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

Stewart Warner 176 assistance
#1

http://www.nostalgiaair.org/Resources/885/M0029885.htm

I recently bought this Stewart Warner 176 locally and just wanted to get a couple of items cleared up. I’m new to this and this radio has been worked on before which complicates it for me. The fellow I bought from said he was new as well and gave up on the restoration. 

R8 is 100,00 and R12 is 500,000. Are they are both potentiometers and if they are, how to measure them properly? Should they be replaced if they’re too high/low?

How would I find a value for R20, it measures 9.600K, I traced it back to a resistor on a large terminal board, it’s brown black but the multiplier has been scrapped off. Is 10K a reasonable value for this resistor. 

The last item is there is a remote volume control on the schematic. It didn’t come with one so is that an issue? I haven’t plugged this in yet and won’t until I finish with caps and resistors.
#2

R8 is the tone control and R12 is the volume control. R12 is the audio gain vs R19 control the gain of the rf amp tube. Generally I find that controls don't drift in value much unless there's a is a large amount of current passing thru them. This can cause heating which in turn can cause drift in the value. This isn't the case in this application.
But wear, dirt, and cracks in the resistive strip could be a problem. This will make it intermittent. Best way the check it is to use an analog ohm meter connected from the wiper to ground side of the control. The needle on the meter should move smoothly as the full range of the control is adjusted.

9.6K or 10K seem reasonable for R20. It supplies the screen voltage for the osc section of the 6A7. I might revisit it if the there is a problem getting the osc running.

On the remote volume control ground the white. That will restore the circuit so that the rf amp will work properly. Without doing so the rf amp is disabled and the sensitivity will suffer badly.

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




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
The thrill is gone again, thought I was close to being done with it. Well Friday it was receiving broadcast, Saturday mo...osanders0311 — 07:47 PM
Help with Supreme 599
Iam getting closer to fixing it. I bumped Up the tranny voltage to get 5v on the 80 tube. I gan get the needle to move ...daveone23 — 03:41 PM
Philco 42-345 Restoration/Repair
Hello RodB, Checking my previous post I realized you're the one with the 42-340. I replaced the string for the tuning...osanders0311 — 03:12 PM
5U4 vs 5Z4 tubes
I saw no evidence of anything going wrong. The transformer is fused already which is nice. Interestingly the 5z4 did...bridkarl — 02:37 PM
5U4 vs 5Z4 tubes
I doubt anything cooked in 30 seconds because of the oops! These are very similar tubes, and nothing but transformer re...GarySP — 02:30 PM
Restoration of the Canadian General Electric A-87
Paul Philco322.You will be keeping very busy, you may have to go back to work for a breakIcon_smile. Paul To rel...RadioSvit — 01:57 PM
5U4 vs 5Z4 tubes
I grabbed the wrong tube and put in a 5U4 tube instead of the 5Z4 - I just had the rectifier in with no other tubes. Af...bridkarl — 01:54 PM
Restoration of the Canadian General Electric A-87
After applying the filler to the entire body, I noticed that the shades of the facade and the side and top walls were ve...RadioSvit — 01:49 PM
Restoration of the Canadian General Electric A-87
You will be keeping very busy, you may have to go back to work for a break:). PaulPaul Philco322 — 01:46 PM
Restoration of the Canadian General Electric A-87
After removing the control knobs, chassis, dynamics and scale frame, I first started restoring the torn piece of veneer....RadioSvit — 01:20 PM

[-]
Who's Online
There are currently 863 online users. [Complete List]
» 1 Member(s) | 862 Guest(s)
Avatar

>