Tube Swap K4900 Question

daxwell

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I'm taking a ride over to Goodwill later to drop off some old winter coats. I'm hoping to find a suitable replacement tube for a WG K4900 chassis. I've looked at junknet but I don't see any that are direct drop in's for this chassis. Does anyone know any tube numbers that would work?
 
anything with a cr-23 adapter....direct drop in's mean the tv yoke would work with the arcade chassis.....basically you have to get lucky to get both the tv correct and the yoke...if you find a tv with a cr-23 adapter buy it and use the 4900 yoke with your new tube.
 
Well, I picked up the only 19" (I thought) TV they had. Paid $6.25. It rurns out that it is actually a 20". The model # had a 19 and a 20, so I figured it was worth a shot - RCA F20519AK. The tube, which I couldn't read says A51ACG14X. It is a CR-23, but I'm guessing that it won't fit in the WG K4900 frame so it's useless. Am I correct? In case anyone cares, the Yoke Reading were - Horiz 4.0 ohm, Vert 12.1 ohm.
 
Well, the neck socket can be used to make a BK adapter, but the tube won't fit the regular 4900 frame.

And next time you see a model number like that, the size is usually listed first...
 
Make sure it's a 10 pin tube and the first 3 digits on the tube ID is A48****.
If it's an A51**** it won't fit in a standard arcade monitor frame.
 
Just picked up another old TV. This one is a 19" Quasar. It has a tube A48AFN00X which is a CR-31 according to the bkprecision list so I didn't bother checking the ohms. I guess this one is a no go also. If we are swapping yokes, why does it matter what the CR is, does that represent the neck pins? Are there any arcade chassis that use a CR-31?
 
Yes, the CR-# indicates the neck pins/layout. CR-31 is commonly used on 19" K7000 monitors. I believe Vision Pro and some Sharp monitors also used it...
 
I don't think I have any K7000's. I have 2 k4900's, a cocktail table, and a centipede cabaret with the original monitor and an Arkanoid with a nice picture so I've never looked at the monitor. I'll have to check again what type of monitor the centipede has, maybe post a pic tomorrow. I know there seemed to be a few small boards in addition to the regular chassis.
 
I think you should get the readings off of the yoke anyway. Then, with that data, see if any local collector wants the tube. Also, if you could post all of the info here we can get it into one of the TV set databases that some of the guys are compiling.


BTW, I would like to get the neckboard with socket if you decide to junk the set. I use them to build rejuvenator adaptors.
 
Well I tested the yoke and the readings are Vert 16.1ohm - Horiz 5.1ohm. The pics from my centipede mini chassis are attached. I think it is a K4600, but I'm not sure. The flyback is not on the chassis, but located separately on the monitor frame. If this chassis is also a CR-23 then I will have no use for it and the search will go on. I will gladly offer the tube free to anyone who wants it.

Sorry for the bad pics but it's kinda tight inside the cab.

The TV is a Quasar Model #TP1921FE-3.
 

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You just randomly found a 19" TV with a CR31 neck? Man, I need your luck. Every 19" TV I've sourced off CL lately has crossed on the B&K setup chart as a CR23. I'm still looking for a CR-31 to use with a lonely 19K7000 chassis I have here. I could really use two, actually. I have a Dedicated Double Dragon cab that has a bit of burn in that could use a new tube.

As far as finding a K4900 compatible yoke in a TV, don't hold your breath. The yokes in the 4900's (there were 2 varieties) both ohmed out at about 35 on the vertical, which I've not seen on ANY TV that I've found OR read about. Every time I've read about a 19K49xx tube swap done, the yoke's been swapped too. Including mine.

See here:

http://forum.arcadecontrols.com/index.php?topic=105653.msg1129934#msg1129934
 
I would like to know whether or not I should be keeping this 19" CR-31 tube for myself. Can someone let me know what chassis is in my pics earlier in this thread. . I think its a K4600, but I'm not 100% sure. If it is a K4600, then I have no use for the tube and will offer it to any member that wants it.
 
I will offer it for free for anyone that wants to pick it up. If I don't get anyone to take it within the next two weeks, I'll pull the neckboard and socket for Oryk Zinyo. I'll list it in the for sale thread later today.
 
Technically you could pull the neckboard and socket for OZ anyway, as they won't be used by anyone needing the tube...
 
I'm relatively new to monitors, so when you say the neckboard and the socket, are you just talking about the part that accepts the pins (female side). Doesn't that just come as part of the neckboard? I thought OZ was asking for the male side that is on the neck of the tube. OZ, just let me know exactly what you need, and I'll pull it.
 
I'm relatively new to monitors, so when you say the neckboard and the socket, are you just talking about the part that accepts the pins (female side). Doesn't that just come as part of the neckboard? I thought OZ was asking for the male side that is on the neck of the tube. OZ, just let me know exactly what you need, and I'll pull it.

You can't take the pins off the tube without killing the tube. The plastic piece around the pins CAN be removed if necessary, but it isn't in this case. He just wants the female side to make an adapter from it.

You can actually pull anything you want from the TV except the tube, yoke, and centering rings, and the tube will still be good for someone to use...
 
I'm relatively new to monitors, so when you say the neckboard and the socket, are you just talking about the part that accepts the pins (female side). Doesn't that just come as part of the neckboard? I thought OZ was asking for the male side that is on the neck of the tube. OZ, just let me know exactly what you need, and I'll pull it.


Yeah, what Mod said. The only reason I specified the socket is because someone in the past desoldered the socket (and all components) and sent me just the PCB. They obviously spent quite a bit of time getting it cleaned up and threw away the other parts. I just didn't want that to happen again.

In order to remove the part(s) I want you just need to pull it off and cut any wires that are not easily removed. It should all be one piece when you ship it.
 
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