Tube Swapping Questions

[SirPeale]

I just found an older TV by the curb.  It's got an A51ACG26X tube in it.

The yoke meters like this: H 4.2    V 14.2

According to the tube swap list in the FAQ there's nothing really close to those yoke values.

Could I add in a resistor to get the resistance higher?  I have an unknown monitor that I broke the neck on, but the values are much different.  Like H 2.1   V 44.3 or something (those I didn't write down, it's in the shed out back and I just wanted to check it real quick).

Or could I just swap the tube and yoke altogether?

[grantspain]

do you have access to an inductance meter as it will give a more appropriate reading of the yoke
you could try swapping the yoke over but my guess is you will get some real purity issues

[SirPeale]

Nope, that's one thing I don't have. Heck, there's a lot of things I don't have, but this isn't anything I'd have at home.

[qrz]

here's a "trick" to try. with a fine tip marker, place a ref line around the "donor" crt's convergence ring.
then do the same for the yoke . carefully remove both . install the original monitor yoke as close to the mark as possible.  reinstall the "donor" conv rings in the orig position. with any luck, there won't be any purity issues .

qrz

[SirPeale]

here's a "trick" to try. with a fine tip marker, place a ref line around the "donor" crt's convergence ring.
then do the same for the yoke . carefully remove both . install the original monitor yoke as close to the mark as possible.  reinstall the "donor" conv rings in the orig position. with any luck, there won't be any purity issues .

IIRC I tried this the last time I found a tube.  Tried doing this with an old K4600.  It didn't work so well. 

[qrz]

here's a "trick" to try. with a fine tip marker, place a ref line around the "donor" crt's convergence ring.
then do the same for the yoke . carefully remove both . install the original monitor yoke as close to the mark as possible.  reinstall the "donor" conv rings in the orig position. with any luck, there won't be any purity issues .

IIRC I tried this the last time I found a tube.  Tried doing this with an old K4600.  It didn't work so well. 

yes, there are variables that can jump up and bite ya in the rump.  but, using the original monitor yoke ensures compatability that the tv yoke may not provide.  same goes for the tv's convergence ring  ( already set for the tube )
as with most skills, it will become easier with practice ........

qrz

[qrz]

if anyone cares.......
on humpday, found a 19" sanyo tv face down in someone's trash.
salvaged the unit and then swaped crt's in a game that came in monday....kept the tv conv ring so no fuss on convergence . though wrong impeadance on the yoke (so, copper recycling there ). installed orig monitor yoke and a few adjustments later... , looking like new . 
my cost on the crt -  $0 

qrz

[SirPeale]

Nice!

I still have to do it on this one.  I've been going to bed early these days, and the only time to do things like this is after the kids are asleep.

[qrz]

funny how it is . when they are too young to be of any actual assistance , they are eager to help .
when they ARE old enough .......forget it   

qrz   

[SirPeale]

I have a tube compatibility chart.  It was made by VDC corp.  Very handy.  I'd post it here, but it's 3.5M.

I used to have another chart that detailed the pinout of tubes, but I can't seem to find it.  Any ideas?

edit: answering my own question:

http://bkprecision.com/download/documentation/100-CRT.pdf

[Arm123]

funny how it is . when they are too young to be of any actual assistance , they are eager to help .
when they ARE old enough .......forget it   

qrz   

lol...  your so right !  That applies to many other things as well.

[SirPeale]

I marked the purity rings on my donor tube, and that's when I made my discovery: the rings and yoke are one piece.  Crap.

I'll have to see if I can cut them apart.

[SirPeale]

Worse problem...the tube won't fit into the frame.  The mounting tabs are *just* too big.

Well...crap!

[Lutus]

Got what you paid for!  HAHA

[SirPeale]

I'm going to do some minor surgery on my frame with my Dremel and a cutting disk.  I think that'll work.  If not, no hard done, just time lost.

[SirPeale]

Cutting the frame didn't help.     The band around the face of the tube is mounted the reverse way from the other tube.  I could bolt the tube to the frame, but I'd never be able to get the chassis back on to the frame. 

So...if anyone needs an A51ACG26X with no burn...I've got one.

[qrz]

 and for those that don't know , thats a 20" crt   

a48 = 19 "
a51 = 20"
a63 = 25"
a68 = 27"

etc........

beware of bonded yokes !


qrz

[SirPeale]

Bah, you're right!  I should have picked up on that as soon as I cracked the case on that TV.  I wasn't paying attention, I was just so happy that the tube socket was compatible. 

At least the chassis will yield a ton of parts.

As for bonded yokes, I haven't had a problem with them yet, you just have to be careful when removing the bonding agent.