20-07-2020, 01:45 PM
Definitely the case for the older valve 'scopes, but not the Tek or Philips.
The Philips is quite interesting as it can run from 24V DC. The PSU is a conventional 50Hz transformer, rectifier and smoother making a nominal 24V DC, and that is fed - via a DC input socket - into a switcher that generates all the internal rails, including the HV and EHT stuff. Being able to run from external DC is "potentially" quite useful. Also, some are Class II - all our PM3215s were, but our PM3217s are Class I (I'm not sure if that's official, or a mod). Class II operation is obviously useful when earth loops exist, but potentially a safety hazard... From the manual, Rob's PM3305 appears to be Class I.
The Tek is a conventional linear supply, making 100V and +/-8V.
All that notwithstanding, I would hope that Rob knows not to run these with the covers off, and definitely do not adjust anything inside.
The Philips is quite interesting as it can run from 24V DC. The PSU is a conventional 50Hz transformer, rectifier and smoother making a nominal 24V DC, and that is fed - via a DC input socket - into a switcher that generates all the internal rails, including the HV and EHT stuff. Being able to run from external DC is "potentially" quite useful. Also, some are Class II - all our PM3215s were, but our PM3217s are Class I (I'm not sure if that's official, or a mod). Class II operation is obviously useful when earth loops exist, but potentially a safety hazard... From the manual, Rob's PM3305 appears to be Class I.
The Tek is a conventional linear supply, making 100V and +/-8V.
All that notwithstanding, I would hope that Rob knows not to run these with the covers off, and definitely do not adjust anything inside.
