Service Bulletin No. The grid filter resistor for the last 27 and the 47 tubes 51, in Service Bulletin No. Do not substitute either of these condensate, use the part munbers givem.
Model 90 receivers are for operation on to volt, cyclevAC lines. This receiver is a nine tube superheterodyne with push-pull pentode output. Automatic volume control, 4 point tone control, super control screen grid tubes and combination llrst detector and oscillator tube are some of the additional features. Set Tester Rectifier 2, Above readings taken with volume control at maximum And dial turned to low frequnecy end.
Electrolytic 0. Electrolytic Table 4-Resistor Data 1. B, to B, and Above B, For additional Fixed condenser new. Antenna Transformer.
V, Condenser Mmf. All readings taken with antenna disconnected and ground on.
Volume Control nu lull. Qhecker is specially equipped or testing pendodo tubes. Plezee of 80 'nine Yellow u i 2 2 9? Set up the Receiver for operation using standard tubes. Set the Normal-Maximum switch in the Normal position. Intermediate Frequency Adjustment-Re- move the tube shield. Remove the control grid clip of the iirst detector tube Type 24 tube nearest back of the Receiver Chassis under the tube shield.
The "G" terminal must be connected to the Receiver Chassis. The middle switch much be turned to the intermediate position.
The tuning control of the oscillator mga problema sa lipunan at solusyon be set for exactly KC.
Turn the volume control of the Receiver on full. Set the atenuator control so that an audible signal is received in the speaker.The radio had seen a moderate amount of servicing in the past.
Six wax-paper capacitors had been installed to replace likely leaky or open Philco bakelite block capacitors. The copper Mershon filter capacitors had also been replaced. But it appeared, at least initially, that all repairs were reversible.
That being the case, I decided to try to maintain the original top and bottom chassis appearance and to reverse any previous repairs to the extent possible.
The schematic for the Philco 90 can be found on Nostalgia Air. Any part numbers will refer to numbers on that schematic. The schematic at Philcoradio. My antique radio restoration logs.
Philco Diagrams, Schematics, Service Manuals
This radio was purchased on eBay at a reasonable price these models go for big bucks, especially if refinished or have excellent original finish cabinets. My example cabinet was presentable, with no damage or serious scratches or dings, but the finish was heavily oxidized, and very dark.
It had its original knobs and grille cloth, and the cloth was in good condition. The power cord was original, but frayed in places.
All tube shields were in place. When the radio was removed from the cabinet, it appeared that mice had been living inside! There were lots of seeds and some nuts present. But I saw no evidence of component damage or excessive corrosion due to their urine.
After cabinet cleaning, I did discover where small nails had been used to secure the arch brace and the cabinet base. These were hardly visible and were left in place, since attempting to remove them would likely result in more damage to the finish.
The eBay seller did an excellent job at packing triple boxed! Here is what the radio looked like as received:. The radio had seen a moderate amount of repair in the past, and all repairs were far in the past, judging from the components used. This was a well loved radio that someone paid a lot to have repaired, and several times.
Six wax-paper capacitors had been installed to replace the usually leaky Philco bakelite block capacitors. In three cases, the replacement capacitors had been installed in parallel with the existing capacitors, which had not been disconnected perhaps they had failed open? In the other three cases, wiring and other components had been disconnected from the bakelite blocks and left hanging in space.
In one case, one of the lugs of a bakelite block capacitor had been cut short. But NONE of the original bakelite blocks had been removed, fortunately.
Once restoration started, and the bakelite block capacitors were removed for restuffing, I found that in cases a terminal had been cut and then soldered back to the stub left on the capacitor!
This was not obvious until the solder on the terminal was melted in order to remove a component or wire. The two copper Mershon filter capacitors had been removed and replaced by tubular capacitors under the chassis.
There were signs of leakage and corrosion on top of the chassis where the originals had been mounted. The metal cased bypass capacitor blocks were all still in place.The Philco model 90 Baby Grand, introduced in June ofcontinued the line of successful Philco compacts that had begun with the model 20 Baby Grand almost a year earlier, in August of Its robust, no-nonsense but classical demeanor has made it today one of the most famous and widely recognizable of all vintage radios.
The cabinet design, patented in February of by Edward L. Combswas shared with several other Baby Grands, including the models 21 and However, the 90's cabinet is the largest of them all and is immediately distinguishable because of the vaulted mouldings around its base, compared with continuous mouldings on each of the other models.
There was an evolution of the 90's chassis through its year of manufacture June to June At the time of its intro- duction the circuit used push-pull 45s in the output stage and provided no AVC. This required an extra tube and so the push- pull output stage was reconfigured to be single-ended, using one of the new type 47 power pentode tubes, in order to keep the tube count at 9. At the same time, operation of the AVC was improved by adopting the latest type 35 variable mu tubes.
Of these three Baby Grand variants, the second is by far the most commonly found today. The first version turns up from time-to-time, though the third version, with dual 47s, seems particularly rare. I have both first and second versions of the model 90 the set photographed is the first.
Philco Radio & Television Corp. 90-A Schematic
The radio covers the standard broadcast band from kc and uses a 4-point tone cont- rol "brilliant", "bright", "mellow" "deep". The schematics may be found here for all versions, courtesy of NostalgiaAir. Philco Copyright TubeRadioLand.
Pentode Extra Power Tube Extra Large Size Dynamic Speaker Full-Range Tone Control Lighted Dial. A Super-Powerful Baby Grand with a pleasing tone.The Philco Model 90 is the most desired cathedral radio of all time in the eyes of many collectors. Designed by Edward Combs, its classic lines epitomize the cathedral style, which became wildly popular in the s. Inthe year before the Model 90's introduction, Philco had scored a home run with its "midget" Model 20, a tabletop radio with a rounded cathedral cabinet, offering the same performance as much larger console radios in a smaller, cheaper package.
Prior to that time, most radios came in one of two packages. Console, or floor-standing models, came in squarish sometimes ornate wooden cabinets, usually standing on thin wooden legs.
Tabletop models generally came in plain, coffin-shaped boxes. The new "midget" cabinet was much smaller than contemporary consoles, yet more attractive than the coffin style tabletops of the s.
Philco sales skyrocketed, quickly launching the company to the top of the US radio market. Philco was not the first manufacturer to offer a cathedral cabinet, however. That honor belongs to Jackson Bell for their cathedrals, and possibly one or two other minor manufacturers. The Philco Model 90 capitalized on the success of Model 20 and added some key innovations.
First, it adopted the newer superheterodyne electronic design, which offered better performance than the finicky TRF tuned regenerative frequency design and was ultimately embraced by all radio manufacturers. The 90 also added a tone control, which is the leftmost knob as you look at the front.
Click it to the left for more treble, and to the right for more bass. Model 90 employed nine tubes compared to the seven of Model The tube lineup is as follows: 80, 24, 27, 24, 24, 24, 27, 45, The Model 90 cabinet is more sophisticated and dressy than that of the Model 20, which has the same general size and shape, with a fancy grille, but an otherwise plain-Jane front panel.
The Model 90 cabinet adds stately columns at the sides of the cabinet, creating a distinctive "Gothic arch" appearance. It also adds discrete feet at the bottom corners, along with more complicated beveling and pattern-matched veneer in the upper front perimeter. Judging by continued interest over the decades, this has to rank as one of the most successful and pleasing of all cathedral radio designs.
Despite the "midget" appellation, this is a large, heavy tabletop by modern standards. It's a midget only in comparison to a full-sized console radio. If you ship one of these sets, I advise removing both the chassis and the speaker and packing them in separate boxes. If they are left in place and the box is dropped, the heavy chassis may crash right through the bottom of the cabinet. Even worse things might happen if the radio happened to fall on its face.
All Philco 90s have the same cabinet, but there are two different electronic versions.
Philco 90B Cathedral Restoration
Mine is the early one, which used two type 45 tubes in a "push-pull" circuit to provide high-quality and loud! Put simply, AVC smooths out the signal strength between very strong local broadcast stations and faint, distant stations. If you are listening to a radio without AVC, the difference is obvious as you turn the tuner. If you turn up the volume far enough to receive a faint distant station, the radio will blast your ears off when you tune into a strong local station.
The second version of Model 90, introduced in October,used a single type 47 tube for audio output and it did have AVC, making "station surfing" a less ear-shattering experience. The toggle switch is visible in the following photo, near the center of the chassis back.
If you plan to change from a strong local station to a faint, distant station, you would flip the switch from Local to Distant. This turns up the gain on the receiver for the faint station, an operation that is done automatically with AVC.
If you find a radio with this cabinet, look carefully at the details. More than one Philco model was offered in this cabinet, and there is even a modern transistorized reproduction that although smaller bears a strong resemblance. During the same years as the Model 90, Philco also sold the Model 70, a cathedral with the same cabinet but only seven tubes and somewhat lesser performance.
The 70 outsold the 90 by a factor of more than two to one, so if you want a vintage cathedral that looks like this but you don't care so much about its performance, a 70 is a fine choice.Models 90 and 90A were available in a cathedral, a lowboy, and a highboy cabinet.
The chassis was made in three versions - an early model 90 and 90A with two 45 output tubes in push-pull, a middle version with one 47 output tube, and a late version with two 47 output tubes. The models 90 and 90A "early" and "middle" have a 4-gang tuning condenser plus 3 tuned IF circuit - both with IF Rider's change note The version "middle"which are above serial numberof the model 90 and 90A has tubes: 24 RF, 27 osc, 24 1st det.
The "late" model 90 and 90A again have push-pull output but with 2 x 47 tubes. Applied on models serial B to B and above B They have a 3-gang tuning condenser and only 6 tuned circuits.
The same differences can be found for all cabinets, both 90 and 90A: Baby Grand CathedralLowboy and Highboy with a stretcher. The cathedral cabinet is the classic design by Edward L. Coombs, and is similar to the cathedral versions of model 21, 35, 46, and All listed radios etc. Google Translate:. Use red slider bar for more.
Select picture or schematic to display from thumbnails on the right and click for download. Collection of Udo Wanninger CH. Collection of Guglielmo Rebuffo I. Philco, Philadelphia Stg. Year: Electro Magnetic Dynamic LS moving-coil with field excitation coil.Philco 90 Radio - Operating
Table-Cathedral-Type upright, round top or gothic arch, not rounded edges only. Philco Radio Philco 90 Cathedral? Posted: Mar Mon 10, pm. Hi all, Does anyone know if a Philco 90 chassis will fit in the any of the similiar cathedral cabinets, such as the model 70 or model 20? I have a very nice restorable model 90 chassis here that I would like to find a cabinet for.
I am assuming that finding a model 90 cathedral cabinet is going to be very difficult? Regards, Ed. There is someone who makes unfinished reproduction 90 cabinets and individual replacement parts - a friend of mine bought one and it is decent but needs an experienced hand in putting a finish on it.
I'll check and see if I can come up with the name - or perhaps someone on here knows who this is Edit - I found it on the Philcoradio. Ed, Here is a picture of the unfinished cabinet purchased from Dick Oliver. He does a very good job reproducing it. It will just take lots of toner and stain to get it the right tone and color you want. The green tone is probably all the fluorescent lights in my shop.
The dark wood is walnut. The other wood is actually white maybe poplar. I stained it and then used toner to get it the color I needed. It was for a friend of mine and I do not have any after pictures of the radio. The cabinet is very well built. Scott, That cabinet looks quite nice. I will have to give Dick a call. I will also keep my eye open for an unrestored Model Maybe between two of them I can put one together.
Posted: Mar Tue 11, am. A well done reproduction is a mixed blessing - at some point they'll sell with no mention of the case being new.Philco Model 90 Lowboy Console It sold almost as well in its day as did that other contemp- orary Philco offering, the model 90 Baby Grandwhich has gone on to become a veritable icon in the vintage radio community today.
Both models utilized the same 9-tube Philco Balanced Superheterodyne chassis type, which at first appeared without automatic-volume-control AVC and with push- pull 45s in its output circuit. The text of a June Philco newspaper advertisement featuring this version of the lowboy is reproduced in the box below.
By late September ofall versions of the 90 were being promoted as having AVC and as using a new pentode power tube the type 47as seen in the advertisement below right.
Free Philco Cathedral/Grandfather Clock Radio Schematic & Owners/Service Manual
NEW in Design. NEW in Principle. NEW in Performance! Balanced Units Four-point tone control This magnificent lowboy cabinet comes in American black walnut and figured butt walnut with arch of V-matched Oriental wood.
Decoration in pin-stripe walnut and quilted maple. Hand-rubbed lacquer finish. Two power-tubes - push-pull. Long-distance switch. Oversize electro-dynamic speaker. Illuminated station recording dial. Complete with 9 tubes". Marvelous distance and wonderful tone!
Back in the summer ofwhen the model 20 was introduced, Philco priced their sets without tubes. That they did so at the time was not a sales ploy, as some might suspect, but was because the tubes were then considered insufficiently robust to be shipped from the factory mounted in the radio.
However, by late Philco was claiming that their tubes were " so rugged that they could be shipped mounted in the receiver sockets ". Thus ended their practice of pric- ing sets minus the tubes and from thence forward they priced and sold their radios "complete with Philco balanced tubes". Note that the lowboy console uses a larger type H2 loudspeaker than that used in the Baby Grand type K2.
Text extracted from a June newspaper ad. Clipped from an early newspaper ad. Copyright TubeRadioLand.