1934 AW 15 Electrical Restoration, Questions Please

[Jon Ketron]

Hello all,

I am new to this forum and somewhat new to E.H. Scott Radios.  I have about 10 years experience collecting, restoring, and rebuilding pre WWII radio's back to factory specs., or as close as possible.  I am excited to start an electrical restoration on this early version AW15.  My goal is to re-stuff each and every bathtub style capacitor which will include drilling out each rivet and re-installing new rivets.  I will also re-stuff all electrolytic cans.  The end goal of this restoration is to have an electrically restored factory looking set.  

Has anyone re-stuffed these bathtub style caps before?  Could you please give me any pointers or advice for this procedure?  What style of rivets are used for re-installation and what would be the best tool to use for this as there will be many awkward angles?

You may notice the Olympian cabinet this radio resides in has short legs.  Upon close examination, Norman and myself have decided this cabinet had a new set of legs and stretcher installed at some point during the radio's life.  Whether at the beginning or sometime mid point, I don't know.  The legs and stretcher look to be a custom job and the quality shows as this modification looks to be neat and very difficult to spot upon preliminary inspection.

I would like to thank all of you for any help provided, this looks to be an excellent forum!

Thanks,

Jon

 

[mike hadley]

Jon,
When you make your resistors use more than one resistor in the new one, this will spread the dissipation and get the working voltage up.
Also you will find that when you fill the mould with epoxy it's a fine line between too much and not enough, too much and you will get a fat resistor, not enough and you will get voids.
The reason that I did not use metal filled putty for the resistors is that I was worried about the ht across the finished item,
It may be of interest that I am about 2/3 the way through restoring my allwave fifteen, so far new psu transformer, new caps in the psu, made new voice coil for speaker, fitted new cone to speaker, half way through stuffing bathtubs.
Still lots more to do.
Mike

[Jon Ketron]

Mike, thank you for the pointers, will do.  Sounds like your AW15 project is coming along well.  I have come across many radio brands and pre WWII circuitry layouts during my decade of radio collecting and restoration.  Nothing really comes close to EH Scott.  I have come to truly appreciate this brand of radio.  The quality and craftsmanship are unmatched by most manufactures of this time period.  These radio's truly deserve top notch restoration work such as what you are doing and many others here on the forum have or are currently doing as well.

More to come soon on this restoration.

Thanks

Jon

[mike hadley]

John,

I have just been restuffing the large bathtub caps in my aw15, the ones on the rear of the chassis where the cable comes in, the two marked 1/10 mmfd 200v are in fact LC filter networks, inductor across the terminals and 0.1uf to ground, I have attached a photo, the caps are the ones marked with a red dot of paint, this terminal is the junction of the coil and cap.

be careful when you dismantle these etc etc.

Mike

[mike hadley]

Photo of inside filter, under the tin cover is a wax paper and pitch, if you carefully dig around you will find the cap and inductor,cap is to the left in the picture. Cap is easy to replace 0.1uf 1000v axial Polypropylene fits nicely.

Mike

[Jon Ketron]

Mike, thank you for the info and pictures.  I have been studying the schematic and parts list for the tuner chassis, gathering a parts list as we speak.  If I am correct, your picture shows bathtub number 91, 92, and 93.  I noticed on the parts list numbers 92, 93, 94 are all bathtub's containing both choke and condenser in each as you show above.  All three: #92, 93, 94 containing the inductors are 0.1 MFD correct?  The parts list does not show the capacitor value.

One thing to mention.  I prematurely decided to re-stuff this AW 15.  It has been decided to not re-stuff as I am performing this restoration for a friend/customer.  I do own an AW 23 that I will re-stuff to a "T".  All this info does help a lot and will be applied to that restoration down the road!  Fear not, as I will continue this topic with a finished product for all those interested.  You all have been a great help thus far, thank you.

Parts are now in for the AMP Chassis, will be posting this section of the restoration here in the next few days.

Thanks

Jon

[mike hadley]

John,

The filter caps are 0.1uf.

The large bathtubs are filters except the 1/2mfd one, nearest the bfo adjuster,

my aw15 has only two hence the homemade wax cap, this 'filter' has a coil bolted to the chassis with a 0.1uf to ground from the first if screen grids,

I have a copy of the chassis underside drawing, and I have identified all of the major components ie. tubes caps locations etc, I plan to update this via photoshop and post a copy, I'll try to do this over the weekend.

you have an allwave 23, I'm green with envy, a real belter of a set, never seen one but if its anything like the aw15...

Mike

[Jon Ketron]

Thanks Mike for the clarification on the caps in question.  I have been polishing on the power amp chassis.  Despite it's pitting, the chrome looks decent.  Please keep me posted on your underside drawing.  I do have an AW23 which resides in a standard Waverly cabinet.  The chassis is the small window 7 knob version and has good chrome.  This set was never ordered with the high frequency tweeters.  I plan on adding this expensive option down the road.  A friend has offered to sell me an expander unit.  Depending on it's condition I might buy it off him to make the AW23 an AW27.  For another topic down the road.

I have heard from others the AW15 sounds great.  I could only imagine what an AW23 would sound like.  Overall performance of the AW23 would be astounding.  The AW15 commands a lot of respect in my book, far superior to just about any manufacture of the time period and I have been through many pre 1935 AM circuits during my decade of collecting.  What an unbelievable company!

Jon

[David C. Poland]

Jon - FYI - The AW-27 variant of the AW-23 is not made by adding the optional outboard volume expander.

Rather, the 27 tube AW-27 has the expander circuit installed on the receiver chassis, the pair of audio drivers are relocated on to an extra long Amp chassis and the receiver sports a pair of magic eyes - one for tuning indicator and the other for the degree of expander action. And there are 2 additional controls flanking the usual controls, one for control of the expander circuit and the other for the BFO instead of the button under the the band switch. The AW-27 escutcheon set is usually bright gold rather than darker bronze color.

For a visual reference of the AW-27 panel configuration, go to Archives - Cabinet Folder, and scroll down to the Quaranta. The AW-27 usually is seen in the Waverly cabinet, which is wide enough to accommodate the extra long amp chassis. Supplied with a 15 inch Magnavox instead of 12", - and the tweeter pair. The AW-27 is a rare variant.

FYI - The Quaranta models use the AW-27 receiver, but were further enhanced with multiple additional chassis for the additional preamps and a second amp for a separate low frequency channel. and record cutter sporting as many as 40 or 50 tubes total.

AS for how an restored AW-23 sounds - when you have the opportunity, try a CD player into the phono input. You will be astounded with the clarity and volume available. For an early 5 knob AW-23, your CD player needs its own volume control ... for a later 7 knob, the set volume control functions.

[Jon Ketron]

David,

Thank you the correction.  I appreciate you going into detail on the AW-27.  Very interesting.  I look forward to restoring the AW-23.  Would you happen to have production numbers on the AW-27?  I have a friend out of Cincinnati who once had a Baby Quantra with all the features you mentioned above.  Rough cabinet, chassis was good though.  I never did see it in person.  I think he sold it for $5,000 back in the 90's.  Would imagine they command the same price or higher in today's market.

Jon

[David C. Poland]

Be Bill Sherer?  Kent acquired it years ago.  In a Waverly cabinet.  I recently did a little cabinet work on it for Kent.

Not many produced and no factory diagram located either. Last I knew Kent had under a dozen in his data base.

[Jon Ketron]

Yes David.  Bill is a very good friend of mine.  He has told me the story of the Baby Quantra several times, mainly because I have asked about it in the past.  The history of how he obtained the set is quite interesting.  Is that AW-27 in a Waverly Grand cabinet complete with phonograph?  Wow that is low estimated production numbers.  I am originally out of Cincinnati, having moved to Lexington KY just several years ago.  I still frequent OH quite often and stop in to say hello to Bill from time to time.

Thanks,

Jon

[Norman S Braithwaite]

David C. Poland said:

And there are 2 additional controls flanking the usual controls, one for control of the expander circuit and the other for the BFO instead of the button under the the band switch. The AW-27 escutcheon set is usually bright gold rather than darker bronze color.

The AW-27 does not have a BFO. The BFO tube was removed to accommodate the volume range expander. The controls below the tuning knob are as follows: Radio/Phono, Volume, Bass, Expander, Selectivity/Hi Fidelity, and Sensitivity. Gold plated escutcheons were not used on all AW-27 sets and, like the AW-23, tweeters were optional. At least one very deluxe original AW-27 has turned up without tweeters. I haven't been counting but I believe the reported serial number count for the AW-27 is up to about 15.

Norman