Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Chassis ground
#16

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?
#17

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
#18

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.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#19

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.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
IF can wire size and Rubber mounts?
Renovated Radios do carry what you need. As for the voltage, a wire should be at least 300V-rated.morzh — 11:13 PM
12' Philco
Andre the Giant got 2" on Kareem :lol:morzh — 11:11 PM
IF can wire size and Rubber mounts?
Thanks for the info but I doubt that a hardware store would be carrying the proper tuner assembly support mountings for ...georgetownjohn — 10:38 PM
12' Philco
Perhaps Kareem Abdul Jabbar?GarySP — 10:33 PM
My last cabinet for this year
Outstanding work, Dan! Take care and BE HEALTHY! GaryGarySP — 10:31 PM
My last cabinet for this year
They are a nice looking radio, Stromberg. I have a small tabletop octagon-dial one. It sounds surprisingly nice. And t...morzh — 09:40 PM
Philco 41-608 changer coupler
Different years but the same idea.morzh — 09:38 PM
My last cabinet for this year
That’s a beauty! :thumbup:klondike98 — 09:24 PM
Philco 41-608 changer coupler
Hi Morzh, I've searched using Mondial as the user name with various keywords such as 'coupler', 'motor', 'idler', 'p...alangard — 08:31 PM
Philco 16B Parts
I think the chassis is painted.morzh — 08:13 PM

[-]
Who's Online
There are currently 5276 online users. [Complete List]
» 1 Member(s) | 5275 Guest(s)
Avatar

>