Hi! I am a newbie to the site (and antique radio), and need some help.
I recently purchased a Crosley Model 819M (chassis #819). The radio does not work, and unfortunately has very different tubes that the schematics I have found online. Not only are the tubes different, but apparently this chassis is a different animal from the 819's listed - it has 7 tubes as opposed to the 8 on the posted schematics.
Any info would be greatly appreciated!

Thanks,

Roger

:Hi! I am a newbie to the site (and antique radio), and need some help.
:I recently purchased a Crosley Model 819M (chassis #819). The radio does not work, and unfortunately has very different tubes that the schematics I have found online. Not only are the tubes different, but apparently this chassis is a different animal from the 819's listed - it has 7 tubes as opposed to the 8 on the posted schematics.
:Any info would be greatly appreciated!
hi there are two different types of 819m's one uses two 5y3's the other uses two 25z6's they are in rider's 11 under crosley 36to38. butch
:
:Thanks,
:
:Roger

::Hi! I am a newbie to the site (and antique radio), and need some help.
::I recently purchased a Crosley Model 819M (chassis #819). The radio does not work, and unfortunately has very different tubes that the schematics I have found online. Not only are the tubes different, but apparently this chassis is a different animal from the 819's listed - it has 7 tubes as opposed to the 8 on the posted schematics.
::Any info would be greatly appreciated!
:hi there are two different types of 819m's one uses two 5y3's the other uses two 25z6's they are in rider's 11 under crosley 36to38. butch
::
::Thanks,
::
::Roger

Butch,

I found the schematics - that was never the problem. It seems though that I have a strange variant that has only 7 tubes instead of the 8 called for in the published schematics. That's what I was hoping someone would have an answer to. Roger

Hi Roger,
Can you list the tube types used in your radio? Also, how many knobs are on the front panel? This might help in finding a schematic.
BR,
Dave

:Hi Roger,
:Can you list the tube types used in your radio? Also, how many knobs are on the front panel? This might help in finding a schematic.
:BR,
:Dave

Hi Dave,
The tubes present are (FROM LEFT REAR TO THE FRONT WHILE FACING THE FRONT OF THE CABINET) 6SK7 6K6GT MISSING 6AC7 6SQ7 6K8GT 5Y3GT The right rear tube socket is covered with a soldered on cover. There are
4 knobs on the front of the chassis.
Thanks! Roger

Hi Roger,
As Butch mentioned, check your radio against the schematic here at Nostalgiaair. Maybe it was modified in a past repair?
That covered-up socket is one clue the radio may have been modified.
BR,
Dave

If the chassis looks to be original (correct dial, control shafts, etc., then it was likely modified. If it is the transformer model, and the transformer blew out, then it was likely replaced with a more conventional transformer with a 6.3 volt winding for most of the tubes and a 5.0 volt winding for the rectifier (one 5Y3 currently being used....originally 2 5Y3 tubes). Your original configuration, there was a tap in the high voltage section to supply all of the audio and RF tube filaments strung in series. The supply for the rectifier tube filaments was about 10 volts as they were also strung in series. Crosley liked to do some very interesting things like this. The phase inversion transformer in your radio, using only one winding with a center tap instead of the conventional primary and secondary, is another example of this (push-pull audio section). In my Crosley, phase inversion was tapped off the screen grid of the first power output tube and sent to the other one. This, too, is not a conventional method, but it works well.

At any rate, if a more conventional transformer was used as a replacement, tubes with 6.3 volt filaments would have to be used, and the filaments would have to be wired in parallel instead of series (pins 2 and 7 on most tubes and 7 and 8 on the 6SQ7). 6K6 makes a good replacement for the 25L6. It is wired exactly the same and has an output comparable to the 25L6, but has a 6.3 volt filament instead of a 25 volt filament. You could also use 6V6 tubes, but biasing may be wrong for these tubes. Now, you only listed 1 6K6 tube, so I'll just assume that you forgot about the other one, or perhaps that socket is empty. You only listed 6 tubes and said that there were 7 (as compared to the original 8), so I am assuming that you forgot about the other power output tube (6K6).

As for the rectifier situation, conventional power transformers, unless of the high power variety (capable of powering the filament of a 5U4 tube), are only capable of powering one 5Y3 filament. Actually, your radio only needs one 5Y3 tube to operate properly at any rate. The AC-DC version (25Z6, no power transformer, filaments in series), used 2 rectifiers with 25 volt filaments. With all of the tubes listed, the filaments would add up to around line voltage and could be operated in series with no ballast resistor. There really is no need for 2 25Z6 tubes. The extra 25 volt filament just helps to eliminate a ballast resistor, and the extra rectifier gives the radio a little extra power that is not really needed. The AC version, probably using the same chassis or at least using the same tube count for advertising purposes, probably used 2 5Y3 tubes for the reasons just mentioned. There isn't really a need for 2 5Y3 tubes.

So......if your power transformer was replaced, this would be the reason for the above changes to the radio. You are not likely to ever find an original power transformer for your radio unless you have one custom made or find one from another set. Your set will work fine, though, with a conventional power transformer. If you wish to have 2 5Y3 tubes again, you may purchase a 3 ampere 5.0 volt filament transformer from Antique Electronic Supply (www.tubesandmore.com). Use this to power your other 5Y3 tube (you'll have to uncover that socket). Mount the transformer under the chassis so it will not be seen. Connect a wire from pin 4 of one 5Y3 to pin 4 of the other. Do the same for pin 6. DO NOT CONNECT THE TWO FILAMENTS IN PARALLEL USING TWO SEPARATE FILAMENT TRANSFORMERS. However, connect a wire from pin 8 of one tube to pin 8 of the other. This will connect the cathodes together. DO NOT EVER CONNECT EITHER FILAMENT SUPPLY FOR THE RECTIFIERS TO THE CHASSIS IN ANY WAY.

As for the 6AC7 tube, this is a fairly good replacement for the 6SK7 tube. It may have been used to replace one of the 6SK7 tubes in your radio. If the chassis is marked with 6AC7, and does not look like the original chassis, then you do have the wrong chassis, but if there is a 6AC7 tube in one of the 6SK7 sockets, assume that this is just a substitute replacement. The 6AC7 will work fine in either of the 6SK7 sockets on your radio.

Check your chassis against the pictures shown in the Resources section of this web page. Go to Crosley Radio Corp. and then to 819. PRINT OUT BOTH THE INFORMATION I JUST GAVE YOU AND THE DIAGRAMS FOR YOUR SET. GO OVER ALL OF THIS THOROUGHLY WHILE LOOKING AT YOUR SET. This will tell you what you are looking at. When operating your radio, check the voltages against the originals. If you come up with different voltages, let me know what they are. It is possible that someone replaced the power transformer with one with much higher voltages. It is possible to operate this radio with a higher power transformer, considering that the capacitors can handle it, but they and other components must be replaced for this to be possible. If original value components are used, the voltages must be near the original ones.

Take care,

Thomas

::Hi Roger,
::Can you list the tube types used in your radio? Also, how many knobs are on the front panel? This might help in finding a schematic.
::BR,
::Dave
:
:Hi Dave,
:The tubes present are (FROM LEFT REAR TO THE FRONT WHILE FACING THE FRONT OF THE CABINET) 6SK7 6K6GT MISSING 6AC7 6SQ7 6K8GT 5Y3GT The right rear tube socket is covered with a soldered on cover. There are
:4 knobs on the front of the chassis.
:Thanks! Roger

Thomas,

Thanks so much for the detailed answer. The reason I did not mention a second 6K6 tube is because the socket was empty, and I wasn't sure what tube should be there.

I will test the chassis as you suggested, and will go with the tubes present (if it works), but would ultimately like to restore the set to original specs, which as you said might have to include a custom wound transformer (no one said this hobby would be cheap!).

Once again, thanks to all of you who took the time to help me. You have a wonderful organization, and I for one am grateful.

Have a Wonderful Holiday, and a Happy New Year!

Roger Oppenheimer

Another trick you could do is obtain a power transformer capable of driving all the 6.3 volt filaments in parallel. This transformer should also have a 5 to 6 ampere 5.0 volt winding capable of driving two 5Y3 filaments in parallel. I think each 5Y3 filament is like 2.0 amperes or something like that. At any rate, a transformer like this is easily had just like the one that is already in your set. Now, to have the original 25L6 tubes, obtain, if you can, a 25 or 50 volt filament transformer capable of supplying about 1 ampere. Wire the filaments in series for the former voltage and parallel for the latter. The transformer could be mounted under the chassis where noone would see.

Anyway, if you can restore it to all original, though that would be great. There are lots of alternate options, but if you can get the original transformer, that'll be great. Good luck and have fun with this radio.

Take care,

Thomas

:If the chassis looks to be original (correct dial, control shafts, etc., then it was likely modified. If it is the transformer model, and the transformer blew out, then it was likely replaced with a more conventional transformer with a 6.3 volt winding for most of the tubes and a 5.0 volt winding for the rectifier (one 5Y3 currently being used....originally 2 5Y3 tubes). Your original configuration, there was a tap in the high voltage section to supply all of the audio and RF tube filaments strung in series. The supply for the rectifier tube filaments was about 10 volts as they were also strung in series. Crosley liked to do some very interesting things like this. The phase inversion transformer in your radio, using only one winding with a center tap instead of the conventional primary and secondary, is another example of this (push-pull audio section). In my Crosley, phase inversion was tapped off the screen grid of the first power output tube and sent to the other one. This, too, is not a conventional method, but it works well.
:
:At any rate, if a more conventional transformer was used as a replacement, tubes with 6.3 volt filaments would have to be used, and the filaments would have to be wired in parallel instead of series (pins 2 and 7 on most tubes and 7 and 8 on the 6SQ7). 6K6 makes a good replacement for the 25L6. It is wired exactly the same and has an output comparable to the 25L6, but has a 6.3 volt filament instead of a 25 volt filament. You could also use 6V6 tubes, but biasing may be wrong for these tubes. Now, you only listed 1 6K6 tube, so I'll just assume that you forgot about the other one, or perhaps that socket is empty. You only listed 6 tubes and said that there were 7 (as compared to the original 8), so I am assuming that you forgot about the other power output tube (6K6).
:
:As for the rectifier situation, conventional power transformers, unless of the high power variety (capable of powering the filament of a 5U4 tube), are only capable of powering one 5Y3 filament. Actually, your radio only needs one 5Y3 tube to operate properly at any rate. The AC-DC version (25Z6, no power transformer, filaments in series), used 2 rectifiers with 25 volt filaments. With all of the tubes listed, the filaments would add up to around line voltage and could be operated in series with no ballast resistor. There really is no need for 2 25Z6 tubes. The extra 25 volt filament just helps to eliminate a ballast resistor, and the extra rectifier gives the radio a little extra power that is not really needed. The AC version, probably using the same chassis or at least using the same tube count for advertising purposes, probably used 2 5Y3 tubes for the reasons just mentioned. There isn't really a need for 2 5Y3 tubes.
:
:So......if your power transformer was replaced, this would be the reason for the above changes to the radio. You are not likely to ever find an original power transformer for your radio unless you have one custom made or find one from another set. Your set will work fine, though, with a conventional power transformer. If you wish to have 2 5Y3 tubes again, you may purchase a 3 ampere 5.0 volt filament transformer from Antique Electronic Supply (www.tubesandmore.com). Use this to power your other 5Y3 tube (you'll have to uncover that socket). Mount the transformer under the chassis so it will not be seen. Connect a wire from pin 4 of one 5Y3 to pin 4 of the other. Do the same for pin 6. DO NOT CONNECT THE TWO FILAMENTS IN PARALLEL USING TWO SEPARATE FILAMENT TRANSFORMERS. However, connect a wire from pin 8 of one tube to pin 8 of the other. This will connect the cathodes together. DO NOT EVER CONNECT EITHER FILAMENT SUPPLY FOR THE RECTIFIERS TO THE CHASSIS IN ANY WAY.
:
:As for the 6AC7 tube, this is a fairly good replacement for the 6SK7 tube. It may have been used to replace one of the 6SK7 tubes in your radio. If the chassis is marked with 6AC7, and does not look like the original chassis, then you do have the wrong chassis, but if there is a 6AC7 tube in one of the 6SK7 sockets, assume that this is just a substitute replacement. The 6AC7 will work fine in either of the 6SK7 sockets on your radio.
:
:Check your chassis against the pictures shown in the Resources section of this web page. Go to Crosley Radio Corp. and then to 819. PRINT OUT BOTH THE INFORMATION I JUST GAVE YOU AND THE DIAGRAMS FOR YOUR SET. GO OVER ALL OF THIS THOROUGHLY WHILE LOOKING AT YOUR SET. This will tell you what you are looking at. When operating your radio, check the voltages against the originals. If you come up with different voltages, let me know what they are. It is possible that someone replaced the power transformer with one with much higher voltages. It is possible to operate this radio with a higher power transformer, considering that the capacitors can handle it, but they and other components must be replaced for this to be possible. If original value components are used, the voltages must be near the original ones.
:
:Take care,
:
:Thomas
:
:::Hi Roger,
:::Can you list the tube types used in your radio? Also, how many knobs are on the front panel? This might help in finding a schematic.
:::BR,
:::Dave
::
::Hi Dave,
::The tubes present are (FROM LEFT REAR TO THE FRONT WHILE FACING THE FRONT OF THE CABINET) 6SK7 6K6GT MISSING 6AC7 6SQ7 6K8GT 5Y3GT The right rear tube socket is covered with a soldered on cover. There are
::4 knobs on the front of the chassis.
::Thanks! Roger