EH Scott Radio Enthusiasts

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SCOTT PHILHARMONIC MODEL XXX - Serial No. D-751 = MUST TEAR DOWN TO FRAME TO RE-CHROME CHASSIS

am the proud new owner of a Scott Philharmonic Model XXX, Serial Number D-751 on main chassis. Bought this chassis and its companion power supply (came with NO speaker or cabinet) on eBay from a seller in California (who knows nothing about old radios other than that they're interesting old items worth selling on his eBay site). I opened up the main receiver chassis, which arrived by FedEx today, Saturday, February 17, 2018, and it appears NEVER to have been worked on! NO replacement parts in it whatsoever, nor ANY evidence of work done. The chrome on the main receiver chassis is "ROUGH" at best - well past the "clean it up with chrome polish" stage - so this chassis is going to have to be completely re-chromed, including all the tube shields and coil covers, some of which have quite badly pitted chrome plating, but none are missing or dented.
I am faced with no less a task than to completely disassemble this radio down to the bare frame and START OVER, salvaging and thoroughly cleaning every good part for re-use. After I get the main and power chassis back from my chrome plating shop, I will have to basically reassemble this complex radio from scratch, treating it as I would, a "kit," using of course all new wiring and resistors and capacitors. I will have to meticulously follow Scott's original factory layout and workmanship, so I'll be photographing every section of the underside of this as-of-now UNTOUCHED radio BEFORE I take it apart and then later on, VERY carefully put everything back as closely as possible to as the factory did it. It is the ONLY way I can get at the main and power chassis to free them up to have them re-chromed. IF I can take this radio apart without damaging any of its precious and irreplaceable component parts and reassemble it CORRECTLY, according to the E. H. Scott Radio Laboratories' Schematic, I will be very intrigued to see just how well this radio can be made to work, if it's supplied with all good tubes, and I am able to align it according to Scott's own servicing instructions, which I got together with the complete schematic (for the Model Philharmonic XXX, which is a non-FM, non-Beam of Light set); those arrived on the scene later, around 1939 or 1940 / 1941. I think my radio dates from 1937, if its serial number can be traced to a factory listing.

I will be very much interested to hear from anyone else of you in this E.- H. Scott group who have had to rebuild your set from the ground up, as I am about to do with mine, in order to strip the chassis bare to be re-chromed. It's not enough simply to re-chrome the easily removable parts - I have no choice but to do this to both my power and main radio receiver chassis, to make this radio right again.

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Hi, Jimmie - thank you for your contribution (and empathy with my similar-to-yours state of "speakerlessness")!  

When you "rebuilt" your "Beam of Light" - what exactly did you find you had to do? Did you replace caps and out-of-tolerance resistors, give your radio a thorough cleaning and polishing, and a full set of working tubes - and then align it? Or, did you have to completely disassemble your chassis (in order to have it re-chrome plated) and then put the whole thing back together again with all-new wiring, resistors and caps, and clean and service all the irreplaceable parts?  

When I do mine, I am going to have to do the latter - a full tear-down and rebuild from scratch. Both my Philharmonic chassis (the main receiver one and the one housing the power supply / amplifier) have very ugly rusted chrome which cannot be polished clean.

If you did a full tear-down, how long did it take you to reassemble it once you had your chassis rechromed?
jimmie o. ashabraner said:

having rebuilt a beam of light and not having a speaker I feel for you! the speaker is gonna be a hard thing to find and expensive, so by using an output transformer from a jukebox using 6L6 tubes and a field coil speaker with a tap as the philharmonic used, I managed to use heavy wattage resistors and got the correct split and it works well. Could not wait til a speaker was available to enjoy this radio, jimmie     

I replaced ever cap and bad resistors. went thru dozens of tubes to find ones that worked best, especially ones in the eye tube circuits. don't forget the 1 meg resistors in the tuning eye tube sockets. did an alignment on chassis. overall I probably spent two weeks on it in time. I repaired a Wurlitzer 1015 bubble tube jukebox for the two chassis. man said he threw the speaker in the trash because the cone was torn! have owned 3 allwave 23 scotts, one with tweeters and volume expander which are high priced accessories. good luck on yours. make a lot of notes and pictures as all the changes scott put in his radios are not in riders or scott manuals!!!   regards jimmie     

Just because some part seems to differ from the factory does not mean it is wrong. Check the visuals and if it looks original it may be correct. Scott did make running changes to further performance.

There is a thread a year ago or so on Philharmonic restoration with valuable comments from Norman, mentioning some observations and an obscure circuits  omitted from the factory documentation. 

You may gain some insights by reviewing all the past threads concerning Philharmonic. 

Thank you, Jimmie for answering my questions and your recommendations - I will be paying very careful attention to all the details of my Scott Philharmonic as I take it apart, and I will note any differences (discrepancies) in the wiring that I find in my radio as compared to what is shown on the schematic I have, which I bought from Steven Johnson in Michigan - he has what I think are the best radio schematics available online - his scans of schematics are very high quality - although not everything is fully legible, given the quality of the originals he had on hand to use to scan from.  There are quite a few illegible markings on the Scott Philharmonic XXX Schematic he sold me, so I will have to do my best to decipher them.

Have you been able to find a speaker for your "Beam of Light" Scott Philharmonic? I hope so! You say your set works well - how does it sound, to your ears?



jimmie o. ashabraner said:

I replaced every cap and bad resistor, went thru dozens of tubes to find ones that worked best, especially ones in the eye tube circuits. don't forget the 1 meg resistors in the tuning eye tube sockets, did an alignment on chassis. Overall I probably spent two weeks on it in time. I repaired a Wurlitzer 1015 bubble tube jukebox for the two chassis. Man said he threw the speaker in the trash because the cone was torn! I have owned 3 Allwave 23 Scotts, one with tweeters and volume expander which are high priced accessories. Good luck on yours. Make a lot of notes and pictures as all the changes Scott put in his radios are not in Rider's or Scott's manuals!!!   Regards, jimmie     

probably the best sounding radio besides a zenith shutterdial of 1938 that I have owned and heard play as well. only speaker I have found was way out of my price range at 900 dollars   jimmie

I look forward to seeing pictures of this rebuild. 

As for the tube sockets, I have 3 dial pointer sets and other than the 4 ceramic sockets, they are all riveted and will drop down with the wiring intact. 

The tube covers are aluminum and depending on the level of pitting, they may or may not be rechromable.  People have had good luck with Advanced Plating in Nashville for these covers.  The guy who did my Philharmonic did a great job on the tube shields, but really crapped out on the main chassis- the bottom of it is terrible. 

I wish you luck with the speaker.  Start stalking E-bay now, because they don't come up for sale very often. So many of them have been shipped to Asia. 

Do you have any pictures of the undersides of your McMurdo's on the net?

 I have restored (repaired) over six Philharmonics, both AM/FM and just AM versions and have had problems with half of them with either oscillating IF strips or gross distortion of the 455kHz. in the IF strip or over driving the 2nd detector. I've also restored a dozen Allwave 23 radios and they have a tricky IF alignment issue and have to be sweep aligned if you really want good wideband audio. But the problem with the IF strip in the Philharmonic has to do with the poor AVC action of the tubes used in the Philharmonic, while the Allwave 23 used the 39/44 tubes in part of the IF strip and when the AVC detector says reduce the gain the 39/44 does a better job.

what I did in the Philharmonic was to add 100k resistors in the grid of all IF stages, then realign the IF strip, then sweep align the all IF stage starting with the 2nd detector, moving towards the mixer. this modification does not change the radios sensitivity (I've got measurement data) and it eliminates all of the audio distortion, typically 5% THD down to 1.5%, as measured from the antenna terminals to the volume control high end. measurement tools are a Tektronix SG505 and AA501 feeding a HP 606A, for IF looking using a Tektronix 2465 400MHz oscilloscope. the 100k resistors do two things, they lower the grid current when the IF tubes are over driven and allow the AVC voltage to have wider range of control. and if any of you don't believe that when the 2nd detector is driven hard it doesn't produce audio distortion, just look at the plate with a scope and you will see 455kHz sine waves compressed and distorted at the peaks.

~Richard Majestic

wish I had all your equipment and knowledge. I assume you meant break the grid connection to the tube and insert the 100k resistors. all I have to work with is an eico signal generator and a digital frequency readout meter. Working on the philharmonic was a challenge. Most of the time during daylight hours I run an FM converter thru the phono input as reception is poor on AM. thanks for your input, are you a retired electrical engineer? I am a retired electrician and sign painter who owned my own sign business 30 years. My first radio as a teenager was a Philmore crystal radio and headset which brought in 2 stations on a short antenna.  regards, Jimmie

Richard Majestic was trained at the RCA Institutes, an electronics school. He went on to work for the Brookhaven National Laboratory, Voice of America then ABC/ESPN as a broadcast engineer. Richard also worked as an engineer in the 1970’s for the Bozak loudspeaker company. He owned his own company RAM Audio which designed stereo hi fi equipment for North America Phillips. Richard finished his career working for Sony’s commercial broadcast equipment division.



jimmie o. ashabraner said:

wish I had all your equipment and knowledge. I assume you meant break the grid connection to the tube and insert the 100k resistors. all I have to work with is an eico signal generator and a digital frequency readout meter. Working on the philharmonic was a challenge. Most of the time during daylight hours I run an FM converter thru the phono input as reception is poor on AM. thanks for your input, are you a retired electrical engineer? I am a retired electrician and sign painter who owned my own sign business 30 years. My first radio as a teenager was a Philmore crystal radio and headset which brought in 2 stations on a short antenna.  regards, Jimmie

Hi, Scott Seickel - I appreciate and thank you for your input to this discussion.  I'm glad to know the tube covers are made of aluminum - when I send them to my plating shop in Chicago, I'll have them polished - aluminum must NOT be chrome-plated - although it CAN be done, it's not advisable - so I'll have mine polished. You mentioned that when you had the "bottom" of your main chassis rechromed - what are you referring to - the UNDERSIDE of the main chassis itself where all the wiring and components are mounted? - or are you referring to the removable cover plate which is fastened to the bottom of the chassis and protects its "innards"?  If the latter, I'll just scrub it clean with fine steel wool and mineral spirits and remount it.  When I had my McMurdo-Silver chassis re-chromed, my plating shop plated the UNDERSIDE of my main chassis only with Copper and Nickel, so I could solder grounds to it - NO CHROME!  I did not have them work on the metal bottom cover plates, which appear to be tin-plated steel, because they were just dirty, not rusted, so I could simply scrub them clean.

On my Pointer-Dial Philharmonic, SOME of the tube sockets (besides the four ceramic ones) are held in by rivets, and SOME are inserted from above, as the McMurdo set's are, and held in place with spring clips in the same way. So, I'm faced with a mixed-bag of disassembly challenges.

I am including in my reply here two photos I've taken of the restored undersides of my two McMurdo-Silver sets, one of the Masterpiece V and the other, of my Masterpiece VI, so you can see what I've done.  Also, a third photo of the top-side of my Masterpiece V with its re-chromed chassis and coil covers, etc.

Scott Seickel said:

I look forward to seeing pictures of this rebuild. 

As for the tube sockets, I have 3 dial pointer sets and other than the 4 ceramic sockets, they are all riveted and will drop down with the wiring intact. 

The tube covers are aluminum and depending on the level of pitting, they may or may not be rechromable.  People have had good luck with Advanced Plating in Nashville for these covers.  The guy who did my Philharmonic did a great job on the tube shields, but really crapped out on the main chassis- the bottom of it is terrible. 

I wish you luck with the speaker.  Start stalking E-bay now, because they don't come up for sale very often. So many of them have been shipped to Asia. 

Do you have any pictures of the undersides of your McMurdo's on the net?

Hi Jos.  That is a beautiful job you did on those radios.  Thank you for the pictures. 

That is how I want the bottom of my Philharmonic to look, unfortunately, it came back with copper showing and spots of chrome flash everywhere and it looks like a mess.  While the top looks good, I need to send my chassis out to a more competent plater so the chassis can be redone to look like yours.  The plater said that all the holes in the chassis gave him a hard time with the plating process.   Funny thing is that this plater did an excellent job on the tube shields which by all accounts are harder to do.  What plater are you using?

As for the tube shields, I would definitely have them rechromed.  They were chrome originally and chrome on aluminum is fine.  Polished aluminum will never look correct, plus even if polished, their shine will fade as the aluminum oxidizes.  Chrome is done on aluminum car wheels all the time and it has reasonable durability if done correctly. 

I also sent you a friend request on this forum.  Please accept it so I can send you a private message. 

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