EH Scott Radio Enthusiasts

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ELECTRICAL RESTORATION: All Wave 12 Deluxe

Hello all,

I have started another E.H. Scott restoration and wanted to share my progress for those interested.  Pictured is an early version AW12 Deluxe with AVC (Wunderlich tube) housed in an early version Tasman cabinet.  Upon receipt of the electronics, the set was wired for use with an 1930's era PM speaker.  The original E.H. Scott speaker was missing.  I purchased the set with a correct and working pair of E.H. Scott Rola twin speakers.  This Rola speaker setup has been seen and documented on early examples of the AW12 Deluxe chassis, which this set appears to be:

Serial number F-78

The All Wave 12 chassis/power supply and Rola speakers were added to this Tasman cabinet upon purchasing.  All is period correct thus showing an proper example as to what a complete set may have looked like brand new upon purchase via the Laboratory in the early 1930's.  Please feel free to comment as the restoration progresses.  I look forward to making this beautiful AW12 operational again!

Jon

 

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Jon - look forward to seeing it with the chrome  cleaned and polished. The test spot cleaning  of chrome looks promising indeed. The speaker cloth is original and so is the "v" shaped speaker baffel.

Be sure to route the cables away from the hot amp tubes. 

Kent King  already has the serial number.

Dave,

Thanks for the comments and advice.  Looking forward to the end result as well.

Jon

All chassis have now been removed from the cabinet.  First up for electrical restoration will be the tuner:

Analysis of the top side:  A cardboard sleeve rests over the electrolytic condenser, signifying this machine was sent back to the Laboratory at some-point in time for repair's.  It is obvious someone had been into the tuner chassis after leaving the E.H. Scott Laboratory the second time as the bottom cover rivets are missing.  Original acorn lug nuts are missing on the tuner bottom cover screws and will need to be replaced.  I plan to clean the tuner chrome with a vacuum cleaner and dry brush first.  Then utilizing a damp cloth, wipe each area with a clean piece of cloth as I remove dust and contaminants.  This method insures the least amount of damage to the chrome (in terms of scratching).  Radio tubes will be cleaned, checked, and set aside for our first power-up down the road.

Analysis of the bottom side:  For the most part all original components are still in their original places upon leaving the Laboratory the first time.  Nothing really looks disturbed.  Three items that look to be replacements or additions are visible: 

The volume control has been replaced

.003 MFD Solar brand wax cap has taken the place of the original bath tub cap that used to reside in such location (if one did)

E.H. Scott likely added the orange 1/4 MFD Potter wax capacitor once this set returned to the Laboratory for repairs.  Perhaps dating the return to the Laboratory for repairs around the mid-late 1930's?

Far left side of underside shows a brown wax cap with only a value stamped on it.  These are the same style used underneath the chrome coil covers on the chassis top side.  This is an original E.H. Scott part likely put in place upon being manufactured or added upon return to the Laboratory for repairs.  I have not traced out this capacitor within the circuit.

Other than these three items the tuner underside appears to still retain it's original forum.

Jon

Full view pictures of the Tuner chassis.

Jon

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Nice really clean set. 

Thank you Scott.  This AW12 is quite clean underneath.  The third early to mid 1930's E.H. Scott I have had such luck with.

With the tuner up on the bench, top side disassembly has started.  I have also started to clean the chrome as seen in the second and third photo.  Cleaning up real nice!  The large chrome covers on top of the chassis house several items.  Original wax capacitors underneath these cans will need to be accessed and replaced with new capacitors.

Jon

Full view pictures of the tuner chassis top side:

Jon

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All top side covers have now been removed, allowing for inspection.  Removing several of the coil covers can be a job.  The grid caps need to be removed from the lead wire.  The lead wire (shielded) has to be de-soldered from the grounding point on the can.  Upon replacing the cover, a long piece of wire needs to be temporarily soldered to the grid lead, pulled through the eyelet on the can, then removed.  All solder points and grid caps and then be restored.  From experience, I have come to realize you have to be quick re-soldering the shielded grid lead to the grounding point on the covers.  If too much heat is applied, tar will start to seep through from the lead wire within.  Doesn't make for nice sight with all that chrome in view.  I have since corrected this issue with less heat applied to the joint and cleaning of the area with rubbing alcohol afterward.

All three capacitors have now been replaced. 

It's amazing to think this is the first time these coils and components have seen the light of day since 1931-1932!

Jon

 

Full resolution photos:

Jon

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Jon,

Thank you for posting your progress, especially the pictures. I am close to embarking on the same journey with my Deluxe. From the pictures, I have already noticed a difference between your early production chassis and mine.  Seems I have an extra electrolytic, which I presume is a design change made during production.  I look forward to the next posting of your progress.

Todd

Todd,

Thank you for your comments.  I hope this topic provides a great resource for your All Wave 12 restoration.  From my own experience working on several E.H. Scott models, I have come to realize no two are identical.  Design changes are interesting to note and important to document.  I look forward to seeing your chassis down the road and perhaps compare design changes.  The AW-12 is a fine set and quite ahead of competition back in the day.

Jon

Everything top side on the tuner has been cleaned, checked, and re-assembled.  A full detail of all tuner chrome took place afterward.  It's amazing what a little bit of elbow grease can do!

Jon

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