Couple of Questions
4/1/2008 10:01:48 AMMike C(61012:0)
Was working on an old Sparton 141 that would make not a sound. I tested the tubes and found that the 6AV6 was bad but others tested fine. Found a NIB 6AV6 and put it in radio. Still nothing. Checked NIB 6AV6 on tube tester and it showed excellent. Hmmmmmm!Took 6AV6 out of other working radio on bench and the old Sparton came to life!!!Hmmmmmm???? Is this unusual or not???? I rechecked the first NIB 6AV6 several times and it showed no shorts and tested excellent but would not work in either radio.
The other question is on an Aria (Allied Purchase) model 572. The parts list shows R1 and R14 as 100 M Ohm, but both display as 1 M ohm....brown,black,yellow.
Which is right??? I want to replace both as they both look pretty sad and R1 is pretty tough to get at.
The other question is on an Aria (Allied Purchase) model 572. The parts list shows R1 and R14 as 100 M Ohm, but both display as 1 M ohm....brown,black,yellow.
Which is right??? I want to replace both as they both look pretty sad and R1 is pretty tough to get at.
4/1/2008 11:42:11 AMBill G.(61014:61012)
:Was working on an old Sparton 141 that would make not a sound. I tested the tubes and found that the 6AV6 was bad but others tested fine. Found a NIB 6AV6 and put it in radio. Still nothing. Checked NIB 6AV6 on tube tester and it showed excellent. Hmmmmmm!Took 6AV6 out of other working radio on bench and the old Sparton came to life!!!Hmmmmmm???? Is this unusual or not???? I rechecked the first NIB 6AV6 several times and it showed no shorts and tested excellent but would not work in either radio.
: The other question is on an Aria (Allied Purchase) model 572. The parts list shows R1 and R14 as 100 M Ohm, but both display as 1 M ohm....brown,black,yellow.
:Which is right??? I want to replace both as they both look pretty sad and R1 is pretty tough to get at.
: The other question is on an Aria (Allied Purchase) model 572. The parts list shows R1 and R14 as 100 M Ohm, but both display as 1 M ohm....brown,black,yellow.
:Which is right??? I want to replace both as they both look pretty sad and R1 is pretty tough to get at.
Hi Mike,
My suspicion on your 6AV6 is that it has a detached plate. This is quite rare, so tube testers don't test for it. They typically test using the grid as a plate, and check the cathode to grid current on the triode section. If you are curious, look inside the tube and see if a detecment can be seen. With the NIB 6AV6 in the socket, you may get a plate voltage that is too high, too.
In old schematics, 'M' means thousand, or K in today's terminology. As you suspect your R1 and R14 are shot. Even their color codes indicate that they should be 100K, not 1 Meg.
Best Regards,
Bill Grimm
4/1/2008 11:56:29 AMEdd(61015:61012)
Looks like R1 is an isolation / dropping resistor tailoring the needs of the AVC feed to the RF amp stage of the set .
While your R-uh-14 is the companion to R13 along with C24 in supplying B+ to the 6SQ7 plate circuitry along with some tonal coloration by partial bypassing of some high AF frequencies.
Both values are one hundred thousand ohms….no ambiguity there …eh ?
No ideas on the “Great / Selective 6AV6 Fiasco” since the tube doesn’t involve the connections of a tube element to two connections , such that a tube pin wiring connection might be made on one set and not on another. You might further investigate by taking a .01---.1 ufd paper cap and take its long leads and position them such that the injection of “hot” 6.3 VAC from its filament tube pin connection is injected into the 1st grid of the 6AV6 and confirm gain / amplification by a louuuud hummmmm.
If no audio then, inter connect the cap temporarily with test / clip leads and hold down the tube with a thumb pressed into the top of it and whack the side of the tube with a wooden dowel to check for loose internal spot welds, in which case the tube might emit a burst of audio / static during that time element of intermittent contact.
Then, according to the triodes condition, that would narrow it down to the possibility of solely the diode sections being involved.
73's de Edd
4/1/2008 4:01:33 PMMike C(61023:61015)
:
:
:
:
:
:
:
:
:
:
:
:Looks like R1 is an isolation / dropping resistor tailoring the needs of the AVC feed to the RF amp stage of the set .
:
:
:While your R-uh-14 is the companion to R13 along with C24 in supplying B+ to the 6SQ7 plate circuitry along with some tonal coloration by partial bypassing of some high AF frequencies.
:
:
:Both values are one hundred thousand ohms….no ambiguity there …eh ?
:
:
:
:No ideas on the “Great / Selective 6AV6 Fiasco” since the tube doesn’t involve the connections of a tube element to two connections , such that a tube pin wiring connection might be made on one set and not on another. You might further investigate by taking a .01---.1 ufd paper cap and take its long leads and position them such that the injection of “hot” 6.3 VAC from its filament tube pin connection is injected into the 1st grid of the 6AV6 and confirm gain / amplification by a louuuud hummmmm.
:
:If no audio then, inter connect the cap temporarily with test / clip leads and hold down the tube with a thumb pressed into the top of it and whack the side of the tube with a wooden dowel to check for loose internal spot welds, in which case the tube might emit a burst of audio / static during that time element of intermittent contact.
:
:Then, according to the triodes condition, that would narrow it down to the possibility of solely the diode sections being involved.
:
:
:73's de Edd
:
:You guys really know how to scare a novice! I need more tools and more education. I read everything I get my hands on, and I can't afford another divorce so the tools will have to wait a little longer. I keep several old Spartons around and actually have one with a transformer that starts to smoke. Is it possible for a tube to cause that or just a transformer that is bad or going bad?
:
:
:
:
:
:
:
:
:
:
:
:Looks like R1 is an isolation / dropping resistor tailoring the needs of the AVC feed to the RF amp stage of the set .
:
:
:While your R-uh-14 is the companion to R13 along with C24 in supplying B+ to the 6SQ7 plate circuitry along with some tonal coloration by partial bypassing of some high AF frequencies.
:
:
:Both values are one hundred thousand ohms….no ambiguity there …eh ?
:
:
:
:No ideas on the “Great / Selective 6AV6 Fiasco” since the tube doesn’t involve the connections of a tube element to two connections , such that a tube pin wiring connection might be made on one set and not on another. You might further investigate by taking a .01---.1 ufd paper cap and take its long leads and position them such that the injection of “hot” 6.3 VAC from its filament tube pin connection is injected into the 1st grid of the 6AV6 and confirm gain / amplification by a louuuud hummmmm.
:
:If no audio then, inter connect the cap temporarily with test / clip leads and hold down the tube with a thumb pressed into the top of it and whack the side of the tube with a wooden dowel to check for loose internal spot welds, in which case the tube might emit a burst of audio / static during that time element of intermittent contact.
:
:Then, according to the triodes condition, that would narrow it down to the possibility of solely the diode sections being involved.
:
:
:73's de Edd
:
:You guys really know how to scare a novice! I need more tools and more education. I read everything I get my hands on, and I can't afford another divorce so the tools will have to wait a little longer. I keep several old Spartons around and actually have one with a transformer that starts to smoke. Is it possible for a tube to cause that or just a transformer that is bad or going bad?
:
:
:
:
:
:
4/1/2008 5:37:03 PMEdd(61028:61023)
::
::
::
::
::
::
::
::
::
::
::
::Looks like R1 is an isolation / dropping resistor tailoring the needs of the AVC feed to the RF amp stage of the set .
::
::
::While your R-uh-14 is the companion to R13 along with C24 in supplying B+ to the 6SQ7 plate circuitry along with some tonal coloration by partial bypassing of some high AF frequencies.
::
::
::Both values are one hundred thousand ohms….no ambiguity there …eh ?
::
::
::
::No ideas on the “Great / Selective 6AV6 Fiasco” since the tube doesn’t involve the connections of a tube element to two connections , such that a tube pin wiring connection might be made on one set and not on another. You might further investigate by taking a .01---.1 ufd paper cap and take its long leads and position them such that the injection of “hot” 6.3 VAC from its filament tube pin connection is injected into the 1st grid of the 6AV6 and confirm gain / amplification by a louuuud hummmmm.
::
::If no audio then, inter connect the cap temporarily with test / clip leads and hold down the tube with a thumb pressed into the top of it and whack the side of the tube with a wooden dowel to check for loose internal spot welds, in which case the tube might emit a burst of audio / static during that time element of intermittent contact.
::
::Then, according to the triodes condition, that would narrow it down to the possibility of solely the diode sections being involved.
::
::
::73's de Edd
::
::You guys really know how to scare a novice! I need more tools and more education. I read everything I get my hands on, and I can't afford another divorce so the tools will have to wait a little longer. I keep several old Spartons around and actually have one with a transformer that starts to smoke. Is it possible for a tube to cause that or just a transformer that is bad or going bad?
::
:
:::
::
It may have already gone bad or is just now marginal…at the least, you are going to still be smelling the ole “tinky” odors emanating from from its housing for a year or so.
To confirm, pull all of the sets tubes and plug in to warm up the PT-former, where you would have only its primary having power and stand by with cord in hand to yank and wait for progressively more warm up time and if it makes 10 minutes…check the transformers case temperature with a hand and lock into memory storage and then see how much longer with out any increase in temperature. ( OR ,moke…’moke…I ‘MELLS MOKE ! ).
If I then makes a period of time, you can then place in the tubes, excluding the power rectifier tube, to subject it to progressively more loading from just the filaments being in circuit with further timely temp samplings being done..
Theeeennnn the real test would be with the rectifier tube inserted, but that might be the point where the trouble onsets, if there are electrolytic capacitors in the unit exhibiting aggressively high leakage currents through them.
Any failure prior to this stage would suggest that the strain on the power transformer in the past was just too much for it.
::
::
::
::
::
::
::
::
::
::
::Looks like R1 is an isolation / dropping resistor tailoring the needs of the AVC feed to the RF amp stage of the set .
::
::
::While your R-uh-14 is the companion to R13 along with C24 in supplying B+ to the 6SQ7 plate circuitry along with some tonal coloration by partial bypassing of some high AF frequencies.
::
::
::Both values are one hundred thousand ohms….no ambiguity there …eh ?
::
::
::
::No ideas on the “Great / Selective 6AV6 Fiasco” since the tube doesn’t involve the connections of a tube element to two connections , such that a tube pin wiring connection might be made on one set and not on another. You might further investigate by taking a .01---.1 ufd paper cap and take its long leads and position them such that the injection of “hot” 6.3 VAC from its filament tube pin connection is injected into the 1st grid of the 6AV6 and confirm gain / amplification by a louuuud hummmmm.
::
::If no audio then, inter connect the cap temporarily with test / clip leads and hold down the tube with a thumb pressed into the top of it and whack the side of the tube with a wooden dowel to check for loose internal spot welds, in which case the tube might emit a burst of audio / static during that time element of intermittent contact.
::
::Then, according to the triodes condition, that would narrow it down to the possibility of solely the diode sections being involved.
::
::
::73's de Edd
::
::You guys really know how to scare a novice! I need more tools and more education. I read everything I get my hands on, and I can't afford another divorce so the tools will have to wait a little longer. I keep several old Spartons around and actually have one with a transformer that starts to smoke. Is it possible for a tube to cause that or just a transformer that is bad or going bad?
::
:
:::
::
It may have already gone bad or is just now marginal…at the least, you are going to still be smelling the ole “tinky” odors emanating from from its housing for a year or so.
To confirm, pull all of the sets tubes and plug in to warm up the PT-former, where you would have only its primary having power and stand by with cord in hand to yank and wait for progressively more warm up time and if it makes 10 minutes…check the transformers case temperature with a hand and lock into memory storage and then see how much longer with out any increase in temperature. ( OR ,moke…’moke…I ‘MELLS MOKE ! ).
If I then makes a period of time, you can then place in the tubes, excluding the power rectifier tube, to subject it to progressively more loading from just the filaments being in circuit with further timely temp samplings being done..
Theeeennnn the real test would be with the rectifier tube inserted, but that might be the point where the trouble onsets, if there are electrolytic capacitors in the unit exhibiting aggressively high leakage currents through them.
Any failure prior to this stage would suggest that the strain on the power transformer in the past was just too much for it.
73's de Edd
4/2/2008 8:37:25 PMMike C(61084:61028)
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::Looks like R1 is an isolation / dropping resistor tailoring the needs of the AVC feed to the RF amp stage of the set .
:::
:::
:::While your R-uh-14 is the companion to R13 along with C24 in supplying B+ to the 6SQ7 plate circuitry along with some tonal coloration by partial bypassing of some high AF frequencies.
:::
:::
:::Both values are one hundred thousand ohms….no ambiguity there …eh ?
:::
:::
:::
:::No ideas on the “Great / Selective 6AV6 Fiasco” since the tube doesn’t involve the connections of a tube element to two connections , such that a tube pin wiring connection might be made on one set and not on another. You might further investigate by taking a .01---.1 ufd paper cap and take its long leads and position them such that the injection of “hot” 6.3 VAC from its filament tube pin connection is injected into the 1st grid of the 6AV6 and confirm gain / amplification by a louuuud hummmmm.
:::
:::If no audio then, inter connect the cap temporarily with test / clip leads and hold down the tube with a thumb pressed into the top of it and whack the side of the tube with a wooden dowel to check for loose internal spot welds, in which case the tube might emit a burst of audio / static during that time element of intermittent contact.
:::
:::Then, according to the triodes condition, that would narrow it down to the possibility of solely the diode sections being involved.
:::
:::
:::73's de Edd
:::
:::You guys really know how to scare a novice! I need more tools and more education. I read everything I get my hands on, and I can't afford another divorce so the tools will have to wait a little longer. I keep several old Spartons around and actually have one with a transformer that starts to smoke. Is it possible for a tube to cause that or just a transformer that is bad or going bad?
:::
::
::::
:::
:
:
:
:
:
:
:
:
:
:
:
:It may have already gone bad or is just now marginal…at the least, you are going to still be smelling the ole “tinky” odors emanating from from its housing for a year or so.
:
:
:To confirm, pull all of the sets tubes and plug in to warm up the PT-former, where you would have only its primary having power and stand by with cord in hand to yank and wait for progressively more warm up time and if it makes 10 minutes…check the transformers case temperature with a hand and lock into memory storage and then see how much longer with out any increase in temperature. ( OR ,moke…’moke…I ‘MELLS MOKE ! ).
:
: If I then makes a period of time, you can then place in the tubes, excluding the power rectifier tube, to subject it to progressively more loading from just the filaments being in circuit with further timely temp samplings being done..
:
:
:Theeeennnn the real test would be with the rectifier tube inserted, but that might be the point where the trouble onsets, if there are electrolytic capacitors in the unit exhibiting aggressively high leakage currents through them.
:
:
:Any failure prior to this stage would suggest that the strain on the power transformer in the past was just too much for it.
:
:
:
:73's de Edd
:
:
:
:
:
:
:
:
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::Looks like R1 is an isolation / dropping resistor tailoring the needs of the AVC feed to the RF amp stage of the set .
:::
:::
:::While your R-uh-14 is the companion to R13 along with C24 in supplying B+ to the 6SQ7 plate circuitry along with some tonal coloration by partial bypassing of some high AF frequencies.
:::
:::
:::Both values are one hundred thousand ohms….no ambiguity there …eh ?
:::
:::
:::
:::No ideas on the “Great / Selective 6AV6 Fiasco” since the tube doesn’t involve the connections of a tube element to two connections , such that a tube pin wiring connection might be made on one set and not on another. You might further investigate by taking a .01---.1 ufd paper cap and take its long leads and position them such that the injection of “hot” 6.3 VAC from its filament tube pin connection is injected into the 1st grid of the 6AV6 and confirm gain / amplification by a louuuud hummmmm.
:::
:::If no audio then, inter connect the cap temporarily with test / clip leads and hold down the tube with a thumb pressed into the top of it and whack the side of the tube with a wooden dowel to check for loose internal spot welds, in which case the tube might emit a burst of audio / static during that time element of intermittent contact.
:::
:::Then, according to the triodes condition, that would narrow it down to the possibility of solely the diode sections being involved.
:::
:::
:::73's de Edd
:::
:::You guys really know how to scare a novice! I need more tools and more education. I read everything I get my hands on, and I can't afford another divorce so the tools will have to wait a little longer. I keep several old Spartons around and actually have one with a transformer that starts to smoke. Is it possible for a tube to cause that or just a transformer that is bad or going bad?
:::
::
::::
:::
:
:
:
:
:
:
:
:
:
:
:
:It may have already gone bad or is just now marginal…at the least, you are going to still be smelling the ole “tinky” odors emanating from from its housing for a year or so.
:
:
:To confirm, pull all of the sets tubes and plug in to warm up the PT-former, where you would have only its primary having power and stand by with cord in hand to yank and wait for progressively more warm up time and if it makes 10 minutes…check the transformers case temperature with a hand and lock into memory storage and then see how much longer with out any increase in temperature. ( OR ,moke…’moke…I ‘MELLS MOKE ! ).
:
: If I then makes a period of time, you can then place in the tubes, excluding the power rectifier tube, to subject it to progressively more loading from just the filaments being in circuit with further timely temp samplings being done..
:
:
:Theeeennnn the real test would be with the rectifier tube inserted, but that might be the point where the trouble onsets, if there are electrolytic capacitors in the unit exhibiting aggressively high leakage currents through them.
:
:
:Any failure prior to this stage would suggest that the strain on the power transformer in the past was just too much for it.
:
:
:
:73's de Edd
:
:
:
:
:
:
:
:
Welllllll, I got all the way to the 5Y3 tube before smelling smoke and seeing a dab before I yanked the the plug. I didn't replace any of the caps and think it probably isn't worth my time doing so. Think this one will become a "parts" radio.