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

 

[Jon Ketron]

Thanks Mike.  I will have to check out the AW-15 video you mention.  I found Part 1 and Part 2 on YouTube and will be watching shortly.  I will do as Kent and you suggest.

Jon

 
mike hadley said:

Jon,

For what it's worth, if you watch the video on youtube about making the aw15, you will notice that in one shot the chassis has the one cap and two filter setup like mine, in a later shot there are clearly four bathtub boxes fixed to the rear of the chassis, so this means that they were probably making changes on an almost daily basis,

not an easy thing to deal with eighty years on, use the circuit diagram and a pencil I think is the best method.

Mike

[mike hadley]

Jon

My power supply does have the two bathtubs, I have attached a scan of the circuit, I have checked this several times although the circuit looks a little odd, the switches are normally closed, I have amended the original in red.

Mike

[Jon Ketron]

This is a huge help Mike, thank you for taking the time to do this.  If all works out well I will be back with the amp chassis fully re-capped tonight.

Thanks

Jon

[mike hadley]

Jon;

my allwave is an early one, four posts at the back and a wunderlich detector,

I have been meaning to draw the psu for some time now, as it was the first part I recapped, my transformer died and it now has a new rewind, one of the ht secondaries developed a short.

I would like to take this opportunity to show you the main caps in my psu.

The originals were broken off of the chassis and beyond repair, what you see is three salvaged pcb mount caps upside down with homemade brass mounts for the chassis and sheet metal discs crimped in, the caps contain 8uf motor run caps, neat huh?

Mike

[Joseph W Strickland]

Mike;

Thanks for that picture and explanation. I now have an idea how to replace one missing electrolytic on the power supply of my 800B. Did you machine brass pieces to use in mounting them, or did you find something off-the-shelf that you could adapt to your needs? I currently have a motor run capacitor underneath the chassis but would like to mount one top side like the original. Unfortunately the old cap was leaking and causing corrosion underneath the chassis. When I tried to unscrew it after removing the connections, the insides were just spinning with the turning of the nut and it would not unscrew. I wound up having to break the plastic threads off the bottom of the capacitor assembly to get the old one off the chassis. I am thinking perhaps just use a piece of brass pipe and nuts to fit along with star washer.

Joe

[Jon Ketron]

Mike,

Very nice reproduction, looks very close to the originals.

Jon
 
mike hadley said:

Jon;

my allwave is an early one, four posts at the back and a wunderlich detector,

I have been meaning to draw the psu for some time now, as it was the first part I recapped, my transformer died and it now has a new rewind, one of the ht secondaries developed a short.

I would like to take this opportunity to show you the main caps in my psu.

The originals were broken off of the chassis and beyond repair, what you see is three salvaged pcb mount caps upside down with homemade brass mounts for the chassis and sheet metal discs crimped in, the caps contain 8uf motor run caps, neat huh?

Mike

[Jon Ketron]

All,

I have finished the power supply just a little bit ago.  I used 18 gauge buss wire double looped to secure the negative sides of the electrolytic network and 205K cap.  The buss wire connection makes for a very sturdy mounting surface free from touching the chassis and from moving.  I did not have any terminal strips on hand this time around.  All capacitors were in someway secured using pure silicon.  While not best suited for fit and finish, this will allow the original components to be "re-stuffed" down the road if decided by the owner.  All original bathtub capacitors and electrolytic's have been disconnected for the circuit.  All resistors have been changed out with proper replacements. 

"Simichrome" is an excellent product when it comes to polishing these chrome chassis.

Jon

[mike hadley]

The caps are a result of desperation, the bottom fitting is a cut down cable gland with a long bolt potted in the middle with epoxy, this has bolt has a solder tag and a thick copper wire under the hex end for the cap connection, the new cap is then inserted in the housing with thin cardboard (filing cabinet folders are good) rolled around the new capacitor to take up any excess space between the motor cap and tube, when bolted to the chassis all connections are tight and good. 

when you prepare the donor cap, if you take a file to the bottom of the rolled seal you can file this edge until you see a thin line, its then quite easy to remove the old crimped over end, this will then leave enough 'meat' to roll over a new edge after stuffing

the description of this is more difficult to explain than the process, I will take some photo's and make a post about this at the weekend,

[Joseph W Strickland]

Mike;

I had to look up cable gland before I understood what you meant. To us here in the US it is a cable fitting or cable termination piece normally used with conduit tubing to protect wires where they enter/exit an electrical circuit box or panel. I like the idea - off the shelf parts that can serve the purpose. The bolt(s) coming through along with some epoxy to keep them insulated and positioned correctly combine to create connections just as serviceable as the originals. This is a really neat idea for replacements!

Joe

[Jon Ketron]

Yes Mike, please share your method this weekend.  It would be good to have substitutions on hand if needed.

Jon

[mike hadley]

Jon,

I have just "made" a new cap, no guts just a case, loads of photographs.

I will put together a blog to show how

[Jon Ketron]

Now with the power amp complete, I have moved onto the last part of this electrical restoration.  Everything underneath looks untouched after all these years.  Someone must of been inside this chassis at one point though.  The chassis cover rivets were missing and one screw to the turret cover was missing.  Perhaps an adjustment was needed to be made when the power amp was worked on years ago.  Either way I sure like what I see.  Of all the pre-WWII radio's I have restored and worked on within the last 10 years, this is by far the best built tuner chassis I have ever come across for this vintage.  Quality that cant be beat!

My main question at this point: Any recommendations on taking the turret wheel out of the chassis? I need to access both bathtub caps that reside below this section of the chassis.  I have not touched the turret yet as I know it needs to be taken out a certain way.

Thanks

Jon