"EH Scott Radio Laboratories was continuously making minor changes to component values. Phenolic outgasses and shrinks slightly with age.
Norman"
The Fine Things are Always Hand Made
John Stafford's Discussions
Problem with AW 23 Oscillator
Started this discussion. Last reply by Norman S Braithwaite Apr 9. 5 Replies 0 Likes
Nearing completion of restoration of my AW 23 7 knob.One significant problem remains. Something happens when tuning the lower frequencies on the red and green bands. As I tune towards the lower…Continue
AW 23 amplifier voltages low
Started this discussion. Last reply by John Stafford Apr 3. 5 Replies 0 Likes
I have finished replacing capacitors on my AW 23. Radio has been powered up and is working on all but the Green Band. Reception is okay but nothing to brag about.Now that it is working I started…Continue
AW 23 Band Selector Pointer Knob needed
Started this discussion. Last reply by Kent King Feb 12. 1 Reply 0 Likes
I am just starting restoration of an AW23 7 knob with Tasman cabinet.It looks like a very complete unit with the exception of the metal band selector pointer knob. Are there reproductions of this…Continue
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"Problem fixed. As Norman suggested there were poor connections to the stators on the tuning capacitor. There was no corrosion present. Over time the phenolic insulators had yielded to pressure from the screws allowing the screws to come loose. All 3…"
"I had a similar problem with mine, Oscillator finally quit. Tube was bad. Replaced it and seems to be fixed. I have a second chassis that I have totally rebuilt. Also, a service bulletin recommending a direct connection of cathode to ground and .05…"
"Thanks Norman. I will take a look at those items. I have not removed the tuner so far."
"Parasitic oscillation. Have you removed the tuner, loosened and re-tightened the screws holding the solder lugs to the stator sections? If not, resistance in the machine screw connections to the stators is a likely cause. Another…"
Problem with AW 23 Oscillator
Nearing completion of restoration of my AW 23 7 knob.One significant problem remains. Something happens when tuning the lower frequencies on the red and green bands. As I tune towards the lower frequencies on these bands something happens to the oscillator circuit. Reception goes quiet after a big noise (loud pop) and enough current is being drawn that the neon regulator bulbs go dark. My scope shows that the oscillator is still running.Not sure if it is still on the correct frequency…See More
"I have located two problems resulting in low voltage readings. My testing was done with a line voltage of 112 VAC per the Technical Service Data document. I measured this at the AC plug. What I found was that there was excessive voltage drop across…"
"Yes there are some 25 cycle Scott radios. They have an oversized power transformer (because additional iron mass is needed)., sometimes big black metal box instead of the chrome housing. No problem using a 25 cycle radio on 60 cycle power.
Use a…"
"John, I thought I would chime in...Maybe Kent could tell us if this is a possibility ...did Scott build power supplies for 25 cycle use? Could that be the issue with the differences in voltages and the fact your transformer only runs warm to the…"
"Thanks Kent.
Line voltage at my house is reliably between 120VAC and 123VAC. I use a variac on the bench to set voltage as necessary for testing.
It is great to have typical current draw for the tuner B+, I will definitely check that.
I will…"
"John -
That is interesting, with today's high line voltages, I always use the "Hi" setting and still have voltages near the top of the acceptable range. What is your local line voltage (mine is usually around 123VAC)?
Check the…"
AW 23 amplifier voltages low
I have finished replacing capacitors on my AW 23. Radio has been powered up and is working on all but the Green Band. Reception is okay but nothing to brag about.Now that it is working I started checking voltages and have found most of the readings for the Amplifier are 10 to 20% low. The Service Data shows expected voltage readings while specifying a line voltage of 112 Volts. The document does not indicate which position the Hi/Low switch should be in but since the specified Voltage is >…See More
"I am in the process of rebuilding a 7 knob AW-23 and have also found .05uF Sprague capacitors in all of the locations shown on the schematic as .1uF. It would seem that I need a different version of the schematic. So far I have been unable to locate…"
"I expected that having two members with the same name would cause confusion at some point. I am a new member with an AW-23 7 knob SN W-621 in a Tasman cabinet. I believe that the Philharmonic belongs to an older member, now deceased, with the same…"
"As I continue my restoration I find a capacitor that I don't see on any of the AW23 chassis pictures. I have not found it on the schematics either. In any case I enclose a picture of the part which has a date stamp on it that is a bit hard to…"
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