I am looking for information on a Pathe Cathedral Radio. No model number or Serial number. Unit is in marginal working condition at this point. Need ANY information about this radio. I have seen the previous topic in this forum (2001) but thought I would start a new thread to increase visibility.
Here is what I DO know:
*this is an AM broadcast receiver only, no SW or other bands.
*dial is graduated from 0-100
*tube lineup: 80 56 47 47 24 35 35 58
*LARGE 4 gang tuner
*The tuning section appears to be comprised of the 24 35 35 58 - all of which are shielded.
*The top caps from the above all go into IF or RF coil housings.
*These housings are stamped with a 2-letter logo/monogram "AW" in a circle, where the capital 'A' is on top of / over the capital 'W' (Anyone know what manufacturer this represents??)
*Speaker is a "Rola series F-6" which connects to the chassis at the rear by way od a round 5-pin plug.
A label on the rear of the speaker indicates that the impedance is 1800 ohms. This speaker uses a metal cetner spring type diaphram as found in older units (like atwater kent 246).
*chassis is painted blue
*rear of chassis also features 2 dual-banana female receptacles which are labeled as follows:
PHONO HOME BROADCAST and TELEVISION EXTRA SPEAKER
(I don't think these jacks are a kludge. I believe that they are original to the chassis. So much for dating this as a pre-war unit...)
* There are 4 control knobs on the front:
1 = tuner
1 = on-off/volume
1 = tone
1 = local-dx / bandwidth ??
(Of course, none of the controls are labeled).
*also on the rear chassis are 2 screw terminals, 1 for antenna, 1 for ground.
*chasiss dimensions are: 13" wide, 10.5" deep
*cabinet dimensions are: 18" tall, 15" wide, 12" deep
Additional Notes:
The wood cathedral case is large and ornate, with lots of small wood inlay work.
someone recently appears to have started to replace some of the capacitors (the paper ones only, and at that only some of them were replaced) leaving all of the original electrolytic caps under the chassis untouched. There are 2 large sprague can electrolytic caps on the top of the chassis. They might be replacements. I am unsure.
Several resistors down below looked like they have seen a lot of heat.
The unit actually plays (!) with marginal performance (for about 5 minutes before one of the lytic caps below went into failure. Then I shut it down.)
Gain was only adequate with a full long-wire antenna.
Sound output lacked much in the way of bass.
I suspect that may have a lot to do with:
1.) the design of the speaker
2.) electronic components at or near failure.
3.) replaced electronic components of incorrect values from guesswork repairs (lack of schematic)
I know that Pathe went into receivership sometime in the 1920's and that someone bought them out and brough them back. My 'THEORY'is that they had a lot of leftover older components from the 20's production runs and made this radio in the early-mid 40's using some of those components (4 gang tuner from old TRF designs, older tube numbers,0-100 dial scale, old Rola speaker) with some features for 'modern' day use (ie: TELEVISION EXTRA SPEAKER)
whew that wa sa lot of typing.
I hope someone actually reads this.
If you know ANYTHING about this radio or the Pathe company (or maybe YOU actually were THE previous owner of THIS EXACT radio?) do get in touch.
Thanks lots!
Ted B.
TCBname@aol.com
I don't know the details about this specific radio, but I have worked on similar models. First, I would say your radio is from about 1930 to 1933. (Forget about the word "television." Philco was officially the Philco Radio and Television Corporation from the late 1920s. Even back then, TV was the next big thing.) Type 47, 24 (24A) and 35/51 tubes were very common in this time period, then virtually disappeared in 1934.
Here is my guess at which tubes do what.
80 - rectifier
47s - audio outputs
56 - AF driver
24 - biased detector
35s and 58 - RF amps
As for the 56 and 58, they sound out of place with the other tubes. The 56 and 58 were two of the tubes that superceded the tubes used in the very early 1930s. It's possible that, since they were easier to find after World War 2, some past repairman used a 58 to replace an RF amp. (The tube socket would also have been replaced. You should compare this socket with the others in the radio to see if it's different. Many tube sockets had the intended tube types stamped on them, so you might find that different tubes were intended for this radio. For instance, I'd bet that the 56 was probably used to replace a 27. It's also possible that the 58 and the 35s were originally meant to be 24s.)
If that switch is a local-DX switch, it would indicate that 24s or 24As are probably the proper tubes for the RF circuit. (If this switch connects to the RF amp or antenna circuits, then it is a local-DX switch. If it connects to the auxiliary input jacks, then it isn't.)
After you replace the electrolytics, here are some things to check.
The voltage from ground to the control grids (pin 3) of the 47s should be about -16.5 volts. The screens and plates should be about 250 volts. For the RF amps, the voltage between the control grid (top cap) and cathode (pin 4) should be -3 volts. The volume control may adjust this voltage, so you may need to set the volume at maximum before measuring. (See below)
The voltages of the plates of the detector and AF driver should be between 50 and 100 volts, depending on the circuit. The screen (pin 3) of the detector should be about 30 to 50 percent of the plate voltage.
The plates (pin 2) of the RF amps should be between 150 and 250 volts. The screens (pin 3) should be about 30 to 50 percent of whatever the plate voltage is. The volume control may control the screens, so you may need to set the volume control at maximum before measuring. (See below.)
Biased detectors have a resistor and capacitor connected in parallel from the cathode to ground. The two most common combinations for type 24 tubes are 40k resistor/.5 mfd cap and 25k resistor/.25 mfd cap. If one or both have substantially changed in value, shorted or opened, this would cause your poor audio.
The four most common volume control circuits for this vintage of radio are as follows. 1) Screen grid control, mentioned above; 2) Antenna attenuator, where the volume control is connected to the antenna input and/or the input coil; 3) RF amp cathode control, where the volume control is connected between the cathode(s) of one, two, or all three RF amps and ground; 4) some combination of the above three. The volume control may also be connected to the AF driver, but this is rare. Before taking any measurements on this radio, disconnect the top cap of the detector and set the volume at maximum.
Since you got sound from the radio, it's safe to assume the coils and transformers are all OK.
When you replace the electrolytics, don't forget that the one connecting to the negative bias circuit (feeding the -16.5 volts to the 47s) is connected with the positive lead to ground. This is true of any electrolytic connected to control grids. All the others are negative ground. I doubt that any of the electrolytics have a value of more than 10 mfd. Some may be as low as 1 mfd.
Finally, you may need to align the radio. Tune in the highest frequency station the radio can receive. This is usually 0 on a log dial. Adjust the trimmers starting with the one connected to the detector, then adjust each one in order until you reach the one connected to the antenna coil. Retune the radio for the next highest frequency and repeat. 0 should be 1500 kHz, but you can align it to receive up to about 1550 if you want.
Hope this helps.
:Hi there.
:
:I am looking for information on a Pathe Cathedral Radio. No model number or Serial number. Unit is in marginal working condition at this point. Need ANY information about this radio. I have seen the previous topic in this forum (2001) but thought I would start a new thread to increase visibility.
:
:Here is what I DO know:
:
:*this is an AM broadcast receiver only, no SW or other bands.
:
:*dial is graduated from 0-100
:
:*tube lineup: 80 56 47 47 24 35 35 58
:
:*LARGE 4 gang tuner
:
:*The tuning section appears to be comprised of the 24 35 35 58 - all of which are shielded.
:
:*The top caps from the above all go into IF or RF coil housings.
:
:*These housings are stamped with a 2-letter logo/monogram "AW" in a circle, where the capital 'A' is on top of / over the capital 'W' (Anyone know what manufacturer this represents??)
:
:*Speaker is a "Rola series F-6" which connects to the chassis at the rear by way od a round 5-pin plug.
:A label on the rear of the speaker indicates that the impedance is 1800 ohms. This speaker uses a metal cetner spring type diaphram as found in older units (like atwater kent 246).
:
:*chassis is painted blue
:
:*rear of chassis also features 2 dual-banana female receptacles which are labeled as follows:
:PHONO HOME BROADCAST and TELEVISION EXTRA SPEAKER
:(I don't think these jacks are a kludge. I believe that they are original to the chassis. So much for dating this as a pre-war unit...)
:
:* There are 4 control knobs on the front:
:1 = tuner
:1 = on-off/volume
:1 = tone
:1 = local-dx / bandwidth ??
:(Of course, none of the controls are labeled).
:
:*also on the rear chassis are 2 screw terminals, 1 for antenna, 1 for ground.
:
:*chasiss dimensions are: 13" wide, 10.5" deep
:
:*cabinet dimensions are: 18" tall, 15" wide, 12" deep
:
:Additional Notes:
:
:The wood cathedral case is large and ornate, with lots of small wood inlay work.
:
:someone recently appears to have started to replace some of the capacitors (the paper ones only, and at that only some of them were replaced) leaving all of the original electrolytic caps under the chassis untouched. There are 2 large sprague can electrolytic caps on the top of the chassis. They might be replacements. I am unsure.
:
:Several resistors down below looked like they have seen a lot of heat.
:
:The unit actually plays (!) with marginal performance (for about 5 minutes before one of the lytic caps below went into failure. Then I shut it down.)
:
:Gain was only adequate with a full long-wire antenna.
:
:Sound output lacked much in the way of bass.
:I suspect that may have a lot to do with:
:1.) the design of the speaker
:2.) electronic components at or near failure.
:3.) replaced electronic components of incorrect values from guesswork repairs (lack of schematic)
:
:I know that Pathe went into receivership sometime in the 1920's and that someone bought them out and brough them back. My 'THEORY'is that they had a lot of leftover older components from the 20's production runs and made this radio in the early-mid 40's using some of those components (4 gang tuner from old TRF designs, older tube numbers,0-100 dial scale, old Rola speaker) with some features for 'modern' day use (ie: TELEVISION EXTRA SPEAKER)
:
:whew that wa sa lot of typing.
:
:I hope someone actually reads this.
:
:If you know ANYTHING about this radio or the Pathe company (or maybe YOU actually were THE previous owner of THIS EXACT radio?) do get in touch.
:Thanks lots!
:
:Ted B.
:TCBname@aol.com