nom
Thomas,
No wonder you wouldn't tell me where to add resistance. You allready told me. Quoting you
"If all is working well, and the voltages are a bit high with this transformer, then perhaps you can continue to use it. Just add resistance to the B circuit to reduce the voltage appropriately. Be sure to add resistance to the + side of the B circuit (off of pin 8 of the rectifiers) so that you don't affect biasing in the negative side of the circuit"
Now the question is what size and how high wattage. Sound's like ohm's law basic 101 but I need to know the amperage there.
:nom
This is apparently a final addenda to the other string, so I am just adding on this point......
Was away for ‘da weekend…..and am just now seeing what has happened on diff topics…starting with yours.
So, it looks like you might have "THE" excess voltage T-former on hand and also rectifier tubes having ben procured…….whatever they are….. and now want to bring your developed HV voltage down.
Might as well start at the raw B+ source itself and get the set working again and let it load down the supply to actually see what the set is needing current wise , which will fill in the rough initial idea of which manner to proceed .
With the given that the Zenith shop manual said to be expecting about 340VDC raw developed B+..and loaded right at the rectifier tube propers. That would entail about a max of 10 ohms per volt loading.
Sooooo , experimentally at first, insert a 50 ohm (a min of 5 W or 10 W for cooool ) between the B+ derivative source at the rectifier(s) filaments/ cathodes [I don’t know what you finally decided upon ? ] and the input to the speaker field / choke winding.
Then you will be DC voltage monitoring across the power supply's input filter cap at C17 and you then bring up the AC line voltage slowly and see what raw B+ is starting to develop at the input of the field coil and C17 junction , where , we are waiting to see 340 VDC develop at that point.
Now, if you have the AC line voltage already approaching its standard line input voltage value and the 340 has NOT having been reached, then the 50 ohm value will need to be decreased / or shunted to potentially get it down to as low as possibly a ~35 ohm value.
Standing by for feedback at this point…….
73's de Edd
I understand what you've written, so we got a good start.
I was needing info that you just provided. I have 100 ohm 10 Watt resistors, but I'll have to dig deeper to come up with more 50 ohms. The one I used for my candohm 40 ohm would be just right because it was a wirewound adjustable.
My tubes aren't here yet, but I'm expecting them soon. So I'll get the resistors wired in and we'll go from there...THANK YOU...
:
:
:
:
:
:
:
:
:
:
:
:
:This is apparently a final addenda to the other string, so I am just adding on this point......
:
:
:Was away for ‘da weekend…..and am just now seeing what has happened on diff topics…starting with yours.
:
:
:So, it looks like you might have "THE" excess voltage T-former on hand and also rectifier tubes having ben procured…….whatever they are….. and now want to bring your developed HV voltage down.
:
:Might as well start at the raw B+ source itself and get the set working again and let it load down the supply to actually see what the set is needing current wise , which will fill in the rough initial idea of which manner to proceed .
:
:
:With the given that the Zenith shop manual said to be expecting about 340VDC raw developed B+..and loaded right at the rectifier tube propers. That would entail about a max of 10 ohms per volt loading.
:Sooooo , experimentally at first, insert a 50 ohm (a min of 5 W or 10 W for cooool ) between the B+ derivative source at the rectifier(s) filaments/ cathodes [I don’t know what you finally decided upon ? ] and the input to the speaker field / choke winding.
:
:
:Then you will be DC voltage monitoring across the power supply's input filter cap at C17 and you then bring up the AC line voltage slowly and see what raw B+ is starting to develop at the input of the field coil and C17 junction , where , we are waiting to see 340 VDC develop at that point.
:
:Now, if you have the AC line voltage already approaching its standard line input voltage value and the 340 has NOT having been reached, then the 50 ohm value will need to be decreased / or shunted to potentially get it down to as low as possibly a ~35 ohm value.
:
:
:Standing by for feedback at this point…….
:
:
:
:73's de Edd
:
:
:
:
:
:
:
:
:Edd....welcome back...I got my 6.3vac ct transformer today. So I can get that wired in.
:
:I understand what you've written, so we got a good start.
:
:I was needing info that you just provided. I have 100 ohm 10 Watt resistors, but I'll have to dig deeper to come up with more 50 ohms. The one I used for my candohm 40 ohm would be just right because it was a wirewound adjustable.
:
:My tubes aren't here yet, but I'm expecting them soon. So I'll get the resistors wired in and we'll go from there...THANK YOU...
:
::
::
::
::
::
::
::
::
::
::
::
::
::This is apparently a final addenda to the other string, so I am just adding on this point......
::
::
::Was away for ‘da weekend…..and am just now seeing what has happened on diff topics…starting with yours.
::
::
::So, it looks like you might have "THE" excess voltage T-former on hand and also rectifier tubes having ben procured…….whatever they are….. and now want to bring your developed HV voltage down.
::
::Might as well start at the raw B+ source itself and get the set working again and let it load down the supply to actually see what the set is needing current wise , which will fill in the rough initial idea of which manner to proceed .
::
::
::With the given that the Zenith shop manual said to be expecting about 340VDC raw developed B+..and loaded right at the rectifier tube propers. That would entail about a max of 10 ohms per volt loading.
::Sooooo , experimentally at first, insert a 50 ohm (a min of 5 W or 10 W for cooool ) between the B+ derivative source at the rectifier(s) filaments/ cathodes [I don’t know what you finally decided upon ? ] and the input to the speaker field / choke winding.
::
::
::Then you will be DC voltage monitoring across the power supply's input filter cap at C17 and you then bring up the AC line voltage slowly and see what raw B+ is starting to develop at the input of the field coil and C17 junction , where , we are waiting to see 340 VDC develop at that point.
::
::Now, if you have the AC line voltage already approaching its standard line input voltage value and the 340 has NOT having been reached, then the 50 ohm value will need to be decreased / or shunted to potentially get it down to as low as possibly a ~35 ohm value.
::
::
::Standing by for feedback at this point…….
::
::
::
::73's de Edd
::
::
::
::
::
::
::
::
Thanks Tony, but I already thought of that. I'll double my wattage rating also. Hope they'll all fit physically. There's always room for one more component right!!
:Put two of the 100 ohm in parallel and you'll have a 50 ohm unit ;)
:
::Edd....welcome back...I got my 6.3vac ct transformer today. So I can get that wired in.
::
::I understand what you've written, so we got a good start.
::
::I was needing info that you just provided. I have 100 ohm 10 Watt resistors, but I'll have to dig deeper to come up with more 50 ohms. The one I used for my candohm 40 ohm would be just right because it was a wirewound adjustable.
::
::My tubes aren't here yet, but I'm expecting them soon. So I'll get the resistors wired in and we'll go from there...THANK YOU...
::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::This is apparently a final addenda to the other string, so I am just adding on this point......
:::
:::
:::Was away for ‘da weekend…..and am just now seeing what has happened on diff topics…starting with yours.
:::
:::
:::So, it looks like you might have "THE" excess voltage T-former on hand and also rectifier tubes having ben procured…….whatever they are….. and now want to bring your developed HV voltage down.
:::
:::Might as well start at the raw B+ source itself and get the set working again and let it load down the supply to actually see what the set is needing current wise , which will fill in the rough initial idea of which manner to proceed .
:::
:::
:::With the given that the Zenith shop manual said to be expecting about 340VDC raw developed B+..and loaded right at the rectifier tube propers. That would entail about a max of 10 ohms per volt loading.
:::Sooooo , experimentally at first, insert a 50 ohm (a min of 5 W or 10 W for cooool ) between the B+ derivative source at the rectifier(s) filaments/ cathodes [I don’t know what you finally decided upon ? ] and the input to the speaker field / choke winding.
:::
:::
:::Then you will be DC voltage monitoring across the power supply's input filter cap at C17 and you then bring up the AC line voltage slowly and see what raw B+ is starting to develop at the input of the field coil and C17 junction , where , we are waiting to see 340 VDC develop at that point.
:::
:::Now, if you have the AC line voltage already approaching its standard line input voltage value and the 340 has NOT having been reached, then the 50 ohm value will need to be decreased / or shunted to potentially get it down to as low as possibly a ~35 ohm value.
:::
:::
:::Standing by for feedback at this point…….
:::
:::
:::
:::73's de Edd
:::
:::
:::
:::
:::
:::
:::
:::
And if I got to go down to ~35, I can justparallel in one more!!!!
:
::Edd....welcome back...I got my 6.3vac ct transformer today. So I can get that wired in.
::
::I understand what you've written, so we got a good start.
::
::I was needing info that you just provided. I have 100 ohm 10 Watt resistors, but I'll have to dig deeper to come up with more 50 ohms. The one I used for my candohm 40 ohm would be just right because it was a wirewound adjustable.
::
::My tubes aren't here yet, but I'm expecting them soon. So I'll get the resistors wired in and we'll go from there...THANK YOU...
::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::This is apparently a final addenda to the other string, so I am just adding on this point......
:::
:::
:::Was away for ‘da weekend…..and am just now seeing what has happened on diff topics…starting with yours.
:::
:::
:::So, it looks like you might have "THE" excess voltage T-former on hand and also rectifier tubes having ben procured…….whatever they are….. and now want to bring your developed HV voltage down.
:::
:::Might as well start at the raw B+ source itself and get the set working again and let it load down the supply to actually see what the set is needing current wise , which will fill in the rough initial idea of which manner to proceed .
:::
:::
:::With the given that the Zenith shop manual said to be expecting about 340VDC raw developed B+..and loaded right at the rectifier tube propers. That would entail about a max of 10 ohms per volt loading.
:::Sooooo , experimentally at first, insert a 50 ohm (a min of 5 W or 10 W for cooool ) between the B+ derivative source at the rectifier(s) filaments/ cathodes [I don’t know what you finally decided upon ? ] and the input to the speaker field / choke winding.
:::
:::
:::Then you will be DC voltage monitoring across the power supply's input filter cap at C17 and you then bring up the AC line voltage slowly and see what raw B+ is starting to develop at the input of the field coil and C17 junction , where , we are waiting to see 340 VDC develop at that point.
:::
:::Now, if you have the AC line voltage already approaching its standard line input voltage value and the 340 has NOT having been reached, then the 50 ohm value will need to be decreased / or shunted to potentially get it down to as low as possibly a ~35 ohm value.
:::
:::
:::Standing by for feedback at this point…….
:::
:::
:::
:::73's de Edd
:::
:::
:::
:::
:::
:::
:::
:::
::Put two of the 100 ohm in parallel and you'll have a 50 ohm unit ;)
:
:And if I got to go down to ~35, I can just parallel in one more!!!!
::
:::Edd....welcome back...I got my 6.3vac ct transformer today. So I can get that wired in.
:::
:::I understand what you've written, so we got a good start.
:::
:::I was needing info that you just provided. I have 100 ohm 10 Watt resistors, but I'll have to dig deeper to come up with more 50 ohms. The one I used for my candohm 40 ohm would be just right because it was a wirewound adjustable.
:::
:::My tubes aren't here yet, but I'm expecting them soon. So I'll get the resistors wired in and we'll go from there...THANK YOU...
:::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::This is apparently a final addenda to the other string, so I am just adding on this point......
::::
::::
::::Was away for ‘da weekend…..and am just now seeing what has happened on diff topics…starting with yours.
::::
::::
::::So, it looks like you might have "THE" excess voltage T-former on hand and also rectifier tubes having ben procured…….whatever they are….. and now want to bring your developed HV voltage down.
::::
::::Might as well start at the raw B+ source itself and get the set working again and let it load down the supply to actually see what the set is needing current wise , which will fill in the rough initial idea of which manner to proceed .
::::
::::
::::With the given that the Zenith shop manual said to be expecting about 340VDC raw developed B+..and loaded right at the rectifier tube propers. That would entail about a max of 10 ohms per volt loading.
::::Sooooo , experimentally at first, insert a 50 ohm (a min of 5 W or 10 W for cooool ) between the B+ derivative source at the rectifier(s) filaments/ cathodes [I don’t know what you finally decided upon ? ] and the input to the speaker field / choke winding.
::::
::::
::::Then you will be DC voltage monitoring across the power supply's input filter cap at C17 and you then bring up the AC line voltage slowly and see what raw B+ is starting to develop at the input of the field coil and C17 junction , where , we are waiting to see 340 VDC develop at that point.
::::
::::Now, if you have the AC line voltage already approaching its standard line input voltage value and the 340 has NOT having been reached, then the 50 ohm value will need to be decreased / or shunted to potentially get it down to as low as possibly a ~35 ohm value.
::::
::::
::::Standing by for feedback at this point…….
::::
::::
::::
::::73's de Edd
::::
::::
::::
::::
::::
::::
::::
::::
Just curious or perhaps I have missed something but why are you putting the equivalent of a 50 Ohm resistor in series with each lead of the 6-volt transformer to the filament pins of the 6X5?
Radiodoc
************
:I've wired in the 6.3vac transformer and paralleled 2 100 ohm 10 watt resistors twice. Put one set (50 ohms)in between the 6.3vac winding and pin 7 (6X5). Put the other set (50 ohms) in between the other end of the same 6.3vac winding and pin 2 (6X5). I'm waiting on tubes.
:
:
:::Put two of the 100 ohm in parallel and you'll have a 50 ohm unit ;)
::
::And if I got to go down to ~35, I can just parallel in one more!!!!
:::
::::Edd....welcome back...I got my 6.3vac ct transformer today. So I can get that wired in.
::::
::::I understand what you've written, so we got a good start.
::::
::::I was needing info that you just provided. I have 100 ohm 10 Watt resistors, but I'll have to dig deeper to come up with more 50 ohms. The one I used for my candohm 40 ohm would be just right because it was a wirewound adjustable.
::::
::::My tubes aren't here yet, but I'm expecting them soon. So I'll get the resistors wired in and we'll go from there...THANK YOU...
::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::This is apparently a final addenda to the other string, so I am just adding on this point......
:::::
:::::
:::::Was away for ‘da weekend…..and am just now seeing what has happened on diff topics…starting with yours.
:::::
:::::
:::::So, it looks like you might have "THE" excess voltage T-former on hand and also rectifier tubes having ben procured…….whatever they are….. and now want to bring your developed HV voltage down.
:::::
:::::Might as well start at the raw B+ source itself and get the set working again and let it load down the supply to actually see what the set is needing current wise , which will fill in the rough initial idea of which manner to proceed .
:::::
:::::
:::::With the given that the Zenith shop manual said to be expecting about 340VDC raw developed B+..and loaded right at the rectifier tube propers. That would entail about a max of 10 ohms per volt loading.
:::::Sooooo , experimentally at first, insert a 50 ohm (a min of 5 W or 10 W for cooool ) between the B+ derivative source at the rectifier(s) filaments/ cathodes [I don’t know what you finally decided upon ? ] and the input to the speaker field / choke winding.
:::::
:::::
:::::Then you will be DC voltage monitoring across the power supply's input filter cap at C17 and you then bring up the AC line voltage slowly and see what raw B+ is starting to develop at the input of the field coil and C17 junction , where , we are waiting to see 340 VDC develop at that point.
:::::
:::::Now, if you have the AC line voltage already approaching its standard line input voltage value and the 340 has NOT having been reached, then the 50 ohm value will need to be decreased / or shunted to potentially get it down to as low as possibly a ~35 ohm value.
:::::
:::::
:::::Standing by for feedback at this point…….
:::::
:::::
:::::
:::::73's de Edd
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:Nom,
:
:Just curious or perhaps I have missed something but why are you putting the equivalent of a 50 Ohm resistor in series with each lead of the 6-volt transformer to the filament pins of the 6X5?
:
:Radiodoc
:************
:
:
::I've wired in the 6.3vac transformer and paralleled 2 100 ohm 10 watt resistors twice. Put one set (50 ohms)in between the 6.3vac winding and pin 7 (6X5). Put the other set (50 ohms) in between the other end of the same 6.3vac winding and pin 2 (6X5). I'm waiting on tubes.
::
::
::::Put two of the 100 ohm in parallel and you'll have a 50 ohm unit ;)
:::
:::And if I got to go down to ~35, I can just parallel in one more!!!!
::::
:::::Edd....welcome back...I got my 6.3vac ct transformer today. So I can get that wired in.
:::::
:::::I understand what you've written, so we got a good start.
:::::
:::::I was needing info that you just provided. I have 100 ohm 10 Watt resistors, but I'll have to dig deeper to come up with more 50 ohms. The one I used for my candohm 40 ohm would be just right because it was a wirewound adjustable.
:::::
:::::My tubes aren't here yet, but I'm expecting them soon. So I'll get the resistors wired in and we'll go from there...THANK YOU...
:::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::This is apparently a final addenda to the other string, so I am just adding on this point......
::::::
::::::
::::::Was away for ‘da weekend…..and am just now seeing what has happened on diff topics…starting with yours.
::::::
::::::
::::::So, it looks like you might have "THE" excess voltage T-former on hand and also rectifier tubes having ben procured…….whatever they are….. and now want to bring your developed HV voltage down.
::::::
::::::Might as well start at the raw B+ source itself and get the set working again and let it load down the supply to actually see what the set is needing current wise , which will fill in the rough initial idea of which manner to proceed .
::::::
::::::
::::::With the given that the Zenith shop manual said to be expecting about 340VDC raw developed B+..and loaded right at the rectifier tube propers. That would entail about a max of 10 ohms per volt loading.
::::::Sooooo , experimentally at first, insert a 50 ohm (a min of 5 W or 10 W for cooool ) between the B+ derivative source at the rectifier(s) filaments/ cathodes [I don’t know what you finally decided upon ? ] and the input to the speaker field / choke winding.
::::::
::::::
::::::Then you will be DC voltage monitoring across the power supply's input filter cap at C17 and you then bring up the AC line voltage slowly and see what raw B+ is starting to develop at the input of the field coil and C17 junction , where , we are waiting to see 340 VDC develop at that point.
::::::
::::::Now, if you have the AC line voltage already approaching its standard line input voltage value and the 340 has NOT having been reached, then the 50 ohm value will need to be decreased / or shunted to potentially get it down to as low as possibly a ~35 ohm value.
::::::
::::::
::::::Standing by for feedback at this point…….
::::::
::::::
::::::
::::::73's de Edd
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
:My pin7 and pin8 are jumpered together. Does that make sense? I'm intending to put them where they will drop some of my HVvdc.
:
:
::Nom,
::
::Just curious or perhaps I have missed something but why are you putting the equivalent of a 50 Ohm resistor in series with each lead of the 6-volt transformer to the filament pins of the 6X5?
::
::Radiodoc
::************
::
::
:::I've wired in the 6.3vac transformer and paralleled 2 100 ohm 10 watt resistors twice. Put one set (50 ohms)in between the 6.3vac winding and pin 7 (6X5). Put the other set (50 ohms) in between the other end of the same 6.3vac winding and pin 2 (6X5). I'm waiting on tubes.
:::
:::
:::::Put two of the 100 ohm in parallel and you'll have a 50 ohm unit ;)
::::
::::And if I got to go down to ~35, I can just parallel in one more!!!!
:::::
::::::Edd....welcome back...I got my 6.3vac ct transformer today. So I can get that wired in.
::::::
::::::I understand what you've written, so we got a good start.
::::::
::::::I was needing info that you just provided. I have 100 ohm 10 Watt resistors, but I'll have to dig deeper to come up with more 50 ohms. The one I used for my candohm 40 ohm would be just right because it was a wirewound adjustable.
::::::
::::::My tubes aren't here yet, but I'm expecting them soon. So I'll get the resistors wired in and we'll go from there...THANK YOU...
::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::This is apparently a final addenda to the other string, so I am just adding on this point......
:::::::
:::::::
:::::::Was away for ‘da weekend…..and am just now seeing what has happened on diff topics…starting with yours.
:::::::
:::::::
:::::::So, it looks like you might have "THE" excess voltage T-former on hand and also rectifier tubes having ben procured…….whatever they are….. and now want to bring your developed HV voltage down.
:::::::
:::::::Might as well start at the raw B+ source itself and get the set working again and let it load down the supply to actually see what the set is needing current wise , which will fill in the rough initial idea of which manner to proceed .
:::::::
:::::::
:::::::With the given that the Zenith shop manual said to be expecting about 340VDC raw developed B+..and loaded right at the rectifier tube propers. That would entail about a max of 10 ohms per volt loading.
:::::::Sooooo , experimentally at first, insert a 50 ohm (a min of 5 W or 10 W for cooool ) between the B+ derivative source at the rectifier(s) filaments/ cathodes [I don’t know what you finally decided upon ? ] and the input to the speaker field / choke winding.
:::::::
:::::::
:::::::Then you will be DC voltage monitoring across the power supply's input filter cap at C17 and you then bring up the AC line voltage slowly and see what raw B+ is starting to develop at the input of the field coil and C17 junction , where , we are waiting to see 340 VDC develop at that point.
:::::::
:::::::Now, if you have the AC line voltage already approaching its standard line input voltage value and the 340 has NOT having been reached, then the 50 ohm value will need to be decreased / or shunted to potentially get it down to as low as possibly a ~35 ohm value.
:::::::
:::::::
:::::::Standing by for feedback at this point…….
:::::::
:::::::
:::::::
:::::::73's de Edd
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
Je pense que vous avez perdu quelque chose dans la traduction...
0…
Pienso que usted perdió algo en la traducción...
Or, it seems that you will have the coolest 6X5’s possible, when wiring them that way….
Not exactly sure that you zeroed in on the wiring insertion of the resistor(s), as per the resistors initial evaluation position.
From the end aspect of the power supply having better AC and DC decoupling, along with a lower loading impedance, that position would next be the points where the magenta X’s are positioned....AFTER the preliminary findings.
First, get the set operational to capture the specs of the unit operating with a 350 VDC raw DC being present across input filter + and with the negative metering reference being the units chassis ground.
Chassis markup:
73's de Edd
Well, I thought I understood. I'll fix it....nom
:
:
:
:
:
:
:
:
:
:
:
:Je pense que vous avez perdu quelque chose dans la traduction...
:
:0…
:
:Pienso que usted perdió algo en la traducción...
:
:
:
:Or, it seems that you will have the coolest 6X5’s possible, when wiring them that way….
:
:
:
:
:Not exactly sure that you zeroed in on the wiring insertion of the resistor(s), as per the resistors initial evaluation position.
:
:
:From the end aspect of the power supply having better AC and DC decoupling, along with a lower loading impedance, that position would next be the points where the magenta X’s are positioned....AFTER the preliminary findings.
:
:
:First, get the set operational to capture the specs of the unit operating with a 350 VDC raw DC being present across input filter + and with the negative metering reference being the units chassis ground.
:
:
:
:Chassis markup:
:
:
:
:
:
:
:73's de Edd
:
:
:
:
:
:
T.
Hopefully, I see my mistake and I have corrected it. My 6x5's have pin 8 and pin 7 jumpered together at each socket. That's what confuses me. My HVac is wired to pins 3 and 5. One end of the winding on one tube and one on the other. Let's see if I have it right now. I have my 6.3vac off the power transformer wired to pins 2 and 7 paralled to the other 6x5. I have my 50 ohms between pin 8 (which has always been jumpered to 7) and my speaker plug (670 0hms).
My separate transformers secondary is 12.6vac with a 6.3vac center tap. I have a 6.3vac wire daisy chained on pin 7 from tube to tube throughout the radio and also to my 6.3vac pilot lights. The other end of that winding going to ground. I know it looks like the pilot lights are 120vac on the schematic but that is wrong. I determined the voltage to the power lights way back when. Plus in replacing brittle wire I have verified this. That's the way it always has been. I can only guess that my initial power transformer had two 6.3vac windings.
I am concerned about that surge voltage. I watched it go up to over 500 volts when I first put this new power transformer in. My electrolytics, like you say, are only rated at 450. But my finances at this point won't permit me to buy another transformer. I would like a spare power transformer, that would be handy. Maybe later, after determing just exactly what I need.
I plan on measuring current (in series) when my tubes get in.
Thanks...nom
:That was French and then Spanish. Where you see the purple resistor in his schematic is where you should be putting your resistor (between pin 8 and the radio, not between the filament transformer and the filaments....you want to reduce B voltage, not filament voltage).
:
:T.
:I'm glad I posted how I had it wired. After my embarrassment, I'm allowed a chance to get it right.
:
:Hopefully, I see my mistake and I have corrected it. My 6x5's have pin 8 and pin 7 jumpered together at each socket. That's what confuses me. My HVac is wired to pins 3 and 5. One end of the winding on one tube and one on the other. Let's see if I have it right now. I have my 6.3vac off the power transformer wired to pins 2 and 7 paralled to the other 6x5. I have my 50 ohms between pin 8 (which has always been jumpered to 7) and my speaker plug (670 0hms).
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:My separate transformers secondary is 12.6vac with a 6.3vac center tap. I have a 6.3vac wire daisy chained on pin 7 from tube to tube throughout the radio and also to my 6.3vac pilot lights. The other end of that winding going to ground. I know it looks like the pilot lights are 120vac on the schematic but that is wrong. I determined the voltage to the power lights way back when. Plus in replacing brittle wire I have verified this. That's the way it always has been. I can only guess that my initial power transformer had two 6.3vac windings.
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:I am concerned about that surge voltage. I watched it go up to over 500 volts when I first put this new power transformer in. My electrolytics, like you say, are only rated at 450. But my finances at this point won't permit me to buy another transformer. I would like a spare power transformer, that would be handy. Maybe later, after determing just exactly what I need.
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:I plan on measuring current (in series) when my tubes get in.
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:Thanks...nom
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::That was French and then Spanish. Where you see the purple resistor in his schematic is where you should be putting your resistor (between pin 8 and the radio, not between the filament transformer and the filaments....you want to reduce B voltage, not filament voltage).
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::T.
Everything else sounds fine. You can't return the 350 volt transformer?
T.
I'll switch the 6.3vac's. Why does it make a difference?
:The rest of the tubes in the radio should be fed by the main power transformer's 6.3 volt winding. The separate 6.3 volt transformer (12.6 volt with center tap) should go to the 6X5s ONLY.
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:Everything else sounds fine. You can't return the 350 volt transformer?
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:T.
:I haven't tried returning the power transformer where it has been used and all. I guess it wouldn't hurt to ask. I want to get some ma readings and see what this 50 ohms does to my HVdc first.
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:I'll switch the 6.3vac's. Why does it make a difference?
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::The rest of the tubes in the radio should be fed by the main power transformer's 6.3 volt winding. The separate 6.3 volt transformer (12.6 volt with center tap) should go to the 6X5s ONLY.
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::Everything else sounds fine. You can't return the 350 volt transformer?
::
::T.
T.
No. The whole purpose of the second transformer is to keep the filament wiring of the 6X5s separate from the rest of the radio's filament wiring. The 6X5s are prone to heater-to-cathode shorts. If the heater is connected to the chassis (which is B-), fireworks! Now, you could disconnect the main filament winding from the chassis, but most of the other tubes are only designed to have a difference of 100 volts between the cathodes and the heaters. If one of them shorts, and one of the 6X5s shorts, you have the same problem, plus a few extra blown tubes. Zenith originally designed their sets with the 6X5s running off of the same 6.3 volt winding as the rest of the tubes. It saved an extra winding and saved costs. However, the troubles with the 6X5s were too common, and so Zenith eventually gave their radios a separate filament winding for the 6X5s. I have seen a few Zeniths with their original 6X5s in perfect working order, and they work well, but they are prone to shorts, and it's happened rather often to others.
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:T.
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:No. The whole purpose of the second transformer is to keep the filament wiring of the 6X5s separate from the rest of the radio's filament wiring. The 6X5s are prone to heater-to-cathode shorts. If the heater is connected to the chassis (which is B-), fireworks! Now, you could disconnect the main filament winding from the chassis, but most of the other tubes are only designed to have a difference of 100 volts between the cathodes and the heaters. If one of them shorts, and one of the 6X5s shorts, you have the same problem, plus a few extra blown tubes. Zenith originally designed their sets with the 6X5s running off of the same 6.3 volt winding as the rest of the tubes. It saved an extra winding and saved costs. However, the troubles with the 6X5s were too common, and so Zenith eventually gave their radios a separate filament winding for the 6X5s. I have seen a few Zeniths with their original 6X5s in perfect working order, and they work well, but they are prone to shorts, and it's happened rather often to others.
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::T.
:My tubes came in today. They were replacement tubes. 6X5GT's. I didn't like what I saw. I had low voltage off pin 8 (175vdc) and it didn't seem to matter if I jumpered out the 50 ohms or not. Without the speaker plugged in I had way high vdc (over 500). I'm at work now and I really don't know what's going on with it.
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::My tubes came in today. They were replacement tubes. 6X5GT's. I didn't like what I saw. I had low voltage off pin 8 (175vdc) and it didn't seem to matter if I jumpered out the 50 ohms or not. Without the speaker plugged in I had way high vdc (over 500). I'm at work now and I really don't know what's going on with it.
:
:I was very careful with the candohm resistor values. But I will do as you suggested when I get home from work tonight. (10:30 mst) Thanks, I'm prone to mistakes as of late.
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:::My tubes came in today. They were replacement tubes. 6X5GT's. I didn't like what I saw. I had low voltage off pin 8 (175vdc) and it didn't seem to matter if I jumpered out the 50 ohms or not. Without the speaker plugged in I had way high vdc (over 500). I'm at work now and I really don't know what's going on with it.
::
When I took the first 6v6 out my B+ went from 130vdc to 150vdc. When I took the second one out it went up to 270vdc.
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::I was very careful with the candohm resistor values. But I will do as you suggested when I get home from work tonight. (10:30 mst) Thanks, I'm prone to mistakes as of late.
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::::My tubes came in today. They were replacement tubes. 6X5GT's. I didn't like what I saw. I had low voltage off pin 8 (175vdc) and it didn't seem to matter if I jumpered out the 50 ohms or not. Without the speaker plugged in I had way high vdc (over 500). I'm at work now and I really don't know what's going on with it.
:::
:When I took the first 6v6 out my B+ went from 130vdc to 150vdc. When I took the second one out it went up to 270vdc.
::
:::I was very careful with the candohm resistor values. But I will do as you suggested when I get home from work tonight. (10:30 mst) Thanks, I'm prone to mistakes as of late.
My R20 is 7.3 ohms. Points A & C on your schematic are 390vac. When I measure across A & C I get overload on my meter because it only measures up to 600 vrms.
I have minimal audio on BC and it sounds louder on 'push button automatic'. Nothing on SW. My raw B+ is only 142 vdc. When I take both 6v6's out it jumps up to around 320 vdc. The 50 ohm's have very little effect.
I've measured all the resistances on your schematic even replacing a few to get proper resistances. Except r10, I haven't done him yet.
I have a line fuse in that's only 1.5a and it hasn't blown it. I have a 2a fuse on the center tap.
I'm continuing to check an recheck wiring. That's the most logical reason. Thanks for the work you've done on the schematic you've provided me.
Neal
::When it is completely warmed up I have 390vac on pins 3 and 5. I have 180 vdc on pin 8. I have only a 3 volt drop accross the 50 ohms. I checked my resistances on the candohm (open circuit). They were 203 ohms and 39.4 ohms.
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::When I took the first 6v6 out my B+ went from 130vdc to 150vdc. When I took the second one out it went up to 270vdc.
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::::I was very careful with the candohm resistor values. But I will do as you suggested when I get home from work tonight. (10:30 mst) Thanks, I'm prone to mistakes as of late.
:
Anyway, if I plug it in the wall I get 391vac out of the power transformer. And 450vdc with the 50 ohms in circuit. It seems as if both transformers are out of spec.
What info can I get while I'm here, using the variac to keep vac input at 350? It's late, but I know I need to measure the ma in line to my speaker. I'll do that tomorrow.
I'm considering using zener diodes. I have 4 30v 1W zeners. I could drop 160v if necessary.
Neal
:Boy oh boy...this is a doozer. I've spent the last 3 or 4 hours verifying the wiring and I've yet to find a mistake. One blatant difference is my secondary 6.3vac transformer is driving my 6X5's not the power transformer 6.3vac winding and vice versa. I wired it that way on Thomas' suggestion.
:
:My R20 is 7.3 ohms. Points A & C on your schematic are 390vac. When I measure across A & C I get overload on my meter because it only measures up to 600 vrms.
:
:I have minimal audio on BC and it sounds louder on 'push button automatic'. Nothing on SW. My raw B+ is only 142 vdc. When I take both 6v6's out it jumps up to around 320 vdc. The 50 ohm's have very little effect.
:
:I've measured all the resistances on your schematic even replacing a few to get proper resistances. Except r10, I haven't done him yet.
:
:I have a line fuse in that's only 1.5a and it hasn't blown it. I have a 2a fuse on the center tap.
:
:I'm continuing to check an recheck wiring. That's the most logical reason. Thanks for the work you've done on the schematic you've provided me.
:Neal
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:::When it is completely warmed up I have 390vac on pins 3 and 5. I have 180 vdc on pin 8. I have only a 3 volt drop accross the 50 ohms. I checked my resistances on the candohm (open circuit). They were 203 ohms and 39.4 ohms.
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:::When I took the first 6v6 out my B+ went from 130vdc to 150vdc. When I took the second one out it went up to 270vdc.
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:::::I was very careful with the candohm resistor values. But I will do as you suggested when I get home from work tonight. (10:30 mst) Thanks, I'm prone to mistakes as of late.
::
:We've made some progress. I swithed 6.3vac sources back to where the power tranformer source is driving the 6x5's. My secondary transformer isn't putting out 6.3vac center tap. I don't know if using it on the 6x5's fried it or what. I only get 5.4vac under load outside windings. (should be 12.6)
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:Anyway, if I plug it in the wall I get 391vac out of the power transformer. And 450vdc with the 50 ohms in circuit. It seems as if both transformers are out of spec.
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:What info can I get while I'm here, using the variac to keep vac input at 350? It's late, but I know I need to measure the ma in line to my speaker. I'll do that tomorrow.
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:I'm considering using zener diodes. I have 4 30v 1W zeners. I could drop 160v if necessary.
:Neal
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::Boy oh boy...this is a doozer. I've spent the last 3 or 4 hours verifying the wiring and I've yet to find a mistake. One blatant difference is my secondary 6.3vac transformer is driving my 6X5's not the power transformer 6.3vac winding and vice versa. I wired it that way on Thomas' suggestion.
::
::My R20 is 7.3 ohms. Points A & C on your schematic are 390vac. When I measure across A & C I get overload on my meter because it only measures up to 600 vrms.
::
::I have minimal audio on BC and it sounds louder on 'push button automatic'. Nothing on SW. My raw B+ is only 142 vdc. When I take both 6v6's out it jumps up to around 320 vdc. The 50 ohm's have very little effect.
::
::I've measured all the resistances on your schematic even replacing a few to get proper resistances. Except r10, I haven't done him yet.
::
::I have a line fuse in that's only 1.5a and it hasn't blown it. I have a 2a fuse on the center tap.
::
::I'm continuing to check an recheck wiring. That's the most logical reason. Thanks for the work you've done on the schematic you've provided me.
::Neal
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::::When it is completely warmed up I have 390vac on pins 3 and 5. I have 180 vdc on pin 8. I have only a 3 volt drop accross the 50 ohms. I checked my resistances on the candohm (open circuit). They were 203 ohms and 39.4 ohms.
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::::When I took the first 6v6 out my B+ went from 130vdc to 150vdc. When I took the second one out it went up to 270vdc.
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::::::I was very careful with the candohm resistor values. But I will do as you suggested when I get home from work tonight. (10:30 mst) Thanks, I'm prone to mistakes as of late.
:::
T.
It's good to hear from you again. In answer to your question: It WAS 2a.
In troubleshooting the problem of not high enough dc output on the 6x5's, I switched 6.3vac supplies. Alakazam my voltage came right up. I checked the output of the 12.6vac ct at the outside of the winding and it was only 7 vdc. 3.5 at the ct. So it looks to me like both transformers were bad and 3.5 on the 6x5's was why the voltage was only half of what it should be.
Having 391 volts on the output of the power transformer convinced me that eventhough it was new...it was bad.
Using the variac, I dropped the voltage output of the power transformer down until I had the desired output on the 6X5's. ~350vdc. My vac input voltage was 300, and my line voltage was 94. I measure the ma's and found them to be 90ma.
So I have ordered a new 300-0-300 123ma power transformer. I'm sending the 350 back and they are going to check it for a manufacturer's defect. The little one was toast too. So I got a new one of them coming with it. Rated at 4 amps.
Right now I am back to tracking down my loss of sw. I've got the signal path down on paper. It's just a matter of checking it from point to point.
:How many amps is your 12.6 V CT transformer rated for? If it isn't capable of driving two 6X5s, then it doesn't have enough power. It should be rated for at least 1.5 amperes.
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:T.
Gosh it was good to know you were still out there in cyberspace....Neal
Neal
:Hi Thomas,
:
:It's good to hear from you again. In answer to your question: It WAS 2a.
:
:In troubleshooting the problem of not high enough dc output on the 6x5's, I switched 6.3vac supplies. Alakazam my voltage came right up. I checked the output of the 12.6vac ct at the outside of the winding and it was only 7 vdc. 3.5 at the ct. So it looks to me like both transformers were bad and 3.5 on the 6x5's was why the voltage was only half of what it should be.
:
:Having 391 volts on the output of the power transformer convinced me that eventhough it was new...it was bad.
:
:Using the variac, I dropped the voltage output of the power transformer down until I had the desired output on the 6X5's. ~350vdc. My vac input voltage was 300, and my line voltage was 94. I measure the ma's and found them to be 90ma.
:
:So I have ordered a new 300-0-300 123ma power transformer. I'm sending the 350 back and they are going to check it for a manufacturer's defect. The little one was toast too. So I got a new one of them coming with it. Rated at 4 amps.
:
:Right now I am back to tracking down my loss of sw. I've got the signal path down on paper. It's just a matter of checking it from point to point.
:
::How many amps is your 12.6 V CT transformer rated for? If it isn't capable of driving two 6X5s, then it doesn't have enough power. It should be rated for at least 1.5 amperes.
::
::T.
:
:Gosh it was good to know you were still out there in cyberspace....Neal
I want to thank you for your help on my set. My transformers came in and it's all wired up. I've re aligned it and it's off the bench. My voltages still are a little high, but it doesn't surge at startup over 450vdc. My BC is superb, both volume and clarity. My SW is spectacular. I've put it back in the console for now. My next set is going to be a 7S657R. For right now, I'll be working on the console of the 7S682. I'll need some help on the best way to go about refurbishing veneer. Thanks again...Neal
:Hello....Soon I'll be wiring in a couple of transformers again. This time I'm going to fuse the small one also. Do you still think it's better to use the 12.6vac ct for the 6X5's? And the power transformer 12.6vac ct for the rest of the radio?s
:Neal
:
::Hi Thomas,
::
::It's good to hear from you again. In answer to your question: It WAS 2a.
::
::In troubleshooting the problem of not high enough dc output on the 6x5's, I switched 6.3vac supplies. Alakazam my voltage came right up. I checked the output of the 12.6vac ct at the outside of the winding and it was only 7 vdc. 3.5 at the ct. So it looks to me like both transformers were bad and 3.5 on the 6x5's was why the voltage was only half of what it should be.
::
::Having 391 volts on the output of the power transformer convinced me that eventhough it was new...it was bad.
::
::Using the variac, I dropped the voltage output of the power transformer down until I had the desired output on the 6X5's. ~350vdc. My vac input voltage was 300, and my line voltage was 94. I measure the ma's and found them to be 90ma.
::
::So I have ordered a new 300-0-300 123ma power transformer. I'm sending the 350 back and they are going to check it for a manufacturer's defect. The little one was toast too. So I got a new one of them coming with it. Rated at 4 amps.
::
::Right now I am back to tracking down my loss of sw. I've got the signal path down on paper. It's just a matter of checking it from point to point.
::
:::How many amps is your 12.6 V CT transformer rated for? If it isn't capable of driving two 6X5s, then it doesn't have enough power. It should be rated for at least 1.5 amperes.
:::
:::T.
::
::Gosh it was good to know you were still out there in cyberspace....Neal
A resistor doesn't solve your initial voltage surge, however. Resistors only drop voltage when there is a load on them. If the rectifiers heat up before the other tubes heat up, which is when you're seeing your surge, the resistors you have added will be unloaded, and your electrolytics will still see 500 volts. You could use several 13 volt zener diodes wired in series, which would very definitely drop the voltage, no matter what the condition. I don't really like that approach, though. I don't trust solid state devices that much....especially when dealing with high voltages. What a zener diode will do, however, is pass voltage in excess of what it is rated for. Theoretically, if you wanted to drop 13 volts, you could put in a 13 volt zener, which would pass all voltage in excess of 13. At 500 volts, you'd see 487, and whatever the voltage settled at after the radio warmed up, you'd see 13 volts less than that after the zener. Using multiple 13 volt zener diodes (usually available at Radio Shack....I believe) would give you the multiple of 13 as a voltage drop.
The best approach, in my opinion, would be to either increase the ratings of the electrolytics (if you can find 550 or 600 volt electrolytics....not likely) and then use resistors to drop the voltage to the appropriate level under load (radio warmed up), or to obtain a transformer that would give you proper voltages without modifications, or at least no surges over 450 volts.....load voltages being adjusted with resistors.
T.
:You can put your ammeter in series with the B+ connection to see how much amperage is flowing. Take the voltage you wish to drop and divide it by the amperage you see (probably mA.). That will give you the ohms you need. The resistor should be a 10 watt resistor. You probably don't need more than that, and you might be able to use a 5 watt unit.
:
:A resistor doesn't solve your initial voltage surge, however. Resistors only drop voltage when there is a load on them. If the rectifiers heat up before the other tubes heat up, which is when you're seeing your surge, the resistors you have added will be unloaded, and your electrolytics will still see 500 volts. You could use several 13 volt zener diodes wired in series, which would very definitely drop the voltage, no matter what the condition. I don't really like that approach, though. I don't trust solid state devices that much....especially when dealing with high voltages. What a zener diode will do, however, is pass voltage in excess of what it is rated for. Theoretically, if you wanted to drop 13 volts, you could put in a 13 volt zener, which would pass all voltage in excess of 13. At 500 volts, you'd see 487, and whatever the voltage settled at after the radio warmed up, you'd see 13 volts less than that after the zener. Using multiple 13 volt zener diodes (usually available at Radio Shack....I believe) would give you the multiple of 13 as a voltage drop.
:
:The best approach, in my opinion, would be to either increase the ratings of the electrolytics (if you can find 550 or 600 volt electrolytics....not likely) and then use resistors to drop the voltage to the appropriate level under load (radio warmed up), or to obtain a transformer that would give you proper voltages without modifications, or at least no surges over 450 volts.....load voltages being adjusted with resistors.
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:T.
T.
:If you wish, try the zeners. Wire them with the line facing the rectifier (I think). Their cathodes should face the rectifier cathodes, since a zener works when it is reverse biased. If you don't notice any voltage drop across the zener(s), then you have them in backwards.
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:T.
It ate those zeners up like they were nothin'.
Neal
:I'm more familiar with zeners than tubes. I'm still waiting on tubes though before I can try anything.
Thanks for the wiring checkout....Neal
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::If you wish, try the zeners. Wire them with the line facing the rectifier (I think). Their cathodes should face the rectifier cathodes, since a zener works when it is reverse biased. If you don't notice any voltage drop across the zener(s), then you have them in backwards.
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::T.