Hi All
I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
Mark

Hi Mark

You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.

Norm

:Hi All
: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
:Mark

:Hi Mark
:
: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
:
:Norm
:
::Hi All
:: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
::Mark
Hi Norm
The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
Mark

Hi Mark

No problem with 12UP4A (metal)(12D) and 12LP4 (12N).. Both actually have the same basing. The other side connection on 12N is just a coating on outside of the tube. This needs to be grounded and acts as a capacitor from high voltage to ground. Before this coating was used a 500 pf @ 20,000 volts was added for filtering.

To change over connect HV to anode connector on 12LP4 and ground the outside coating. 12LP4 is much safer as 12UP4A is a metal tube with high voltage on the shell.

Norm

::Hi Mark
::
:: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
::
::Norm
::
:::Hi All
::: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
:::Mark
:Hi Norm
: The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
:Mark
:

:Hi Mark
:
: No problem with 12UP4A (metal)(12D) and 12LP4 (12N).. Both actually have the same basing. The other side connection on 12N is just a coating on outside of the tube. This needs to be grounded and acts as a capacitor from high voltage to ground. Before this coating was used a 500 pf @ 20,000 volts was added for filtering.
:
: To change over connect HV to anode connector on 12LP4 and ground the outside coating. 12LP4 is much safer as 12UP4A is a metal tube with high voltage on the shell.
:
:Norm
:
:::Hi Mark
:::
::: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
:::
:::Norm
:::
::::Hi All
:::: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
::::Mark
::Hi Norm
:: The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
::Mark
::Hi Norm
Thanks so much for checking into this for me, I've found a replacement then:) this is absolutly wonderful! I thought I would never find one, thank you again for letting me know about this!
Mark

:Hi Mark
:
: No problem with 12UP4A (metal)(12D) and 12LP4 (12N).. Both actually have the same basing. The other side connection on 12N is just a coating on outside of the tube. This needs to be grounded and acts as a capacitor from high voltage to ground. Before this coating was used a 500 pf @ 20,000 volts was added for filtering.
:
: To change over connect HV to anode connector on 12LP4 and ground the outside coating. 12LP4 is much safer as 12UP4A is a metal tube with high voltage on the shell.
:
:Norm
:
:::Hi Mark
:::
::: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
:::
:::Norm
:::
::::Hi All
:::: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
::::Mark
::Hi Norm
:: The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
::Mark
::Hi Norm
One other question, there is a permanent magnet attached too the neck of the old CRT via of a spring clip, in looking at the SAMS for it, it says something about adjusting this for a minimum Green Glow in the neck for the CRT, I assume I will need to place this on the neck of the replacement CRT and follow the steps for reducing this Green Glow in the neck of it as well, could you elaborate on this for me, exactly what is this used for?
Mark

Hi Mark

Sounds like an ion trap magnet? The 12LP4 is made to operate with a double magnet where 12UP4A single magnet.

Even though a 12LP4A is supposed to use a double magnet should be able to use the single. I did this years ago on 10BP4's.

Adjust this magnet for brightest picture. This magnet directs the beam to your screen. Green is noticed when a beam hits eadges of the tube rather than screen.

There will be some mounting differences between these tubes but can be made to work. Overall size and electrical characteristics are about the same.

Norm

::Hi Mark
::
:: No problem with 12UP4A (metal)(12D) and 12LP4 (12N).. Both actually have the same basing. The other side connection on 12N is just a coating on outside of the tube. This needs to be grounded and acts as a capacitor from high voltage to ground. Before this coating was used a 500 pf @ 20,000 volts was added for filtering.
::
:: To change over connect HV to anode connector on 12LP4 and ground the outside coating. 12LP4 is much safer as 12UP4A is a metal tube with high voltage on the shell.
::
::Norm
::
::::Hi Mark
::::
:::: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
::::
::::Norm
::::
:::::Hi All
::::: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
:::::Mark
:::Hi Norm
::: The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
:::Mark
:::Hi Norm
: One other question, there is a permanent magnet attached too the neck of the old CRT via of a spring clip, in looking at the SAMS for it, it says something about adjusting this for a minimum Green Glow in the neck for the CRT, I assume I will need to place this on the neck of the replacement CRT and follow the steps for reducing this Green Glow in the neck of it as well, could you elaborate on this for me, exactly what is this used for?
:Mark
:

:Hi Mark
:
: Sounds like an ion trap magnet? The 12LP4 is made to operate with a double magnet where 12UP4A single magnet.
:
: Even though a 12LP4A is supposed to use a double magnet should be able to use the single. I did this years ago on 10BP4's.
:
: Adjust this magnet for brightest picture. This magnet directs the beam to your screen. Green is noticed when a beam hits eadges of the tube rather than screen.
:
: There will be some mounting differences between these tubes but can be made to work. Overall size and electrical characteristics are about the same.
:
:Norm
:
:
:
:::Hi Mark
:::
::: No problem with 12UP4A (metal)(12D) and 12LP4 (12N).. Both actually have the same basing. The other side connection on 12N is just a coating on outside of the tube. This needs to be grounded and acts as a capacitor from high voltage to ground. Before this coating was used a 500 pf @ 20,000 volts was added for filtering.
:::
::: To change over connect HV to anode connector on 12LP4 and ground the outside coating. 12LP4 is much safer as 12UP4A is a metal tube with high voltage on the shell.
:::
:::Norm
:::
:::::Hi Mark
:::::
::::: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
:::::
:::::Norm
:::::
::::::Hi All
:::::: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
::::::Mark
::::Hi Norm
:::: The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
::::Mark
::::Hi Norm
:: One other question, there is a permanent magnet attached too the neck of the old CRT via of a spring clip, in looking at the SAMS for it, it says something about adjusting this for a minimum Green Glow in the neck for the CRT, I assume I will need to place this on the neck of the replacement CRT and follow the steps for reducing this Green Glow in the neck of it as well, could you elaborate on this for me, exactly what is this used for?
::Mark
::Hi Norm
Thanks for the additional info! can hardly wait to get this new tube in here, its the last part of the restoration, everything else is done and working, this old Zenith Radio/Phono, TV should be quite a show piece when this is completed!
Mark

::Hi Mark
::
:: Sounds like an ion trap magnet? The 12LP4 is made to operate with a double magnet where 12UP4A single magnet.
::
:: Even though a 12LP4A is supposed to use a double magnet should be able to use the single. I did this years ago on 10BP4's.
::
:: Adjust this magnet for brightest picture. This magnet directs the beam to your screen. Green is noticed when a beam hits eadges of the tube rather than screen.
::
:: There will be some mounting differences between these tubes but can be made to work. Overall size and electrical characteristics are about the same.
::
::Norm
::
::
::
::::Hi Mark
::::
:::: No problem with 12UP4A (metal)(12D) and 12LP4 (12N).. Both actually have the same basing. The other side connection on 12N is just a coating on outside of the tube. This needs to be grounded and acts as a capacitor from high voltage to ground. Before this coating was used a 500 pf @ 20,000 volts was added for filtering.
::::
:::: To change over connect HV to anode connector on 12LP4 and ground the outside coating. 12LP4 is much safer as 12UP4A is a metal tube with high voltage on the shell.
::::
::::Norm
::::
::::::Hi Mark
::::::
:::::: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
::::::
::::::Norm
::::::
:::::::Hi All
::::::: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
:::::::Mark
:::::Hi Norm
::::: The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
:::::Mark
:::::Hi Norm
::: One other question, there is a permanent magnet attached too the neck of the old CRT via of a spring clip, in looking at the SAMS for it, it says something about adjusting this for a minimum Green Glow in the neck for the CRT, I assume I will need to place this on the neck of the replacement CRT and follow the steps for reducing this Green Glow in the neck of it as well, could you elaborate on this for me, exactly what is this used for?
:::Mark
:::Hi Norm
: Thanks for the additional info! can hardly wait to get this new tube in here, its the last part of the restoration, everything else is done and working, this old Zenith Radio/Phono, TV should be quite a show piece when this is completed!
:Mark
Hi Norm
I've been thinking about what you said about mounting differences, could you tell me or give me an idea what you meant and what I'll be up against?
Mark

Hi Mark

Need to wait until you receive the new tube. The original had a metal shell connected to high voltage. Your replacement, although the same size, will be all glass. Need some sort of band around the tube to mount it.

Electrically an anode connecter with high voltage wire needs to be added. Outside coating of your replacement tubes needs to be grounded. This can usually be done by a spring between chassis and the tube. Maybe grounding a band around the tube will be enough.

An interesting project.

Norm

:::Hi Mark
:::
::: Sounds like an ion trap magnet? The 12LP4 is made to operate with a double magnet where 12UP4A single magnet.
:::
::: Even though a 12LP4A is supposed to use a double magnet should be able to use the single. I did this years ago on 10BP4's.
:::
::: Adjust this magnet for brightest picture. This magnet directs the beam to your screen. Green is noticed when a beam hits eadges of the tube rather than screen.
:::
::: There will be some mounting differences between these tubes but can be made to work. Overall size and electrical characteristics are about the same.
:::
:::Norm
:::
:::
:::
:::::Hi Mark
:::::
::::: No problem with 12UP4A (metal)(12D) and 12LP4 (12N).. Both actually have the same basing. The other side connection on 12N is just a coating on outside of the tube. This needs to be grounded and acts as a capacitor from high voltage to ground. Before this coating was used a 500 pf @ 20,000 volts was added for filtering.
:::::
::::: To change over connect HV to anode connector on 12LP4 and ground the outside coating. 12LP4 is much safer as 12UP4A is a metal tube with high voltage on the shell.
:::::
:::::Norm
:::::
:::::::Hi Mark
:::::::
::::::: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
:::::::
:::::::Norm
:::::::
::::::::Hi All
:::::::: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
::::::::Mark
::::::Hi Norm
:::::: The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
::::::Mark
::::::Hi Norm
:::: One other question, there is a permanent magnet attached too the neck of the old CRT via of a spring clip, in looking at the SAMS for it, it says something about adjusting this for a minimum Green Glow in the neck for the CRT, I assume I will need to place this on the neck of the replacement CRT and follow the steps for reducing this Green Glow in the neck of it as well, could you elaborate on this for me, exactly what is this used for?
::::Mark
::::Hi Norm
:: Thanks for the additional info! can hardly wait to get this new tube in here, its the last part of the restoration, everything else is done and working, this old Zenith Radio/Phono, TV should be quite a show piece when this is completed!
::Mark
:Hi Norm
: I've been thinking about what you said about mounting differences, could you tell me or give me an idea what you meant and what I'll be up against?
:Mark

:Hi Mark
:
: Need to wait until you receive the new tube. The original had a metal shell connected to high voltage. Your replacement, although the same size, will be all glass. Need some sort of band around the tube to mount it.
:
: Electrically an anode connecter with high voltage wire needs to be added. Outside coating of your replacement tubes needs to be grounded. This can usually be done by a spring between chassis and the tube. Maybe grounding a band around the tube will be enough.
:
: An interesting project.
:
:Norm
:
::::Hi Mark
::::
:::: Sounds like an ion trap magnet? The 12LP4 is made to operate with a double magnet where 12UP4A single magnet.
::::
:::: Even though a 12LP4A is supposed to use a double magnet should be able to use the single. I did this years ago on 10BP4's.
::::
:::: Adjust this magnet for brightest picture. This magnet directs the beam to your screen. Green is noticed when a beam hits eadges of the tube rather than screen.
::::
:::: There will be some mounting differences between these tubes but can be made to work. Overall size and electrical characteristics are about the same.
::::
::::Norm
::::
::::
::::
::::::Hi Mark
::::::
:::::: No problem with 12UP4A (metal)(12D) and 12LP4 (12N).. Both actually have the same basing. The other side connection on 12N is just a coating on outside of the tube. This needs to be grounded and acts as a capacitor from high voltage to ground. Before this coating was used a 500 pf @ 20,000 volts was added for filtering.
::::::
:::::: To change over connect HV to anode connector on 12LP4 and ground the outside coating. 12LP4 is much safer as 12UP4A is a metal tube with high voltage on the shell.
::::::
::::::Norm
::::::
::::::::Hi Mark
::::::::
:::::::: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
::::::::
::::::::Norm
::::::::
:::::::::Hi All
::::::::: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
:::::::::Mark
:::::::Hi Norm
::::::: The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
:::::::Mark
:::::::Hi Norm
::::: One other question, there is a permanent magnet attached too the neck of the old CRT via of a spring clip, in looking at the SAMS for it, it says something about adjusting this for a minimum Green Glow in the neck for the CRT, I assume I will need to place this on the neck of the replacement CRT and follow the steps for reducing this Green Glow in the neck of it as well, could you elaborate on this for me, exactly what is this used for?
:::::Mark
:::::Hi Norm
::: Thanks for the additional info! can hardly wait to get this new tube in here, its the last part of the restoration, everything else is done and working, this old Zenith Radio/Phono, TV should be quite a show piece when this is completed!
:::Mark
::Hi Norm
:: I've been thinking about what you said about mounting differences, could you tell me or give me an idea what you meant and what I'll be up against?
::Mark
Hi Norm
Well too give you and idea, the original tube is mounted via of the chassis, in other words its attached too the chassis itself via of a metal mounting bracket on the bottom of the tube and a plastic shrowd that encircles the entire tube, the neck is supported by a metal bracket on the chassis, I hope this gives you and idea of how the original tube is mounted, and I hope this does not change anything, I do not know what is underneath the plastic shrowd, maybe a metal band on the tube I will find out when I remove the old one, will let you know.
Mark

:Hi Mark
:
: Need to wait until you receive the new tube. The original had a metal shell connected to high voltage. Your replacement, although the same size, will be all glass. Need some sort of band around the tube to mount it.
:
: Electrically an anode connecter with high voltage wire needs to be added. Outside coating of your replacement tubes needs to be grounded. This can usually be done by a spring between chassis and the tube. Maybe grounding a band around the tube will be enough.
:
: An interesting project.
:
:Norm
:
::::Hi Mark
::::
:::: Sounds like an ion trap magnet? The 12LP4 is made to operate with a double magnet where 12UP4A single magnet.
::::
:::: Even though a 12LP4A is supposed to use a double magnet should be able to use the single. I did this years ago on 10BP4's.
::::
:::: Adjust this magnet for brightest picture. This magnet directs the beam to your screen. Green is noticed when a beam hits eadges of the tube rather than screen.
::::
:::: There will be some mounting differences between these tubes but can be made to work. Overall size and electrical characteristics are about the same.
::::
::::Norm
::::
::::
::::
::::::Hi Mark
::::::
:::::: No problem with 12UP4A (metal)(12D) and 12LP4 (12N).. Both actually have the same basing. The other side connection on 12N is just a coating on outside of the tube. This needs to be grounded and acts as a capacitor from high voltage to ground. Before this coating was used a 500 pf @ 20,000 volts was added for filtering.
::::::
:::::: To change over connect HV to anode connector on 12LP4 and ground the outside coating. 12LP4 is much safer as 12UP4A is a metal tube with high voltage on the shell.
::::::
::::::Norm
::::::
::::::::Hi Mark
::::::::
:::::::: You can interchange CRT types as long as high voltage connected to the side terminal doesn't exceed rating of the one with a socket connection. List CRT numbers and we should be able to look up ratings.
::::::::
::::::::Norm
::::::::
:::::::::Hi All
::::::::: I'm trying to find a replacement CRT for the bad one I have, I've found several with of the right types as far as the Neck Pin connections are concerned, however the problem is all of them have the High Voltage Cap/Spring Clip type connections on the back of the CRT, the original one has a Metal Tab Connection on the back Rim of the CRT, what is the difference between the two and is there a way to sub one for the other without major ckt changes?
:::::::::Mark
:::::::Hi Norm
::::::: The original is a 12UP4A, the one I'm looking at is a 12LP4, let me know what I can do, thanks!
:::::::Mark
:::::::Hi Norm
::::: One other question, there is a permanent magnet attached too the neck of the old CRT via of a spring clip, in looking at the SAMS for it, it says something about adjusting this for a minimum Green Glow in the neck for the CRT, I assume I will need to place this on the neck of the replacement CRT and follow the steps for reducing this Green Glow in the neck of it as well, could you elaborate on this for me, exactly what is this used for?
:::::Mark
:::::Hi Norm
::: Thanks for the additional info! can hardly wait to get this new tube in here, its the last part of the restoration, everything else is done and working, this old Zenith Radio/Phono, TV should be quite a show piece when this is completed!
:::Mark
::Hi Norm
:: I've been thinking about what you said about mounting differences, could you tell me or give me an idea what you meant and what I'll be up against?
::Mark
Hi Norm
I got the new CRT Sat. I see what your talking about the metal coating of the shell of the CRT, what I'm going too do is get a dual wire type band strap at the hardware store and use this as a grounding strap around the CRT, then a wire between it and the ground on the chassis, that should do it, let me know what you think.
Mark