I am restoring a model 42-285 code 121 console for a friend. He pays for parts and I get to enjoy my hobby. Well, the cabinet label shows a 9 tube chassis tube diagram. When the chassis was removed the first hint all was not well was that the chassis had a 3/16th add-on shim under it so as to raise it enough that the dial seated properly. The next issue was that the chassis was a 7 tube unit. Has the same push button and osc tuning coils/capacitors as the 42-285 but while the 42-285 has a three wafer band switch the installed chassis has a one wafer switch. So, my question is what chassis is it? Stamped in the metal is M30235 and stamped in ink is 11167. I suspect the M30235 is the chassis ID.?????? I had restored a 42-285 for my sister which had the 9 tube chassis and retained the schematic and alignment instructions. I found that documentation on Nostalgia Air but they have no data base for a chasssis number search. So, I am asking for advice on obtaining documentation for the 7 tube chassis. I suspect the 7 tube chassis was originally installed in a table top cabinet. Richard
(title edited by admin for clarity)
Hi Richard and welcome,
The $64 question is what loop ant does it have? That will distinguish it from a table top set. It would help if you could post a pic or two of the chassis, fnt, back and top. Can't find anything on a 42-285. There is a 41-285.
Richard
Simply make a picture of the chassis and put it here. Or go into the Philco of the appropriate years' period and see what chassis had how many tubes, and look at the chassis' drawings in the doc files.
Woops, sorry about the model number. It starts with 41-. Attached find some photo's. You will see a switch someone added hanging on some audio cables. On the back is an RCA jack for phone/tv connected to one side of the switch. I intend to remove/relocate the switch.
on the loop is stamped 80 5 790
The chassis looks kind of like a 40-180. I don't think the loop antenna you have will work with that chassis as it is a low impedance loop used with 41 and later models. The 1940 models used a different loop in a cardboard tube enclosure.
Se if this 40-180 service info corresponds to the chassis you have:
https://philcoradio.com/library/download...20Book.pdf
Thanks, Mondail, the 40-180 schematic looks a lot like the chassis in question. I will look at closer. Richard
Mondial is correct - the chassis is a 40-180. The key giveaway is the converter-oscillator tube, which has a grid cap - clearly intended to be a 6J8GT (originally 6J8G).
It looks like someone stuck a 40-180 chassis in a 41-280 cabinet. As Mondial said, that loop antenna will not work with the 40-180 chassis. The 40-180 not only requires a large loop covered in heavy brown paper for AM reception, but also a simple one-turn loop mounted under the top of the cabinet for SW reception.
The converter tube confused me a bit which is why I wasn't completely sure if it was a 40-180. It should be a 6J8G, but I don't think the 6J8 was ever was made in a GT version.
It looks like someone substituted a 6A8GT for the 6J8G. Although totally different in construction, they are pin compatible and might actually work in the 40-180 as a sub. Sylvania mentions their compatibility in an early datasheet:
https://www.tubesandmore.com/sites/defau...s/6j8g.pdf
You are correct.
So someone just shoved a tube in there thinking it would do. If a 6A8GT, yes, it might indeed work.
These 1940 Philcos are interesting animals. First produced with a 7J7 Loktal converter-oscillator, Philco later switched to the 6J8G, then back to the 7J7.
I suppose they ran short of 7J7 tubes during production and switched to 6J8G until they could get 7J7s again?
Yes, I assume they ran short of 7J7's in production and used the equivalent 6J8G to fill in. Or did Philco get a really good deal on a lot of 6J8G tubes?
I always wondered why Philco went back to the already obsolete 6 pin type 41 and 84 tubes, when octal and loctal equivalents were widely available. In the 37 models they switched to all more modern style octals, only to revert back to the older style tubes in later models.
The only thing I can think of is the old style tubes were cheaper and more available in quantity. Still it seems somewhat strange that you would design a radio in the 40's with the latest loctals and pair them up with outputs and rectifiers from the early 30's.
Now that is a good question and I have often wondered the same. As you say, though, the answer was likely cost savings as Philco was already cheapening their products as much as possible.
Whow! You guys know Philco in great depth. Thanks for all the responses. After comparison with the 40-180,40-185,40-190 schematic it seems to be a 40-185 or 40-190 because the on/off switch is on the tone control as depicted on the schematic by dashed lines. Now the search for the proper antenna loop begins. I have an RCA "magic loop" which might be able to do a swap. Richard.
I don't think you have a 40-185 or 40-190 because both of these are 8 tube chassis.
Since you have a 7 tube chassis, it must be a 40-180. All three models have the power switch on the tone control.
This is what the correct loop antenna looks like:
Thanks again, I understand the on/off switch issue. Thanks for the photo of the antenna. Have you ever heard of anyone fabricating a replacement antenna?
It could be done, and has been. Paul Pinyot's website used to give instructions for doing so. Unfortunately, he is no longer with us, and neither is his website.
Part of his site is on the Wayback Machine, and there is a link to the page which once contained instructions for fabricating the 1940 console loop antenna. However, all of the links are now dead, the images gone.
http://web.archive.org/web/2015030608391...ntenna.htm