I have a model 706. I have a schematic which is fairly worthless because the text is not readable. Question. The speaker has four wires, two with pins and two bare. I took the lid off of the radio and on the right rear of the chassis there appears to be two female connections for the pins. On the left rear there is a terminal strip with four screws. I assume that the bare pair of wires go to two of these. Help, which ones! Any info on this radio appreciated. I would like to get in there and rebuild it soon. Also does anyone have the value of the dual capacitor?

Eric,
I believe the 2 pin wires either can be used in the 2 female phone plugs or under the "N" and "P" terminals (which are the same connected by a run of wire.) Both N and P and the phone terms come off the plate of the 71a's..
The 2 bare leads i am assuming go to term "G".
"A" is antenna..
I dont have the original speaker with mine and it's put away right now, but i recall you should be able to get audio from either one of the 71a plates with a ground from an everyday output tx..

Those values in the large copper can are unknown to me, but i replaced mine with a (2) 22mf 450 and it works just fine.. I suspect the originals are lower than that, typically 8 or 12..
David

: I have a model 706. I have a schematic which is fairly worthless because the text is not readable. Question. The speaker has four wires, two with pins and two bare. I took the lid off of the radio and on the right rear of the chassis there appears to be two female connections for the pins. On the left rear there is a terminal strip with four screws. I assume that the bare pair of wires go to two of these. Help, which ones! Any info on this radio appreciated. I would like to get in there and rebuild it soon. Also does anyone have the value of the dual capacitor?

Eric, i you have time could you send a drawing of your internal speaker connections? Maybe someone could shed some light.. is this a push-pull setup? seems early..
The grids are fed from either end of the last audio transformer and the input is center-tapped.
David

: Eric,
: I believe the 2 pin wires either can be used in the 2 female phone plugs or under the "N" and "P" terminals (which are the same connected by a run of wire.) Both N and P and the phone terms come off the plate of the 71a's..
: The 2 bare leads i am assuming go to term "G".
: "A" is antenna..
: I dont have the original speaker with mine and it's put away right now, but i recall you should be able to get audio from either one of the 71a plates with a ground from an everyday output tx..
:
: Those values in the large copper can are unknown to me, but i replaced mine with a (2) 22mf 450 and it works just fine.. I suspect the originals are lower than that, typically 8 or 12..
: David

:
: : I have a model 706. I have a schematic which is fairly worthless because the text is not readable. Question. The speaker has four wires, two with pins and two bare. I took the lid off of the radio and on the right rear of the chassis there appears to be two female connections for the pins. On the left rear there is a terminal strip with four screws. I assume that the bare pair of wires go to two of these. Help, which ones! Any info on this radio appreciated. I would like to get in there and rebuild it soon. Also does anyone have the value of the dual capacitor?

Erik,
here is my e mail..
Ps, i hope you have lots of money if you decide to re-tube that thing..

: Eric, i you have time could you send a drawing of your internal speaker connections? Maybe someone could shed some light.. is this a push-pull setup? seems early..
: The grids are fed from either end of the last audio transformer and the input is center-tapped.
: David

: : Eric,
: : I believe the 2 pin wires either can be used in the 2 female phone plugs or under the "N" and "P" terminals (which are the same connected by a run of wire.) Both N and P and the phone terms come off the plate of the 71a's..
: : The 2 bare leads i am assuming go to term "G".
: : "A" is antenna..
: : I dont have the original speaker with mine and it's put away right now, but i recall you should be able to get audio from either one of the 71a plates with a ground from an everyday output tx..
: :
: : Those values in the large copper can are unknown to me, but i replaced mine with a (2) 22mf 450 and it works just fine.. I suspect the originals are lower than that, typically 8 or 12..
: : David

:
: :
: : : I have a model 706. I have a schematic which is fairly worthless because the text is not readable. Question. The speaker has four wires, two with pins and two bare. I took the lid off of the radio and on the right rear of the chassis there appears to be two female connections for the pins. On the left rear there is a terminal strip with four screws. I assume that the bare pair of wires go to two of these. Help, which ones! Any info on this radio appreciated. I would like to get in there and rebuild it soon. Also does anyone have the value of the dual capacitor?

Thanks for the info. The 22mF caps you are mentioning. Is that actually m(milli) or u(micro) farad. I belive that in the good old days these were interchangeable terms. If you want me to ohm out the speaker connections, not a problem, I will take a look at it this weekend. I used to restore vintage jukes and they used electro dynamic speakers. Apparently permanent magnets were not avail. so they ran the DC power bus through a coil in the speaker to create a magnetic field. I suspect the speaker for this is identical in operation although I have not looked into too closely yet. Speaking of tubes for this guy. There is a resident set inside but I have no idea of the condition at this time. What would you suspect a set would cost. You have my curiosity up now?

: Erik,
: here is my e mail..
: Ps, i hope you have lots of money if you decide to re-tube that thing..

:
: : Eric, i you have time could you send a drawing of your internal speaker connections? Maybe someone could shed some light.. is this a push-pull setup? seems early..
: : The grids are fed from either end of the last audio transformer and the input is center-tapped.
: : David

:
: : : Eric,
: : : I believe the 2 pin wires either can be used in the 2 female phone plugs or under the "N" and "P" terminals (which are the same connected by a run of wire.) Both N and P and the phone terms come off the plate of the 71a's..
: : : The 2 bare leads i am assuming go to term "G".
: : : "A" is antenna..
: : : I dont have the original speaker with mine and it's put away right now, but i recall you should be able to get audio from either one of the 71a plates with a ground from an everyday output tx..
: : :
: : : Those values in the large copper can are unknown to me, but i replaced mine with a (2) 22mf 450 and it works just fine.. I suspect the originals are lower than that, typically 8 or 12..
: : : David

: :
: : :
: : : : I have a model 706. I have a schematic which is fairly worthless because the text is not readable. Question. The speaker has four wires, two with pins and two bare. I took the lid off of the radio and on the right rear of the chassis there appears to be two female connections for the pins. On the left rear there is a terminal strip with four screws. I assume that the bare pair of wires go to two of these. Help, which ones! Any info on this radio appreciated. I would like to get in there and rebuild it soon. Also does anyone have the value of the dual capacitor?

Well things have taken an interesting turn. From examining the radio, speaker and illegible schematic the two phone jacks which plug into the right rear of the chassis are for the field coil. The field coil in the speaker measured about 600 ohms DC. As you stated earlier the voice connections go to the two of the four screw terminal on the left rear of the chassis. However in my case there are two small coils in the speaker of ultra fine many hundreds of turns of which one is open. Does anyone have a parts speaker out there?
: Thanks for the info. The 22mF caps you are mentioning. Is that actually m(milli) or u(micro) farad. I belive that in the good old days these were interchangeable terms. If you want me to ohm out the speaker connections, not a problem, I will take a look at it this weekend. I used to restore vintage jukes and they used electro dynamic speakers. Apparently permanent magnets were not avail. so they ran the DC power bus through a coil in the speaker to create a magnetic field. I suspect the speaker for this is identical in operation although I have not looked into too closely yet. Speaking of tubes for this guy. There is a resident set inside but I have no idea of the condition at this time. What would you suspect a set would cost. You have my curiosity up now?

: : Erik,
: : here is my e mail..
: : Ps, i hope you have lots of money if you decide to re-tube that thing..

: :
: : : Eric, i you have time could you send a drawing of your internal speaker connections? Maybe someone could shed some light.. is this a push-pull setup? seems early..
: : : The grids are fed from either end of the last audio transformer and the input is center-tapped.
: : : David

: :
: : : : Eric,
: : : : I believe the 2 pin wires either can be used in the 2 female phone plugs or under the "N" and "P" terminals (which are the same connected by a run of wire.) Both N and P and the phone terms come off the plate of the 71a's..
: : : : The 2 bare leads i am assuming go to term "G".
: : : : "A" is antenna..
: : : : I dont have the original speaker with mine and it's put away right now, but i recall you should be able to get audio from either one of the 71a plates with a ground from an everyday output tx..
: : : :
: : : : Those values in the large copper can are unknown to me, but i replaced mine with a (2) 22mf 450 and it works just fine.. I suspect the originals are lower than that, typically 8 or 12..
: : : : David

: : :
: : : :
: : : : : I have a model 706. I have a schematic which is fairly worthless because the text is not readable. Question. The speaker has four wires, two with pins and two bare. I took the lid off of the radio and on the right rear of the chassis there appears to be two female connections for the pins. On the left rear there is a terminal strip with four screws. I assume that the bare pair of wires go to two of these. Help, which ones! Any info on this radio appreciated. I would like to get in there and rebuild it soon. Also does anyone have the value of the dual capacitor?

Ok Erik,
Thankyou for the info as well..
I really wasnt sure about the speaker type having never seen one for this or being able to locate info. There were metal magnet types in those days (although not permant as most of them could use a recharge by now) such as the RCA 100a..
You might try to work with the open coil wires maybe unwind it and reconnect if the break is not to far from the end.. it is possible it will work with just the one coil connected through..
So.. i guess i need a coil or 600 ohms in place of it.
The field coils also provided humbucking as well from the extra filtering.
I more or less cleaned my 706 up and re capped the supply, replaced the power sw and the cord and got power on it and heard a station briefly through a test speaker on the bench. good enough so it's been up in a closet until i could find out more..So many projects, so little time (and money)

i'm still slightly baffled about how the dual 71's are operating..Anyone?

The caps would be rated in Micro farad, or uF.Electrolytic type. Everything is in mF or percentage of mf unless it's picofarad or god forbid Farad. I am sure now with the field coil the originals would have been much lower than 22..
There is plenty of room in the old can to hide the modern ones inside.
The showbox seems to be more of an upgraded TRF for it's day. Definately heavy Metal!

depends on where you get the tubes..Yours should be ok or acceptable ..usually that's the case.
Here's the breakdown from AES:
4 X #26st @18.50 ea = $74
#27st = $10.10
#80st= $22.90
2x #71a @ $38.20ea=$76.40
Total for NOS=
$183.40 + shipping..

: Well things have taken an interesting turn. From examining the radio, speaker and illegible schematic the two phone jacks which plug into the right rear of the chassis are for the field coil. The field coil in the speaker measured about 600 ohms DC. As you stated earlier the voice connections go to the two of the four screw terminal on the left rear of the chassis. However in my case there are two small coils in the speaker of ultra fine many hundreds of turns of which one is open. Does anyone have a parts speaker out there?
: : Thanks for the info. The 22mF caps you are mentioning. Is that actually m(milli) or u(micro) farad. I belive that in the good old days these were interchangeable terms. If you want me to ohm out the speaker connections, not a problem, I will take a look at it this weekend. I used to restore vintage jukes and they used electro dynamic speakers. Apparently permanent magnets were not avail. so they ran the DC power bus through a coil in the speaker to create a magnetic field. I suspect the speaker for this is identical in operation although I have not looked into too closely yet. Speaking of tubes for this guy. There is a resident set inside but I have no idea of the condition at this time. What would you suspect a set would cost. You have my curiosity up now?

:
: : : Erik,
: : : here is my e mail..
: : : Ps, i hope you have lots of money if you decide to re-tube that thing..

: : :
: : : : Eric, i you have time could you send a drawing of your internal speaker connections? Maybe someone could shed some light.. is this a push-pull setup? seems early..
: : : : The grids are fed from either end of the last audio transformer and the input is center-tapped.
: : : : David

: : :
: : : : : Eric,
: : : : : I believe the 2 pin wires either can be used in the 2 female phone plugs or under the "N" and "P" terminals (which are the same connected by a run of wire.) Both N and P and the phone terms come off the plate of the 71a's..
: : : : : The 2 bare leads i am assuming go to term "G".
: : : : : "A" is antenna..
: : : : : I dont have the original speaker with mine and it's put away right now, but i recall you should be able to get audio from either one of the 71a plates with a ground from an everyday output tx..
: : : : :
: : : : : Those values in the large copper can are unknown to me, but i replaced mine with a (2) 22mf 450 and it works just fine.. I suspect the originals are lower than that, typically 8 or 12..
: : : : : David

: : : :
: : : : :
: : : : : : I have a model 706. I have a schematic which is fairly worthless because the text is not readable. Question. The speaker has four wires, two with pins and two bare. I took the lid off of the radio and on the right rear of the chassis there appears to be two female connections for the pins. On the left rear there is a terminal strip with four screws. I assume that the bare pair of wires go to two of these. Help, which ones! Any info on this radio appreciated. I would like to get in there and rebuild it soon. Also does anyone have the value of the dual capacitor?

The original tubes will be fine; don't worry about replacing them unless proven otherwise.

The 71As run in push-pull, a standard circuit except for the fact that there is no secondary on the output transformer that would normally feed the speaker voice coil. Instead, the speaker is high-impedance, fed directly from the 71A plates. In any "normal" set, the speaker would be isolated by a capacitor, but I don't see any here, and I suspect that cheapo-Crosley left it out. That would put DC through the speaker coils, so you need both of them to balance it out. The old coils can be rewound but it probably won't be any fun. Forget about finding replacements: you're lucky to have a speaker at all (I'm missing one).

Check the pot-metal tuning drive before you invest too much time in this thing. These sets were never intended to last 70 years.

Well, I have unwound the inductor in the speaker driver unit. It appears to be 4010 turns of #40AWG magnet wire. Should be a joy to rewind. Measured the inductance, Its 139mH (milli)and series resistance of 709 ohms, measured at 1kHz.
: The original tubes will be fine; don't worry about replacing them unless proven otherwise.

: The 71As run in push-pull, a standard circuit except for the fact that there is no secondary on the output transformer that would normally feed the speaker voice coil. Instead, the speaker is high-impedance, fed directly from the 71A plates. In any "normal" set, the speaker would be isolated by a capacitor, but I don't see any here, and I suspect that cheapo-Crosley left it out. That would put DC through the speaker coils, so you need both of them to balance it out. The old coils can be rewound but it probably won't be any fun. Forget about finding replacements: you're lucky to have a speaker at all (I'm missing one).

: Check the pot-metal tuning drive before you invest too much time in this thing. These sets were never intended to last 70 years.

Ok, i meant the secondary is CT ground. It is a push pull amplifer. duh... These showboxes should rock when we get them right..

: Eric, i you have time could you send a drawing of your internal speaker connections? Maybe someone could shed some light.. is this a push-pull setup? seems early..
: The grids are fed from either end of the last audio transformer and the input is center-tapped.
: David

: : Eric,
: : I believe the 2 pin wires either can be used in the 2 female phone plugs or under the "N" and "P" terminals (which are the same connected by a run of wire.) Both N and P and the phone terms come off the plate of the 71a's..
: : The 2 bare leads i am assuming go to term "G".
: : "A" is antenna..
: : I dont have the original speaker with mine and it's put away right now, but i recall you should be able to get audio from either one of the 71a plates with a ground from an everyday output tx..
: :
: : Those values in the large copper can are unknown to me, but i replaced mine with a (2) 22mf 450 and it works just fine.. I suspect the originals are lower than that, typically 8 or 12..
: : David

:
: :
: : : I have a model 706. I have a schematic which is fairly worthless because the text is not readable. Question. The speaker has four wires, two with pins and two bare. I took the lid off of the radio and on the right rear of the chassis there appears to be two female connections for the pins. On the left rear there is a terminal strip with four screws. I assume that the bare pair of wires go to two of these. Help, which ones! Any info on this radio appreciated. I would like to get in there and rebuild it soon. Also does anyone have the value of the dual capacitor?

Hi Eric, I've sent the Showbox schematic, might be better than what you've got. Don Black.

: I have a model 706. I have a schematic which is fairly worthless because the text is not readable. Question. The speaker has four wires, two with pins and two bare. I took the lid off of the radio and on the right rear of the chassis there appears to be two female connections for the pins. On the left rear there is a terminal strip with four screws. I assume that the bare pair of wires go to two of these. Help, which ones! Any info on this radio appreciated. I would like to get in there and rebuild it soon. Also does anyone have the value of the dual capacitor?