Chassis ground - Printable Version
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RE: Chassis ground - elfiself - 01-10-2018
Once again thank you Aaran, you have confirmed what I have worked out for myself. In fact I just traced out B- andB+ with a highlighter last week. I also enlarged the sch which helps a bit also. I have read that the coil on cap #7 can be eliminated as it was intended to reduce interference from some type of off shore signal bouys which are no longer in service. Any thoughts?
RE: Chassis ground - elfiself - 02-09-2018
Aaron I appreciate all your help. Looking at the Philco 42-pt7 schematic and tracing B-, it seems to go to the plate of the 50L6GT. There is however a connection to the primary of the OT ahead of the plate and the primary is connected to B+. Could you explain whats going on at this connection.
Thanks again
Larry
RE: Chassis ground - Radioroslyn - 02-09-2018
Hi Larry
>I have read that the coil on cap #7 can be eliminated
Yes you can.
> B-, it seems to go to the plate of the 50L6GT.
There is a connection from B- to the plate of the 50L6 (p 3) BUT it's thru #24 a .02mf cap. This doesn't actually short the B+ voltage across the primary. 24 is used for tone compensation it mutes the high frequency audio response.
RE: Chassis ground - jcassity - 02-11-2018
this is a pretty complicated subject to be honest, and its backed by lots of facts and theory.
the NEC integrated "grounded" and "Grounding" language into article 250 more intensly in 2014 than ever before.
the result is that the color and job of a Grounding conductor vs a Grounded conductor are muddled with confussion.
I looked at your diagram and here is my take on how to uncomplicate this .........
your 35z3....
components downstream (from power cord out into the depths of the diagram) depend on the 35z3 to be installed, they depend on it because things like caps, inductors or resistors are able to "REFER" or reference thier ability to work based on the 35z3 being opreationally ready and installed.
you have parts like item 5 or 7 as examples which could care less if the 35z3 is installed or not.
These guys "could" do a job if they had voltage because they have thier own dedicated chassis ground. technically these two items are still "in reference to" the power chord being present and the utility power being correct,, yet i would consider this as its commonly agreed as a "chassis" ground.
think of anything that depends on something else for power or ground as an item that is constantly "refering" to something else before it can do its job.
your car, technically its a constant floating ground. you dont need a ground rod steak to make it work. unto itself there are various "chassis" and "reference" ground applications.
your house power though will not work proper or at all if either the reference voltage(to your utility transformer) or the reference ground (your ground rod or utility ground) is faulty or open.
the NEC makes various attempts to clarify this yet they confuzzel many readers. the couple words like "bonding", & "grounding" in relation to topics that contradict thier "grounded" and "grounding" conductor profiles.
one thing you can try to visualize to see the importance of proper grounding .... vs bonding..
imagine using your meter and if it were possible you had leads that are 1000' long.
you insert your red meter lead into the "HOT" prong on a 120v outlet in your home.
you insert your black meter lead into the "HOT" 120v prong of your neighbors home a thousand feet away.
(^assumes your home is on a separate transformer than your neighbor)
what would you expect your meter to read?
~you would read something in a voltage range but its uknown, you certainly would not read zero, the odds of that are billions upon trillions to one.
even the outside plant power companies individual remote pole mounted step down transformers are constantly "refering" or referencing to something else, thats the planet earth, although in tech terms we would classify this as a "chassis" ground.
furthermore, without the sun, the earths reference would be zilch.
sorry , had to chime in....... hope it got you thinking.