Hello All,
I'm working on a Philco 46-480 that someone "fixed" before I got to it. They replaced the transformer between the second IF amp 7H7 and the 6H6. There is no audio from the tuner due to this. Evedently they never got it to work.
I have it connected correctly for the correct transformer. There is no orange wire from T5 anymore. In fact, there is no T5. Only T6 was replaced. If someone knows where I can find an IF transformer that will work or how to get this radio to work with this "replacement" transformer, please let me know.

Thanks,

Dave...
Riders - Philco Page 15-15
All paper and filter capacitors have been replaced.

Hello All,
Actually, that replacement transformer that's in there does work, however, there is no FM audio because, this isn't the correct transformer and one transformer is still missing. Sorry if I made a mistake in the subject. I hope that no body was offended by it. Anway, I would like to know what the part number for the missing transformer (T5-T6) is.
Please help if you can.

Thanks,

Dave...
:Hello All,
: I'm working on a Philco 46-480 that someone "fixed" before I got to it. They replaced the transformer between the second IF amp 7H7 and the 6H6. There is no audio from the tuner due to this. Evedently they never got it to work.
: I have it connected correctly for the correct transformer. There is no orange wire from T5 anymore. In fact, there is no T5. Only T6 was replaced. If someone knows where I can find an IF transformer that will work or how to get this radio to work with this "replacement" transformer, please let me know.
:
:Thanks,
:
:Dave...
:Riders - Philco Page 15-15
:All paper and filter capacitors have been replaced.

Hi Dave

Check this list. Probably something like 1479-077 is what you need?

http://www.oldradioparts.com/2a6fla.txt

Norm

:Hello All,
: Actually, that replacement transformer that's in there does work, however, there is no FM audio because, this isn't the correct transformer and one transformer is still missing. Sorry if I made a mistake in the subject. I hope that no body was offended by it. Anway, I would like to know what the part number for the missing transformer (T5-T6) is.
: Please help if you can.
:
:Thanks,
:
:Dave...
::Hello All,
:: I'm working on a Philco 46-480 that someone "fixed" before I got to it. They replaced the transformer between the second IF amp 7H7 and the 6H6. There is no audio from the tuner due to this. Evedently they never got it to work.
:: I have it connected correctly for the correct transformer. There is no orange wire from T5 anymore. In fact, there is no T5. Only T6 was replaced. If someone knows where I can find an IF transformer that will work or how to get this radio to work with this "replacement" transformer, please let me know.
::
::Thanks,
::
::Dave...
::Riders - Philco Page 15-15
::All paper and filter capacitors have been replaced.

One more thing.. Your transformer may be for AM & FM in one can. If you don't see what you need call Gary at PTOP.

Norm

:Hi Dave
:
: Check this list. Probably something like 1479-077 is what you need?
:
:http://www.oldradioparts.com/2a6fla.txt
:
:Norm
:
: :Hello All,
:: Actually, that replacement transformer that's in there does work, however, there is no FM audio because, this isn't the correct transformer and one transformer is still missing. Sorry if I made a mistake in the subject. I hope that no body was offended by it. Anway, I would like to know what the part number for the missing transformer (T5-T6) is.
:: Please help if you can.
::
::Thanks,
::
::Dave...
:::Hello All,
::: I'm working on a Philco 46-480 that someone "fixed" before I got to it. They replaced the transformer between the second IF amp 7H7 and the 6H6. There is no audio from the tuner due to this. Evedently they never got it to work.
::: I have it connected correctly for the correct transformer. There is no orange wire from T5 anymore. In fact, there is no T5. Only T6 was replaced. If someone knows where I can find an IF transformer that will work or how to get this radio to work with this "replacement" transformer, please let me know.
:::
:::Thanks,
:::
:::Dave...
:::Riders - Philco Page 15-15
:::All paper and filter capacitors have been replaced.

Norm,
That is right. One part of the original secondary connects to the discriminator and another connects to the AM detector on the 6SQ7. But with the replacement transformer, I had to connect the one end of the single secondary to both places. Now I can hear AM and Short Wave but not FM.

Thanks Again,

Dave...
:One more thing.. Your transformer may be for AM & FM in one can. If you don't see what you need call Gary at PTOP.
:
:Norm
:
::Hi Dave
::
:: Check this list. Probably something like 1479-077 is what you need?
::
::http://www.oldradioparts.com/2a6fla.txt
::
::Norm
::
:: :Hello All,
::: Actually, that replacement transformer that's in there does work, however, there is no FM audio because, this isn't the correct transformer and one transformer is still missing. Sorry if I made a mistake in the subject. I hope that no body was offended by it. Anway, I would like to know what the part number for the missing transformer (T5-T6) is.
::: Please help if you can.
:::
:::Thanks,
:::
:::Dave...
::::Hello All,
:::: I'm working on a Philco 46-480 that someone "fixed" before I got to it. They replaced the transformer between the second IF amp 7H7 and the 6H6. There is no audio from the tuner due to this. Evedently they never got it to work.
:::: I have it connected correctly for the correct transformer. There is no orange wire from T5 anymore. In fact, there is no T5. Only T6 was replaced. If someone knows where I can find an IF transformer that will work or how to get this radio to work with this "replacement" transformer, please let me know.
::::
::::Thanks,
::::
::::Dave...
::::Riders - Philco Page 15-15
::::All paper and filter capacitors have been replaced.

Norm,
Does this have the same number of connections as the original I. F. transformer? If it does, and I have the schematic for it, you are right, it should work fine.

Thanks,

Dave...
:Hi Dave
:
: Check this list. Probably something like 1479-077 is what you need?
:
:http://www.oldradioparts.com/2a6fla.txt
:
:Norm
:
: :Hello All,
:: Actually, that replacement transformer that's in there does work, however, there is no FM audio because, this isn't the correct transformer and one transformer is still missing. Sorry if I made a mistake in the subject. I hope that no body was offended by it. Anway, I would like to know what the part number for the missing transformer (T5-T6) is.
:: Please help if you can.
::
::Thanks,
::
::Dave...
:::Hello All,
::: I'm working on a Philco 46-480 that someone "fixed" before I got to it. They replaced the transformer between the second IF amp 7H7 and the 6H6. There is no audio from the tuner due to this. Evedently they never got it to work.
::: I have it connected correctly for the correct transformer. There is no orange wire from T5 anymore. In fact, there is no T5. Only T6 was replaced. If someone knows where I can find an IF transformer that will work or how to get this radio to work with this "replacement" transformer, please let me know.
:::
:::Thanks,
:::
:::Dave...
:::Riders - Philco Page 15-15
:::All paper and filter capacitors have been replaced.

There should be two different coils within the can, or two parts to each coil--the primary and secondary. If the coils are slug tuned, it is unlikely that the primary and secondary will have two parts, as it will be impossible to lock in on both IF frequencies with only one slug per coil. At any rate, 10.7 MC requires a much smaller coil than 455 KC. That said, there is absolutely no way that one coil serves both purposes unless it has a large part and a small part, and is not slug tuned......or if somehow they managed to get a high impedance 455 KC coil to tune to 10.7 MC.

If you look at the original diagram, you will see that there are two sets of coils in each can. They are wired in series because the FM coil will not do anything when wired in series with the AM coil. When FM is wanted, the AM coil is shorted out and then the FM coil functions. The reason why this is possible is that the AM coil acts like a choke when in series with the FM coil, and does not allow the FM coil to resonate. The FM coil, however, which is of very low impedance, passes low frequencies quite well, allowing the AM coil to operate. With this set-up, it is not necessary to completely connect and disconnect IF transformers to select between high frequency FM and low frequency AM. Instead, all that is necessary is to either short out or unshort the AM transformer coils, as was already mentioned above. Shorting them out passes current directly to the FM coils, allowing them to function at the frequency for which they are tuned.

At any rate, you cannot use an ordinary IF transformer with only one primary and secondary, of either the 455 KC or 10.7 MC type. It sounds like you are using a 455 KC type, which is why the AM works. You must either use a unit that has two different transformers in one can, or otherwise use a unit with a single transformer in the can that fits in place of the old transformer. Then use a separate IF transformer for the other band and mount it under the chassis. Norm seems to have found you a part number for a combination unit, however. Also, for frequency modulation, it is usually necessary to have a center tapped secondary on the last IF transformer. Discrimination is a bit different than AM detection. You cannot simply wire an untapped coil to the discriminator diodes. Wire in the new transformer(s) EXACTLY as stated in the diagram. This is the only way they will work.

Thomas

:There should be two different coils within the can, or two parts to each coil--the primary and secondary. If the coils are slug tuned, it is unlikely that the primary and secondary will have two parts, as it will be impossible to lock in on both IF frequencies with only one slug per coil. At any rate, 10.7 MC requires a much smaller coil than 455 KC. That said, there is absolutely no way that one coil serves both purposes unless it has a large part and a small part, and is not slug tuned......or if somehow they managed to get a high impedance 455 KC coil to tune to 10.7 MC.
:
:If you look at the original diagram, you will see that there are two sets of coils in each can. They are wired in series because the FM coil will not do anything when wired in series with the AM coil. When FM is wanted, the AM coil is shorted out and then the FM coil functions. The reason why this is possible is that the AM coil acts like a choke when in series with the FM coil, and does not allow the FM coil to resonate. The FM coil, however, which is of very low impedance, passes low frequencies quite well, allowing the AM coil to operate. With this set-up, it is not necessary to completely connect and disconnect IF transformers to select between high frequency FM and low frequency AM. Instead, all that is necessary is to either short out or unshort the AM transformer coils, as was already mentioned above. Shorting them out passes current directly to the FM coils, allowing them to function at the frequency for which they are tuned.
:
:At any rate, you cannot use an ordinary IF transformer with only one primary and secondary, of either the 455 KC or 10.7 MC type. It sounds like you are using a 455 KC type, which is why the AM works. You must either use a unit that has two different transformers in one can, or otherwise use a unit with a single transformer in the can that fits in place of the old transformer. Then use a separate IF transformer for the other band and mount it under the chassis. Norm seems to have found you a part number for a combination unit, however. Also, for frequency modulation, it is usually necessary to have a center tapped secondary on the last IF transformer. Discrimination is a bit different than AM detection. You cannot simply wire an untapped coil to the discriminator diodes. Wire in the new transformer(s) EXACTLY as stated in the diagram. This is the only way they will work.
:
:
:Thomas

Tomas,

I wonder why Philco used a 9.1 MHz IF for FM in this radio instead of 10.7 MHz?

Radiodoc

Well, depending on the parts available, whether manufactured by them or not, they may have actually needed this different IF frequency. Different frequencies give different dial spacing. They may have had better luck with this frequency? There are many reasons for this, and I'm sure if I hit on a whole bunch, I'd still miss their reason. For instance, sometimes a different IF frequency is used because of harmonic problems and interference problems due to transmitters operating at the IF frequency, though this can usually be cured with a wave trap on the front end or a front end RF tuner.

Anyway, lots of reasons. You'd have to do research on their company and FM radios manufactured during that time by Philco.

Thomas