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

Fisher Custom Electra hum issue
#9

>Any recommendations on a more permanent filter solution?

I'm glad you asked that... [Image: http://philcoradio.com/phorum/images/smi...on_lol.gif]
A couple of things come to mind. On some of the older FM sets the fm ant is connected the ac line thru a small value cap. At rf frequencies this cap looks like a short and couples all the noise that's on the line into the rf amp stage. So if your set has this configuration removing that cap would help.
More of an experimenter than a break out the slide rule and calculate kind of guy. If that being said I think something that looks like this may be  helpful:    
In terms of turns would start with about 5 and perhaps up to 20 choosing the number that give the best attenuation. You can also try connecting a wire from chassis ground to earth ground. This is made simple if you have hot water baseboard heat. You can just clip the ground ware on the one of the heater fins. Using the 3rd wire on the outlet isn't a good idea as you'll probably find more noise there. I'm sure there's someone smarter than I that has some better ideas.

GL

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


Messages In This Thread
Fisher Custom Electra hum issue - by patrician56 - 03-12-2018, 09:28 PM
RE: Fisher Custom Electra hum issue - by TV MAN - 03-13-2018, 08:52 AM
RE: Fisher Custom Electra hum issue - by Radioroslyn - 03-13-2018, 06:03 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Need to purchase some accessories for restoration of my Old Philco Radio
Here is a list of resources found in our online library that you might find useful. Mike's Gobs of Knobs email addres...klondike98 — 01:46 PM
First Radio restoration
Hi Tubeman, Welcome to the Philco Phorum.  Phamily Phriendly Pfun with Phine Pholks Phull of Philco Phacts. (See a p...MrFixr55 — 12:33 PM
First Radio restoration
You could post in the WANTED ADs section here on the Phorum and see if anyone has an RF generator that they want to sell...klondike98 — 11:55 AM
Zenith H725
Good ideas, thank you Arrange and Rich. I have the adhesive aluminum foil already and can try that immediately. More ...EdHolland — 10:18 AM
Graphics for majestic 1050 dial glass.
Murf; I found this thread on the ARF, the first photo has a pretty good view of the dial glass. Regards ArranArran — 01:12 AM
Zenith H725
hello Ed, how about that speacial tape used for ducting it's like foil or how about thin piece of aluminum roof flash...radiorich — 12:19 AM
Zenith H725
Ed; One material that I have seen, but never tried for this was material for making exhaust gaskets, it's similar to ...Arran — 11:42 PM
Zenith H725
I just remembered, I have some hi temp silicone rubber material which could do the trick. Or a piece of FR4 laminate. Th...EdHolland — 08:39 PM
Zenith H725
The PSU filter cap arrived today (thank you USPS!) so I will work on that later. Meanwhile, I have the dial, speaker...EdHolland — 06:42 PM
Philco 610B oscillator wiring
Thanks Terry. After checking my notes I think I recorded about -10v at the 6A7 G4/control grid. The screen grid (G3 &...Tubester — 05:59 PM

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

>