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
38-10T chassis Restoration begins
Hello Dan, Very cool !! morzh , I have seen people put computers and other items in the dish washer ! Sincerely Ri...radiorich — 11:26 PM
38-10T chassis Restoration begins
Arran I also washed tuning caps in dishwasher and in soap water without having removed the micas. Upon drying, it wa...morzh — 02:00 PM
38-10T chassis Restoration begins
Hi Richard, I used to build houses and we used a lot of those gold flake counter tops. We even used gold flake ceramic t...dconant — 11:11 AM
38-10T chassis Restoration begins
Hello Guys, Don't mind my 1950s kitchen countertop and funny thing about that countertop it has little what looks like ...radiorich — 10:53 AM
38-10T chassis Restoration begins
Hello Dconant, Very funny but here is Photo of my Gemoro ultrasonic cleaner ! Arran , I have not had any issues eith...radiorich — 10:48 AM
Philco 60 Squealing
Radio is playing right now and sounding good.dconant — 08:54 AM
38-10T chassis Restoration begins
I don't think it is as critical as some would think. I've washed chassis, typically on hot days during the summer time, ...Arran — 07:51 AM
Rusty Tuning Condenser
I would try something like Evaporust, or a similar product, there is a guy on Y.T that does this with aluminum fined tun...Arran — 05:14 AM
Rusty Tuning Condenser
Be careful with aluminum vane caps. I did that, with dishwasher; it dulled the whole thing, which became grey. No, no,...morzh — 10:19 PM
Rusty Tuning Condenser
Hello Rob. I've also heard of soaking the tuning cap in automatic transmission fluid. This was an old trick we used to...GarySP — 06:14 PM

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

>