I hope someone has a helpful hint on this. I have been unable to use a scope in repairing TO because the ground on my probe is either hot and draws sparks on the chassis or if I use DC ground it also won't work properly..IE I just see large AC on scope and can't see signals. Anyone have any experience in finding the proper way to get the scope lead ground at a level that will allow you to see the signals?? By the way, I am using a Tek 7633 scope. Thanks

:I hope someone has a helpful hint on this. I have been unable to use a scope in repairing TO because the ground on my probe is either hot and draws sparks on the chassis or if I use DC ground it also won't work properly..IE I just see large AC on scope and can't see signals. Anyone have any experience in finding the proper way to get the scope lead ground at a level that will allow you to see the signals?? By the way, I am using a Tek 7633 scope. Thanks

::I hope someone has a helpful hint on this. I have been unable to use a scope in repairing TO because the ground on my probe is either hot and draws sparks on the chassis or if I use DC ground it also won't work properly..IE I just see large AC on scope and can't see signals. Anyone have any experience in finding the proper way to get the scope lead ground at a level that will allow you to see the signals?? By the way, I am using a Tek 7633 scope. Thanks

The easiest way to work around this is to put the TO on an isolation transformer. This will allow you to put the scope's ground lead on the chassis of the radio.

If an isolation transformer is not available, just use caps in series with both leads for isolation (.01 to .05 should do), you will have some attenuation, but for circuit tracing and alignment, your results should be unaffected. You will not get an accurate flat DC reading, but the adequate yet imperfect filtering for tubes will not be much of a problem.

:::I hope someone has a helpful hint on this. I have been unable to use a scope in repairing TO because the ground on my probe is either hot and draws sparks on the chassis or if I use DC ground it also won't work properly..IE I just see large AC on scope and can't see signals. Anyone have any experience in finding the proper way to get the scope lead ground at a level that will allow you to see the signals?? By the way, I am using a Tek 7633 scope. Thanks
:
:The easiest way to work around this is to put the TO on an isolation transformer. This will allow you to put the scope's ground lead on the chassis of the radio.

Thanks to both of you for tip. The Isolation transformer has not worked so far. I have not tried a cap for isolation but I will give that a try and let you know. Sorry for delay in getting back, I was out of town. This particular TO is a challenge.
Aubrey

:If an isolation transformer is not available, just use caps in series with both leads for isolation (.01 to .05 should do), you will have some attenuation, but for circuit tracing and alignment, your results should be unaffected. You will not get an accurate flat DC reading, but the adequate yet imperfect filtering for tubes will not be much of a problem.
:
:
::::I hope someone has a helpful hint on this. I have been unable to use a scope in repairing TO because the ground on my probe is either hot and draws sparks on the chassis or if I use DC ground it also won't work properly..IE I just see large AC on scope and can't see signals. Anyone have any experience in finding the proper way to get the scope lead ground at a level that will allow you to see the signals?? By the way, I am using a Tek 7633 scope. Thanks
::
::The easiest way to work around this is to put the TO on an isolation transformer. This will allow you to put the scope's ground lead on the chassis of the radio.

Well the .01ufd Cap did the job. I can now signal trace. Thanks for help.
Aubrey
:Thanks to both of you for tip. The Isolation transformer has not worked so far. I have not tried a cap for isolation but I will give that a try and let you know. Sorry for delay in getting back, I was out of town. This particular TO is a challenge.
:Aubrey
:
::If an isolation transformer is not available, just use caps in series with both leads for isolation (.01 to .05 should do), you will have some attenuation, but for circuit tracing and alignment, your results should be unaffected. You will not get an accurate flat DC reading, but the adequate yet imperfect filtering for tubes will not be much of a problem.
::
::
:::::I hope someone has a helpful hint on this. I have been unable to use a scope in repairing TO because the ground on my probe is either hot and draws sparks on the chassis or if I use DC ground it also won't work properly..IE I just see large AC on scope and can't see signals. Anyone have any experience in finding the proper way to get the scope lead ground at a level that will allow you to see the signals?? By the way, I am using a Tek 7633 scope. Thanks
:::
:::The easiest way to work around this is to put the TO on an isolation transformer. This will allow you to put the scope's ground lead on the chassis of the radio.