Allwave 23 dial scale.

[Thomas Day]

I have posted a photo of the dial scale of my allwave 23 showing the location of the indicator bar. Calibration is off by about .25 inch on all bands. Hope this is a simple mechanical adjustment. 

Is the  indicator bar in the right place?

Thanks

Thom

[Norman S Braithwaite]

Thom:

The indicator shadow looks a little high in the window.  You should be able to lower the indicator shadow by rotating the lamp back.  Then, when aligning the receiver, the dial scale needs to be rotated such that the indicator shadow matches the line at the bottom of all bands.  Also, I am not seeing the tuning meter needle shadow.

Norman

[Thomas Day]

 

The tuning meter does show up, but is only about 3/8th inch long. I will try adjusting the lamp. Also I haven't attempted to clean the dial scale or the window. I had a bad experience with another radio, in that I managed to wipe out part of the dial. 

Thanks for the information.

Thom

[Norman S Braithwaite]

3/8-inch is on the long side for the shadow of the tuning meter needle.  The shadow of the tuning meter needle on most of my sets is closer to 1/4-inch.  Some Scott dials can be very carefully cleaned but unless you have a Plan B, you may not want to take the chance.  I have uploaded a high resolution scan of an NOS AW-23 dial scale to this site in hopes of someone reproducing it on material similar to the original.  I know that others have photocopied to thinner clear acetate or something of that sort but I have yet to hear from someone making a faithful reproduction.

Norman

[Thomas Day]

Thanks Norman:

the tuning meter shadow is closer to .25 inch. I reset the pilot lamp a little further back and it did lower the bar shadow. Dial scale is closer now. Still doing research on an outside antenna, but it is working ok connected to our DTV antenna in the attic.

Thom

[Norman S Braithwaite]

Thom:

The entire range of frequencies for which your DTV antenna is designed is way, way above the highest frequencies capable of being received by the Scott AW-23.  The DTV antenna is not providing any help!  The wire leading to your DTV antenna is acting as the antenna.

Norman

Thomas Day said:

Thanks Norman:

the tuning meter shadow is closer to .25 inch. I reset the pilot lamp a little further back and it did lower the bar shadow. Dial scale is closer now. Still doing research on an outside antenna, but it is working ok connected to our DTV antenna in the attic.

Thom

[Thomas Day]

Follow up to dial scale calibration.

The scale is off by a great margin at the bottom of the dial. This looks like it should be a mechanical reset of the dial to put the indicator bar at the bottom of the Kil-Meg lettering when at the bottom of the dial as per the service info. The center calibration seems to be pretty close as is, but will be off by quite a bit when I reset the dial. I have no way to know if anyone has tried to re-calibrate the radio, but all bands seem to be off by about the same amount. The indicator bar is about one  quarter of the way down from the top of the dial as per the photo posted earlier.

Thom 

[Kent King]

Thom - it does sound like someone may have "aligned" the set sometime in the past, and may not have done it correctly. As with most sets, there are padder adjustments for the low and high ends of each band. The fact that they are <all> off may mean some other common adjustment is off, perhaps the IF. There wasn't a hard and fast IF standard in 1935-36, if a recent restorer did not know better, they might have adjusted the set to 455 or other equally incorrect value. I would certainly consider realigning the set, per the Scott instructions.

Kent

[Norman S Braithwaite]

OK, I have to confess confusion to which I have contributed.  When I referred to the bottom of each band, I was referring to the low frequency end of each band.  This happens to be physically at the top end of the dial scale as it appears in the window.  If we are all referencing the frequency metric when we state "bottom end of the dial", we are all on the same wavelength (yes, the pun is intended)!  If not, the dial scale should be adjusted such that the shadow of the station indicator corresponds with the horizontal line at the low frequency end of the scales (physically the top of the dial as it appears in the window).  Then RF adjustments may be made.  Misalignment of the IF will not affect where stations are received with respect to the dial markings.  If stations are off by the same rotation for all bands, the first thing I would look at is the tuning capacitor.  Make sure it is able to rotate the full 180-degrees (no interference by other components).  Second, I would make sure that all stator and rotor plates feeding the converter stage are making good contact (less likely problem), then look for other systemic problems.  The symptoms described are indicative of the receiver being aligned with a problem in the tuning circuit feeding the converter stage (do try another converter tube in the unlikely case that the one being used has an unusual problem).  Hopefully the problem is not due to someone having tampered with the tracking adjustment (end plates of rotor sections) but it may well be the case.  If so, I have other tuners you may try substituting into the chassis.

Norman

[Thomas Day]

Kent and Norman:

Thanks for the replies. I do indeed mean the low frequency end of the dial. The indicator bar is about 3/8" below the top edge of the escutcheon, with the line under the kil-meg about .25" below that with the dial all the way at the low end.

Comparing frequencies with a digital tuner, 560 comes in at 570 on the dial, 720 is just about dead on, 780 is a little above that, 1000 is about dead on, 1450 shows up at about 1420 and 1490 shows up at about 1460 on the dial.

On the next blue band, stations above 1500 show up well above the beginning of the scale.

It would appear that physically adjusting the dial scale would put the top end of the  scale close and the low end off even more. 

The dial is free to rotate completely from end to end.

I haven't taken the cover off of the tuning cap to check it. I can also try new converter, RF and oscillator tubes as well. 

Thanks

Thom

[Norman S Braithwaite]

Thom:

Those deviations are within the range of adjustment.  Since adjustment of the low frequency end of the shortwave bands consists of physically spreading the windings of the coils, the best approach is to loosen the set screws on the dial mechanism and rotate the dial mechanism on the tuner shaft such that the stations at the low frequency end of the shortwave bands tune in correctly.  Then tune to the high frequency end of each band and adjust trimmers such that stations at the high frequency end of the band tune in correctly.  Recheck the low frequency end of the band.  If the set was way out of alignment, as appears may be the case, the procedure may need to be repeated.  Finally, if not all bands are correct to your satisfaction at the low frequency end, you can consider tampering with the windings per Scott instructions.

Norman