Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

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

Which way does it go?
#1

While waiting for a new transformer to show up, a previous thread caught my attention concerning the polarity of an electrolytic. I recently recapped my #18 but noticed I may have installed cap #55 incorrect. Could someone verify that positive on the cap should go to chassis ground and not the other way around? http://www.theoldradiofixerupperguy.com/...odel18.pdf

Thanks Don
#2

I thik Gnd should be positive. Your centertap is the rectifier's negative and is the most negative point in the whole pwer setup, the rest is positive relative to it, including Gnd that is onnected by a resistor.
#3


Agree with morzh. Positive end of cap 55 connects to chassis ground.
#4

Thanks guys. I was tossing this back and forth in my head when I was doing the recap. I had a 50/50 shot at it and I chose the wrong one. Will get it fixed and another problem solved. Thanks
#5

I thought from your post that you did connect positive to GND?

Here's how you can think of it: Unless you have another source of negative, the most negative point in your whole circuit is the negative of your rectifier. This is as negative as it will get. Now, the cap is decoupling the low value resistor's (this is usually the big powerful one with taps) leftmost point, the GND, towards the neg. of the rectifier. Whatever current flows through it, being sunk to the negative, it will create a positive potential on its other end, the GND, meaning that whatever it is there, it is positive towards the Rect. Negative.

Hence, PLUS of the cap is on the GND.

So, your




Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
The speaker table error?
G  10-1/2"       65, 76, 87, 95 Push-Pull 45's 2766 0.7 550 3200 H   10-1/2"    77, 96 Push-Pull...morzh — 09:26 PM
A Marconi model 86
I have a Stromberg, one of the early ones, seems early 30s. This is what I call a back breaker. None of the early Philc...morzh — 08:28 PM
A Marconi model 86
A backbreaker.....PaulPaul Philco322 — 08:12 PM
A Marconi model 86
>>What a behemoth! A Juggernaut.morzh — 07:47 PM
Philco 70 antenna lead
I am not sure I understood about the coils and the mush. I looked an more than one coil in 20, 70, 90, 60, Zeniths and ...morzh — 07:46 PM
A Marconi model 86
:e_biggrin: What a behemoth!  I hope the final result is as much a quality sounding example!  Keep us posted on your pro...GarySP — 07:32 PM
A Marconi model 86
I should add that the double conversion may only be used on the shortwave bands, but I haven't looked at the schematic t...Arran — 07:27 PM
Philco 70 antenna lead
Yes, that wire will not pick up much interference as routed - the RF at that level won't be affected, and if you have st...radio1 — 07:26 PM
Philco model 60
I'm also a member of MARC. Did you attend the Vintage Electronics Expo in Waterford, MI last month? That's where I got...GarySP — 07:22 PM
A Marconi model 86
Dan Double conversion is using two IF converters instead of one. This improves the image response. morzh — 07:15 PM

[-]
Who's Online
There are currently no members online.

>