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11/15/2004 2:15:29 PMgreg
Hello -- need some assistance if anyone can help. Have a Canadian General Electric Model E81 radio and am looking for a power transformer. New to this so I need help as to where to get started on rebuilding this unit. If you can point me in the right direction it would be much appreciated. Tks
11/16/2004 1:31:15 PMThomas Dermody
http://www.nostalgiaair.org/PagesByModel/970/M0028970.pdf

This is the info you need for voltages, schematic, etc. It's listed under Canadian General Electric in the Resources section of this web site.

Voltages are listed. If you can, print a copy on regular typewriter paper, but also print an enlarged copy. Sometimes you can get the diagrams to print out on 8 or 10 pieces of paper. Then you trim and glue the papers together to make a really big and easy to read diagram.

To determine the current requirements of the new power transformer, determine the filament current requirements of each tube. Consult a tube manual for this. You will need a 5 volt filament winding for the 5Y4, and a 6.3 volt filament winding for all the other tubes and pilot lights. The 5 volt filament winding's current rating can be determined simply by the current drawn by the 5Y4 tube. You must add up all the other currents for the other tubes for the 6.3 volt winding. To determine how much current is drawn by the high voltage winding, do the following: FOR EACH TUBE SEPARATELY, multiply its filament current rating by its filament voltage rating. This will give you the WATTAGE drawn by each tube filament. Add these wattages up. Subtract this number from the TOTAL RADIO WATTAGE listed on the label on the back of the set. The number you come up with will be the remaining wattage drawn by all of the tubes' plates and screen grids (the current delivered by the high voltage winding of the transformer). Take this number and divide it by the voltage found on the cathode of the 5Y4 tube. This will give you the AMPERAGE drawn by all the tubes' screen grids and plates. Multiply this number by 1,000 to get the M.A. rating you need for your transformer. The voltage rating of each half of the high voltage winding will be listed on the plate pins of the 5Y4 tube in the circuit diagram. (315 volts--630 volts total divided by two) Since your radio has 315 volts listed, you may purchase a transformer with a 630 volt center tapped HV coil, or if one cannot be found, a 650 will probably do well. This will give you 325 volts per side, which is acceptable.

www.tubesandmore.com is a good source for transformers and other radio components. They also have catologues that can be mailed to you. They go by the name of Antique Electronics Supply.

Thomas

:Hello -- need some assistance if anyone can help. Have a Canadian General Electric Model E81 radio and am looking for a power transformer. New to this so I need help as to where to get started on rebuilding this unit. If you can point me in the right direction it would be much appreciated. Tks

11/22/2004 2:27:32 PMGreg
:http://www.nostalgiaair.org/PagesByModel/970/M0028970.pdf
:
:This is the info you need for voltages, schematic, etc. It's listed under Canadian General Electric in the Resources section of this web site.
:
:Voltages are listed. If you can, print a copy on regular typewriter paper, but also print an enlarged copy. Sometimes you can get the diagrams to print out on 8 or 10 pieces of paper. Then you trim and glue the papers together to make a really big and easy to read diagram.
:
:To determine the current requirements of the new power transformer, determine the filament current requirements of each tube. Consult a tube manual for this. You will need a 5 volt filament winding for the 5Y4, and a 6.3 volt filament winding for all the other tubes and pilot lights. The 5 volt filament winding's current rating can be determined simply by the current drawn by the 5Y4 tube. You must add up all the other currents for the other tubes for the 6.3 volt winding. To determine how much current is drawn by the high voltage winding, do the following: FOR EACH TUBE SEPARATELY, multiply its filament current rating by its filament voltage rating. This will give you the WATTAGE drawn by each tube filament. Add these wattages up. Subtract this number from the TOTAL RADIO WATTAGE listed on the label on the back of the set. The number you come up with will be the remaining wattage drawn by all of the tubes' plates and screen grids (the current delivered by the high voltage winding of the transformer). Take this number and divide it by the voltage found on the cathode of the 5Y4 tube. This will give you the AMPERAGE drawn by all the tubes' screen grids and plates. Multiply this number by 1,000 to get the M.A. rating you need for your transformer. The voltage rating of each half of the high voltage winding will be listed on the plate pins of the 5Y4 tube in the circuit diagram. (315 volts--630 volts total divided by two) Since your radio has 315 volts listed, you may purchase a transformer with a 630 volt center tapped HV coil, or if one cannot be found, a 650 will probably do well. This will give you 325 volts per side, which is acceptable.
:
:www.tubesandmore.com is a good source for transformers and other radio components. They also have catologues that can be mailed to you. They go by the name of Antique Electronics Supply.
:
:Thomas
:
::Hello -- need some assistance if anyone can help. Have a Canadian General Electric Model E81 radio and am looking for a power transformer. New to this so I need help as to where to get started on rebuilding this unit. If you can point me in the right direction it would be much appreciated. Tks
11/22/2004 2:29:06 PMGreg

Thomas, thanks for the info. I posted another message dated 11/22/04 with additional info I gathered since my first message. I'll check out the tubesandmore.com site to see if they can help. Tks again

:http://www.nostalgiaair.org/PagesByModel/970/M0028970.pdf
:
:This is the info you need for voltages, schematic, etc. It's listed under Canadian General Electric in the Resources section of this web site.
:
:Voltages are listed. If you can, print a copy on regular typewriter paper, but also print an enlarged copy. Sometimes you can get the diagrams to print out on 8 or 10 pieces of paper. Then you trim and glue the papers together to make a really big and easy to read diagram.
:
:To determine the current requirements of the new power transformer, determine the filament current requirements of each tube. Consult a tube manual for this. You will need a 5 volt filament winding for the 5Y4, and a 6.3 volt filament winding for all the other tubes and pilot lights. The 5 volt filament winding's current rating can be determined simply by the current drawn by the 5Y4 tube. You must add up all the other currents for the other tubes for the 6.3 volt winding. To determine how much current is drawn by the high voltage winding, do the following: FOR EACH TUBE SEPARATELY, multiply its filament current rating by its filament voltage rating. This will give you the WATTAGE drawn by each tube filament. Add these wattages up. Subtract this number from the TOTAL RADIO WATTAGE listed on the label on the back of the set. The number you come up with will be the remaining wattage drawn by all of the tubes' plates and screen grids (the current delivered by the high voltage winding of the transformer). Take this number and divide it by the voltage found on the cathode of the 5Y4 tube. This will give you the AMPERAGE drawn by all the tubes' screen grids and plates. Multiply this number by 1,000 to get the M.A. rating you need for your transformer. The voltage rating of each half of the high voltage winding will be listed on the plate pins of the 5Y4 tube in the circuit diagram. (315 volts--630 volts total divided by two) Since your radio has 315 volts listed, you may purchase a transformer with a 630 volt center tapped HV coil, or if one cannot be found, a 650 will probably do well. This will give you 325 volts per side, which is acceptable.
:
:www.tubesandmore.com is a good source for transformers and other radio components. They also have catologues that can be mailed to you. They go by the name of Antique Electronics Supply.
:
:Thomas
:
::Hello -- need some assistance if anyone can help. Have a Canadian General Electric Model E81 radio and am looking for a power transformer. New to this so I need help as to where to get started on rebuilding this unit. If you can point me in the right direction it would be much appreciated. Tks

11/22/2004 5:57:04 PMThomas Dermody
No problem. All you have to do is search the power transformer section of their site, or order their catologue. They WILL have an appropriate transformer for you. This will be a lot easier than trying to search for an original. Furthermore, you can be guaranteed that the transformer will be in new condition, and will operate properly. Make sure that the physical dimentions and mounting method used in your radio can be had with the new replacement transformer. If you cannot find a transformer with the proper mounting dimentions and that mounts the way you like (horizontally, vertically, etc.), sometimes you can modify the transformer, or perhaps drill different holes in the chassis. If the new transformer will fit on the chassis, regardless of its position, and also allow all of the lead wires to go safely into the chassis without being exposed, etc., chances are, even if they don't have an exact replacement, you can make something else do. They do have a large line of transformers, though, including some that may not even be listed in their catologue, so you will likely find something that works for you.

T.

:
:Thomas, thanks for the info. I posted another message dated 11/22/04 with additional info I gathered since my first message. I'll check out the tubesandmore.com site to see if they can help. Tks again
:
:
:
:
:
::http://www.nostalgiaair.org/PagesByModel/970/M0028970.pdf
::
::This is the info you need for voltages, schematic, etc. It's listed under Canadian General Electric in the Resources section of this web site.
::
::Voltages are listed. If you can, print a copy on regular typewriter paper, but also print an enlarged copy. Sometimes you can get the diagrams to print out on 8 or 10 pieces of paper. Then you trim and glue the papers together to make a really big and easy to read diagram.
::
::To determine the current requirements of the new power transformer, determine the filament current requirements of each tube. Consult a tube manual for this. You will need a 5 volt filament winding for the 5Y4, and a 6.3 volt filament winding for all the other tubes and pilot lights. The 5 volt filament winding's current rating can be determined simply by the current drawn by the 5Y4 tube. You must add up all the other currents for the other tubes for the 6.3 volt winding. To determine how much current is drawn by the high voltage winding, do the following: FOR EACH TUBE SEPARATELY, multiply its filament current rating by its filament voltage rating. This will give you the WATTAGE drawn by each tube filament. Add these wattages up. Subtract this number from the TOTAL RADIO WATTAGE listed on the label on the back of the set. The number you come up with will be the remaining wattage drawn by all of the tubes' plates and screen grids (the current delivered by the high voltage winding of the transformer). Take this number and divide it by the voltage found on the cathode of the 5Y4 tube. This will give you the AMPERAGE drawn by all the tubes' screen grids and plates. Multiply this number by 1,000 to get the M.A. rating you need for your transformer. The voltage rating of each half of the high voltage winding will be listed on the plate pins of the 5Y4 tube in the circuit diagram. (315 volts--630 volts total divided by two) Since your radio has 315 volts listed, you may purchase a transformer with a 630 volt center tapped HV coil, or if one cannot be found, a 650 will probably do well. This will give you 325 volts per side, which is acceptable.
::
::www.tubesandmore.com is a good source for transformers and other radio components. They also have catologues that can be mailed to you. They go by the name of Antique Electronics Supply.
::
::Thomas
::
:::Hello -- need some assistance if anyone can help. Have a Canadian General Electric Model E81 radio and am looking for a power transformer. New to this so I need help as to where to get started on rebuilding this unit. If you can point me in the right direction it would be much appreciated. Tks

11/23/2004 8:30:41 AMGreg
Thomas, I checked the tubesandmore site and wasn;t sure what transformer would be the correct choice. I then sent an email to tubesandmore asking if they could recommend a transformer to meet my needs -- they just responded saying they have no technical support and could not recommend a selection. Would it be possible for you to review the selection they list on their site and tell me if you see anything that would be appropriate? Once again the info I have from the Operators Manual is as follows:
Power Supply Ratings:
Rating A: 105-125 volts, 50-60 cycles, 80 watts
Rating B: 105-125 volts, 25-60 cycles, 80 watts

One final piece of info that might be helpful - the manual indicates that the pilot lights used for lighting the tuner dial are 6.3 volts.

:No problem. All you have to do is search the power transformer section of their site, or order their catologue. They WILL have an appropriate transformer for you. This will be a lot easier than trying to search for an original. Furthermore, you can be guaranteed that the transformer will be in new condition, and will operate properly. Make sure that the physical dimentions and mounting method used in your radio can be had with the new replacement transformer. If you cannot find a transformer with the proper mounting dimentions and that mounts the way you like (horizontally, vertically, etc.), sometimes you can modify the transformer, or perhaps drill different holes in the chassis. If the new transformer will fit on the chassis, regardless of its position, and also allow all of the lead wires to go safely into the chassis without being exposed, etc., chances are, even if they don't have an exact replacement, you can make something else do. They do have a large line of transformers, though, including some that may not even be listed in their catologue, so you will likely find something that works for you.
:
:T.
:
::
::Thomas, thanks for the info. I posted another message dated 11/22/04 with additional info I gathered since my first message. I'll check out the tubesandmore.com site to see if they can help. Tks again
::
::
::
::
::
:::http://www.nostalgiaair.org/PagesByModel/970/M0028970.pdf
:::
:::This is the info you need for voltages, schematic, etc. It's listed under Canadian General Electric in the Resources section of this web site.
:::
:::Voltages are listed. If you can, print a copy on regular typewriter paper, but also print an enlarged copy. Sometimes you can get the diagrams to print out on 8 or 10 pieces of paper. Then you trim and glue the papers together to make a really big and easy to read diagram.
:::
:::To determine the current requirements of the new power transformer, determine the filament current requirements of each tube. Consult a tube manual for this. You will need a 5 volt filament winding for the 5Y4, and a 6.3 volt filament winding for all the other tubes and pilot lights. The 5 volt filament winding's current rating can be determined simply by the current drawn by the 5Y4 tube. You must add up all the other currents for the other tubes for the 6.3 volt winding. To determine how much current is drawn by the high voltage winding, do the following: FOR EACH TUBE SEPARATELY, multiply its filament current rating by its filament voltage rating. This will give you the WATTAGE drawn by each tube filament. Add these wattages up. Subtract this number from the TOTAL RADIO WATTAGE listed on the label on the back of the set. The number you come up with will be the remaining wattage drawn by all of the tubes' plates and screen grids (the current delivered by the high voltage winding of the transformer). Take this number and divide it by the voltage found on the cathode of the 5Y4 tube. This will give you the AMPERAGE drawn by all the tubes' screen grids and plates. Multiply this number by 1,000 to get the M.A. rating you need for your transformer. The voltage rating of each half of the high voltage winding will be listed on the plate pins of the 5Y4 tube in the circuit diagram. (315 volts--630 volts total divided by two) Since your radio has 315 volts listed, you may purchase a transformer with a 630 volt center tapped HV coil, or if one cannot be found, a 650 will probably do well. This will give you 325 volts per side, which is acceptable.
:::
:::www.tubesandmore.com is a good source for transformers and other radio components. They also have catologues that can be mailed to you. They go by the name of Antique Electronics Supply.
:::
:::Thomas
:::
::::Hello -- need some assistance if anyone can help. Have a Canadian General Electric Model E81 radio and am looking for a power transformer. New to this so I need help as to where to get started on rebuilding this unit. If you can point me in the right direction it would be much appreciated. Tks

11/23/2004 5:21:30 PMThomas Dermody
Ha! They sure are worried about liability! That sucks! They used to be great! I need to know all of the tubes used in YOUR set....to be sure against the circuit diagram. I'll let you know what you need in a bit.....gotta run for a chemistry exam.

Peace,

T.

11/23/2004 9:50:52 PMThomas Dermody
Just a question. Why do you feel that you must replace the power transformer?

I am going to assume that your radio has the 6E5 tuning indicator.


Tube Voltage Amperage Wattage
5Z4 5.0 2.0 10

6F6 6.3 .7 4.41
6F5 6.3 .3 1.89
6H6 6.3 .3 1.89
6K7 6.3 .3 1.89
6J7 6.3 .3 1.89
6L7 6.3 .3 1.89
6E5 6.3 .3 1.89
Pilot #44 6.3 .25 1.575
Pilot #44 6.3 .25 1.575

Total Filament Amperage Total Filament Wattage
5.0 volts 2.0 All Tubes
6.3 volts 3.0 28.9

Total Radio Consumption Total Plate Consumption
80 watts - 28.9 watts = 51.1 watts

Plate Voltage Plate Amperage thru' 5Z4
315 315 / 51.1 = .162

Plate MA
.162 x 1000 = 162


Total Transformer Requirements
6.3 volt winding @ 3.0 amperes
5.0 volt winding @ 2.0 amperes
315-0-315 volt winding @ .162 amperes (162 MA)
117 volt primary, 50/60 cycles

If your area has another frequency besides 50 or 60 cycles, then you will have to contact Antique Electronic Supply for a different transformer. Their transformers listed are only for 50 or 60 cycle current.

The transformers they have listed that will likely fit your needs:

P-T273CZ Hammond
-or-
P-T24R87 Thordarson
Both:
6.3 volt, 5 ampere
5.0 volt, 3 ampere
325-0-325 volt, 150 MA <<150 MA is as close as they get, and should work well.
These are vertical mounting transformers, mounting 2 1/2 by 2 1/2 inches. For horizontal mounting, you will have to cut off the ears on the covers, and then figure out a way to mount horizontally. Leads must come out of one cover in order to do this. If the leads come out of two different sides of the transformer, then you will have to mount it vertically.

Good luck,

Thomas

11/23/2004 9:55:08 PMThomas Dermody
Well, that sucks. I had everything separated into neat columns, and it squished all together. Well, I separated everything with stars this time (*).

T.

:Just a question. Why do you feel that you must replace the power transformer?
:
:I am going to assume that your radio has the 6E5 tuning indicator.
:
:
:Tube Voltage Amperage Wattage
:5Z4 5.0 * 2.0 * 10
:
:6F6 6.3 * .7 * 4.41
:6F5 6.3 * .3 * 1.89
:6H6 6.3 * .3 * 1.89
:6K7 6.3 * .3 * 1.89
:6J7 6.3 * .3 * 1.89
:6L7 6.3 * .3 * 1.89
:6E5 6.3 * .3 * 1.89
:Pilot #44 6.3 * .25 * 1.575
:Pilot #44 6.3 * .25 * 1.575
:
:Total Filament Amperage * Total Filament Wattage
:5.0 volts 2.0 * All Tubes
:6.3 volts 3.0 * 28.9
:
:Total Radio Consumption * Total Plate Consumption
:80 watts ********* - 28.9 watts = 51.1 watts
:
:Plate Voltage * Plate Amperage thru' 5Z4
:315********************315 / 51.1 = .162
:
: Plate MA
:.162 x 1000 = 162
:
:
:Total Transformer Requirements
:6.3 volt winding @ 3.0 amperes
:5.0 volt winding @ 2.0 amperes
:315-0-315 volt winding @ .162 amperes (162 MA)
:117 volt primary, 50/60 cycles
:
:If your area has another frequency besides 50 or 60 cycles, then you will have to contact Antique Electronic Supply for a different transformer. Their transformers listed are only for 50 or 60 cycle current.
:
:The transformers they have listed that will likely fit your needs:
:
:P-T273CZ Hammond
: -or-
:P-T24R87 Thordarson
:Both:
:6.3 volt, 5 ampere
:5.0 volt, 3 ampere
:325-0-325 volt, 150 MA <<150 MA is as close as they get, and should work well.
:These are vertical mounting transformers, mounting 2 1/2 by 2 1/2 inches. For horizontal mounting, you will have to cut off the ears on the covers, and then figure out a way to mount horizontally. Leads must come out of one cover in order to do this. If the leads come out of two different sides of the transformer, then you will have to mount it vertically.
:
:Good luck,
:
:Thomas

11/25/2004 5:21:34 PMThomas Dermody
You can also try this out. This is a link to a slightly more powerful transformer I found on their site. It has 180 MA for the high voltage winding.

http://www.tubesandmore.com/new/scripts/silverware.exe/moreinfo@d:/dfs/elevclients/cemirror/ELEVATOR.FXP?item=P-TF22723

11/27/2004 2:29:22 AMThomas Dermody
Something to think about when purchasing a transformer for your radio that I just remembered: As I recall, I stated that your high voltage winding should be a 162 milliampere winding. Then I looked in my catologue and could only find 150 milliampere transformers. Of course, later I listed a 180 milliampere transformer that I found on their web site (my catologue is a year old, and they just got a new line of transformers in). What I forgot, though, is that the 150 milliampere transformer will probably work just fine for your radio, and that is probably all that your radio will actually consume in the high voltage section. When I did my calculations to divide up the different current requirements throughout the radio based on the wattage consumed by the radio as listed on the label information, I was assuming that all power consumption is 100% efficient, and all is used by the various radio components. What I did not take into consideration is that power transformers are usually only 90 to 95% efficient. Some of the wattage listed on the label in back of your radio is actually consumed by the power transformer itself. That said, instead of saying that the radio consumes the full 80 watts, it more likely only consumes 72 to 76 watts, the remaining 4 to 8 watts being consumed by the transformer itself. Key proof of this is to remove every tube and bulb from an AC radio of good condition, and then plug the radio in series with a 7 watt nightlight bulb. The bulb should glow even though there is nothing in the radio drawing power from the transformer.

Doing all calculations from 72 to 76 watts will bring you a slightly lower current requirement for the high voltage section. That said, you should likely be fine with a 150 milliampere high voltage winding. I will eat my shoe if I am wrong. A properly selected transformer, with normal operation, will get comfortably, if not cozily, warm. It should not burn your fingers. It will satisfactorily warm freezing cold hands with a wonderful feeling, though.

Thomas

11/29/2004 2:30:29 AMThomas Dermody
ALL of the above replies from me have all the specifications and other technical information you will need in purchasing a new transformer. Doesn't get much better than this.


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