Hi All!
I'm desperately searching for a good used or replacement for a 12UP4A or 12LP4A CRT tube, I've had no luck at this point, does anyone know of anyone or have one of these tubes, or a replacement for it.
Mark

Hi Mark,

I remember this topic a while back. The 12LP4 was used pretty much used by everyone building TV's then. Dumont used a 12QP4 and I recall the 12UP4 was a Zenith type. I don't know where you are located but I have a 12LP4 still strapped to an Admiral chassis with no cabinet. You could have the tube but I would be afraid to ship it. I don't have any way to test it but it is still under vacuum. Any chance you are located near S.E. Pa? I would give it to you.

Fred
WA3KIO

:Hi All!
: I'm desperately searching for a good used or replacement for a 12UP4A or 12LP4A CRT tube, I've had no luck at this point, does anyone know of anyone or have one of these tubes, or a replacement for it.
:Mark
:

:Hi Mark,
:
:I remember this topic a while back. The 12LP4 was used pretty much used by everyone building TV's then. Dumont used a 12QP4 and I recall the 12UP4 was a Zenith type. I don't know where you are located but I have a 12LP4 still strapped to an Admiral chassis with no cabinet. You could have the tube but I would be afraid to ship it. I don't have any way to test it but it is still under vacuum. Any chance you are located near S.E. Pa? I would give it to you.
:
:Fred
:WA3KIO
:
:
::Hi All!
:: I'm desperately searching for a good used or replacement for a 12UP4A or 12LP4A CRT tube, I've had no luck at this point, does anyone know of anyone or have one of these tubes, or a replacement for it.
::Mark
::Hi Fred
Thats great! unfortunately I live in Omaha, NE so I have no idea how I would be able to get it, all I can say is if you packed it very well with alot of foam padding, and were able to find a shipper that would guarantee its safe delivery, I would gladly pay you for it, let me know.
Mark

:Hi Mark,
:
:I remember this topic a while back. The 12LP4 was used pretty much used by everyone building TV's then. Dumont used a 12QP4 and I recall the 12UP4 was a Zenith type. I don't know where you are located but I have a 12LP4 still strapped to an Admiral chassis with no cabinet. You could have the tube but I would be afraid to ship it. I don't have any way to test it but it is still under vacuum. Any chance you are located near S.E. Pa? I would give it to you.
:
:Fred
:WA3KIO
:
:
::Hi All!
:: I'm desperately searching for a good used or replacement for a 12UP4A or 12LP4A CRT tube, I've had no luck at this point, does anyone know of anyone or have one of these tubes, or a replacement for it.
::Mark
::

Hi Fred,

I too and seaching for a 12LP4 espectially one that has a focus coil and yoke attached to it...
The one you have sounds perfect, if you would be willing pack it up and send it to me out here in Billings, MT 59101 I would gladly give you $100.
Stan

Fred,

btw you can reach me directly @ everstan@bresnan.net

There's a web page on the internet that sells CRTs. I forgot the name. I'm sure if you search long enough you'll come up with something. The page had a yellow background. It had long lists of tubes and even had some projects for making things like a CRT clock. The site sold all sorts of tubes, both new and VERY old.

Thomas

Hello, I was wondering if a 12LA-546 would work? I have a 12lp4.

:Hello, I was wondering if a 12LA-546 would work? I have a 12lp4.

You know I asked my local tv repairman who is fairly knowledgeable and seem to think it was a occiliscope tube??? because of the strange numbering...he also indicated it has to end in p4 to work as a replacement.
PS...I saw that one on ebay too.

:Hello, I was wondering if a 12LA-546 would work? I have a 12lp4.

You know I asked my local tv repairman who is fairly knowledgeable and seem to think it was a occiliscope tube??? because of the strange numbering...he also indicated it has to end in p4 to work as a replacement.
PS...I saw that one on ebay too.

There were different numbers used at the end, but usually a P-something was used. With color tubes, numbering in this way is a bit more complicated due to the three phosphor colors used. For monochrome tubes, though, the number refers to the phosphor color and persistance (how long the screen stays illuminated after the beam has left position). Many colors are available (red, orange, yellow, green, blue, violet, white, etc., and any combination of colors to create another color) I have a P11 or P14 (I forgot) tube somewhere that has a really quick purple phosphor (like 3RP11 or something like that). This tube was used for photography work at the Hewlit Packard facilities (not sure what kind of facilities). A P1 phosphor is green and has a medium-slow persistance. This is usually used in oscilloscopes. P4 is white and has a medium persistance. A long persistance makes images stick and blur. A short persistance makes things flicker a lot. Short persistance is great for photography and such, when images don't need continuity. For oscillograph use, medium-long persistance is good, because it allows the rather slow moving beam (at times) to still make a line on the screen.

For instance: a 5BP1 is a very common and rather early/primative oscilloscope tube. A 5BP4 tube uses the same electron gun configuration, but uses a white television phosphor.

The first digit often refers to the screen size. Thus, if you have a 12 or a 19, this doesn't usually mean that the filament operates at 12 or 19 volts as with radio tubes. A 5 of course means that my 5BP1 has a 5 inch screen.

The second digit(s) refers to the electron gun configuration.

Thomas

Hello, I live near you and was wondering if that picture tube was still around?
Thanks
David