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

37-630T Volume Control
#1

The schematic shows this radio using a 2 megohm volume control with a 1 meg center tap. I measure the resistance between the two outer lugs and I see 3 megohms on my meter. When I measure between the center and an outer lug I see 1.5 megohms and it goees down to .7 meg with the control all the way clockwise (full volume) position.
is this poteniometer ok ?  While cleaning the track I noticed one spot that appears rough while the remainder is smooth.
#2

With the shaft facing towards you and the 3 closest terminals pointing downward. Connect your ohm meter to the two terminals to the left. With the shaft turned all the way ccw you should read pretty close to 0 ohms (shorted). This is typically were most of the wear happens and is the failing point. Turn the shaft cw so it is in the half way position and you should read about 10% of the total resistance in your case 300K. With the shaft turned full cw should read the full resistance of 3M. Best to use an analog meter as worn spots with cause the needle to jump around.

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
#3

With the shaft all the way ccw I don't get zero ohms, I'm reading 99 ohms. All the way cw I get 3.1M. On the analog meter the needle moves smoothly. Should I replace this control ?
#4

You almost never get 0 ohm. 99 ohm is very good.

As for 3M i/o 2M, I'd test it befor getting it condemned: it is likely to work.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.




Users browsing this thread:
[-]
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.

>