Allwave 23 sr#J497

[Thomas Day]

Hi All: I have posted about this set when I got it in 2015, and have some additional questions/information about it.
This appears to be an in-between version from the 5 knob set to the 7 knob set, in that it has the 2 antenna posts and the new antenna coupling system, but is a 5 knob set. The chassis has been much modified, and the chrome is in rough shape, so it would never be a display piece. I have been doing some work on it the last few days, and coming up with some questions, and figuring out what I would need to do to restore it electrically. Is there an available schematic for this? I can compare it with my current allwave 23, since it looks like most of the circuitry is the same or close enough. The good news is that aside from the modifications, most of the set is intact, and replacing the caps and some of the wiring that has deteriorated or been clipped off would be easy. I recapped my current 23, serial #K480, when I got it.
I do not have the power supply or speaker for this.
I was given an approximate production date when I posted the serial # in 2015.
I have also gained some insight into how it was built, all wiring first and components added next, and since I have done a lot of construction and repair over the years, this makes repair much easier.
Any other information anyone could add as to rarity or anything else would be appreciated. It may at some point play again.
Thanks
Thom

[Kent King]

Thom - There are only a couple known schematics for the AW23, I'm sure neither of them will cover this set precisely. I would suggest that if you go through it, follow the AW23 restoration guide that Norman wrote some years ago. If you spot areas of the set that differ significantly from the diagrams, sketch it out and we can add the information to the library. There is a note in the service literature that all sets above 500 have the new tuning condensers in the IFs. Does this set have them? The other complication is if the set was sent in for service, it may have been modified at that time - this makes building a timeline of changes even harder for us 85 years later...

[Thomas Day]

Kent:
Thanks for the reply. The modifications made to this set were not factory. Extra holes were drilled into the front of the chassis for extra controls, and I just found out that one section of the main power divider resistor is open. It had been moved, and the ground wire was left hanging loose.It does have the later version of IF trimmers, as does my allwave 23. The antenna system is shown and described in a 1936 Scott News, so this was built sometime around then. I do have copies of the early and late allwave 23 schematics, but the only difference there is the addition of the radio phono switch.
If I do decide to do a rebuild, I will follow them both. The coil can covers are frozen in place, so geting them loose will be a challenge. As for replacement power supply and amp, I have a tube amp from Hammond Organ Leslie speaker cabinets that have a balanced input and would work with this. They use quad 6L6 output tubes, and a DC supply for the chassis can be built. It did come with all tubes including the neon regulators, but several of the grid caps have come loose.
This has been set aside since I got it, so it will get attention as I get time. My main interest in getting this working is a comparison of performance with my early version 23. I need to do an enlargement of the schematics to get a better view of parts values and other data. I also have the service data info from this site, and have done work on my other AW23.
This will be a 'labor of love' for my own satisfaction of seeing another chassis saved from the scrap heap..
Thanks
Thom

[Thomas Day]

Hi all:
Thanks to the Scott info archives, I found the (a) schematic for the 7 knob version of the Allwave 23 that may closely correspond to the one I have. It has the antenna coupling system J-497 has. However J497 is a 5 knob version, since the beat oscillator switch is below the band switch, in the same place as my K-480 early version. Replacing the B+ divider could be a challenge, but available hi power resistors can be subbed in.
I have printed out 3 copies of the schematic in different sizes to get a better view of parts values and wire runs to use with this chassis, so maybe it will play again.
Thom

[Thomas Day]

Starting to work on J497 Allwave 23. One of the trimmers on one RF coil is missing. Parts info says it is a 100pf trimmer. I can find them, but just a question if that value is the total value and adjustable from there? Also the schematic lists a red w/yellow trace at B+120 volts, but no indication where it comes from or goes to.
This is a long term work in progress. It does have the later variable trimmer caps in the IF stages.
The schematic from this web site is dated May 12, 1936 and is for the 7 knob version, but J 497 is a 5 knob version with the later twin antenna posts and antenna coupler coil. Except for the phono switch, and antenna circuit, this is basically the same as the earlier Allwave 23 I have.
Thanks
Thom

[Kent King]

Thom -

I have lots of parts chassis, if you can send me a pic or indication of which trimmer you need, I can pull one off a parts chassis. Anything else you need too...just let me know. It's possible your set went back to the factory and got the IF trimmer update during service. It may show traits of both early and late AW23s. 

Kent 

[Thomas Day]

Hi Kent:
Thanks for the reply. I think this set is factory original, since modifying it to the later twin antenna system would be difficult at best. I found a source for the trimmer caps, but thanks for the offer. I also found a Pro Wire source for flexible rubber covered wire in several sizes and will use it to replace the deteriorated wiring. I was able to remove the coil covers and clean them up. All of the capacitors are original and will be replaced. I also got three power resistors to replace the B stick divider and will mount them on terminal strips. I will have the schematic blown up to 18X24 which will help a lot. Still not sure where the red/yellow wire comes from or goes to, since the colors are really faded out. It also has the filament bypass caps for the oscillator tube.
It does pain me a little to see these turned into parts sets, but I understand that not everything can be saved or restored easily. This one could easily become a parts set, but I love a challenge. This one seems to be a transitional set between early and late versions and as such is worthy of restoring.
Again thanks for the reply. I appreciate any and all comments and help anyone can provide.
Thom.

[Kent King]

Interesting...is the power resistor open? I've seldom seen a bad divider in the AW23 sets. I don't part our salvageable sets, the ones on my parts line are way too far gone - often, they were missing major parts when I picked them up. I have a bit of everything on the parts line - let me know if you need something.

Kent

Thomas Day said:

Hi Kent:
Thanks for the reply. I think this set is factory original, since modifying it to the later twin antenna system would be difficult at best. I found a source for the trimmer caps, but thanks for the offer. I also found a Pro Wire source for flexible rubber covered wire in several sizes and will use it to replace the deteriorated wiring. I was able to remove the coil covers and clean them up. All of the capacitors are original and will be replaced. I also got three power resistors to replace the B stick divider and will mount them on terminal strips. I will have the schematic blown up to 18X24 which will help a lot. Still not sure where the red/yellow wire comes from or goes to, since the colors are really faded out. It also has the filament bypass caps for the oscillator tube.
It does pain me a little to see these turned into parts sets, but I understand that not everything can be saved or restored easily. This one could easily become a parts set, but I love a challenge. This one seems to be a transitional set between early and late versions and as such is worthy of restoring.
Again thanks for the reply. I appreciate any and all comments and help anyone can provide.
Thom.

[Norman S Braithwaite]

Thom:

I use silicone rubber insulated test lead wire to replace the original rubber wire.  It is available in similar gauges of wire and diameters of insulation and will outlast other types of rubber.  Like Kent, I have many parts and parts chassis.  If Kent doesn't have parts you need, let me know.

Norman

Thomas Day said:

Hi Kent:
Thanks for the reply. I think this set is factory original, since modifying it to the later twin antenna system would be difficult at best. I found a source for the trimmer caps, but thanks for the offer. I also found a Pro Wire source for flexible rubber covered wire in several sizes and will use it to replace the deteriorated wiring. I was able to remove the coil covers and clean them up. All of the capacitors are original and will be replaced. I also got three power resistors to replace the B stick divider and will mount them on terminal strips. I will have the schematic blown up to 18X24 which will help a lot. Still not sure where the red/yellow wire comes from or goes to, since the colors are really faded out. It also has the filament bypass caps for the oscillator tube.
It does pain me a little to see these turned into parts sets, but I understand that not everything can be saved or restored easily. This one could easily become a parts set, but I love a challenge. This one seems to be a transitional set between early and late versions and as such is worthy of restoring.
Again thanks for the reply. I appreciate any and all comments and help anyone can provide.
Thom.

[Thomas Day]

Thanks Kent and Norman:
I found the silicon wire at a company called BNTECHGO in several different sizes and got 3 spools of #22, 24 and 20 in ten foot lengths. Very flexible. One of the 2400 ohm sections of the B stick divider is open, I will replace all 3 with 20 watt power resistors mounted to terminal strips. I also found the red/yellow wire, it runs from the neon tubes to the plate of the oscillator tube.
As far as major parts, this set is complete, so not so tough to restore. I have done a recap on my K 480 chassis when I got it, so this one will be easy. All of the tube sockets are held in with screws, so the covers can be removed and cleaned. All in all a nice winter project.
Again, thanks for all the replies and offered help. It is much appreciated.
Thom

[Thomas Day]

Working on J497 Allwave23 continues:

I am in process of rebuilding this chassis, and finding some differences between the schematic and actual parts used.  The screen resistors for the 39/44 tubes are listed as 1K on both the schematics I have for the early and late versions. The parts callout in the chassis photos call for 5K resistors and the chassis has 10K resistors.

Knowing that Scott made running changes in production, this shouldn't surprise me, but this is a pretty wide variation. The plate voltage is listed as 235 volts and the screen as 90 volts. These come from different sources, and screen current is minimal. So, replace with what I find, or follow the schematic. I have the schematic blown up to 2 feet by 3 feet and the component values are plainly visible.  Other values in the chassis pretty much conform to the schematic. Just another 'interesting' variation in custom production.

Thanks

Thom 

[David C. Poland]

My rule, if close inspection of solder joints and such so it looks original, stick with actual component values seen.

But, there is a Scott service bulletin stating during servicing to replace the many the 400 volt .1  caps with 600 volt .05 units, except those on the tone controls.

[Kent King]

I agree with Dave - I look closely at the set and if it appears to be original, I stay with what is there. Check the AW23 data in the Info Archive, there were several documented production changes described in the literature.

Kent