really sure the difference in the skinny or fat neck. Are you talking about the actual neck of the tube glass? I can get more photos if that would help.
 
I've done one tube swap on a G07, swapping the yoke from the G07 to the new tube. I messed with it and messed with it...it didn't seem possible to get the convergence super close. Whatever I did, one or 2 corners was out a bit. I'll probably use it in something where it won't be too annoying. From what I read, sometimes you can get it dead on, sometimes the original yoke just will not converge perfectly with the donor tube. I wore heavy gloves and didn't get zapped, but moving that yoke while the monitor is on makes tube discharging seem tame.
 
I'm not really sure the difference in the skinny or fat neck. Are you talking about the actual neck of the tube glass? I can get more photos if that would help.

The 8 pin tube will be skinnier (the glass part) and will have places for 8 pins on the end of the tube. The 10 pin tubes are thicker, physically. The only monitor the thin ones work on is the K7000, there are also 19" K7000's that use the 10 pin tube but you don't see them very often.

Just 'eyeballing' the picture, it looks like that's the 10 pin thicker tube, so while the tube itself will work on a G07 etc. and the Yoke is perfect for a K7000, you're unlikely to have a K7000 that takes a 10 pin tube

(What I'm saying is, you're going to have to take the yoke off no matter what)
 
Thin neck...glass is approximately an inch or so diameter.

Thick neck...glass is around 1.5 inches.

I haven't written up the yoke swap yet because I figured Id do it while actually doing one to get pics, etc but Ive been so swamped I just haven't gotten around to it yet. Heh I'm even posting this at 3:15am.

One note on convergence and how some don't work...if you look at the tube itself I think there's a code like 19V90 embossed on the side (the dark portion). I think that's an angle...I think I've seen 19V100 and that prob wouldn't work with a yoke intended for 19V90.

I know a guy that used to actually build picture tubes, Ill have to ask him sometime.
 
Did my first swap today -- got 3 19 inches for $12 bucks at a fleamarket today

1 was a 20 so it was out the other 2 looked good according to the tube list both CR23's

I swapped the tube and yoke in a WG4906 that was super burned -- mostly works

I think it need degaussed on 1 side now -- or is it a york problem? The static look uniform on the TV before I tore it apart. Could it be it just needs degaused now that in has a different degaussing coil and the different ground strap

I wasn't sure whether to push the yoke down as far as it work go or try and line it up with the old marks in the tape form the original yoke?

I used the the tutorial on junknet -- but the yoke part was to be filled in so I wasn't sure being my first shot.

At least it worked for the most part

do I need to move the yoke?
 
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Did my first swap today -- got 3 19 inches for $12 bucks at a fleamarket today

1 was a 20 so it was out the other 2 looked good according to the tube list both CR23's

I swapped the tube and yoke in a WG4906 that was super burned -- mostly works

I think it need degaussed on 1 side now -- or is it a york problem? The static look uniform on the TV before I tore it apart. Could it be it just needs degaused now that in has a different degaussing coil and the different ground strap

I wasn't sure whether to push the yoke down as far as it work go or try and line it up with the old marks in the tape form the original yoke?

I used the the tutorial on junknet -- but the yoke part was to be filled in so I wasn't sure being my first shot.

At least it worked for the most part

do I need to move the yoke?


Try degaussing first. If it wont go away then you probably need to move the yoke in or out. Turning the yoke will turn the picture.
Like they said, keep the original rings with its tube. I run a bead of hot glue to lock them together before removing them. This way you only need one mark to get them back where they belong.
 
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