:
I will check the chassis and see if this cap you are referring to perhaps shorted when the electrolytic did. All of the coupling caps were replaced in the past.
The other possibility is a silver mica that has gone bad. No foolproof way to test, but can produce thunder and crackling. If I have to dismantle an IF can to get at it, I routinely clip out the old one and discard it. In goes a recently manufactured silver mica and I'm done with it.
::Did you put in the .02 600mfd coupling cap to the grid of the output tube from the plate of the tube before it?
::
:I will check the chassis and see if this cap you are referring to perhaps shorted when the electrolytic did. All of the coupling caps were replaced in the past.
:
:
:The other possibility is a silver mica that has gone bad. No foolproof way to test, but can produce thunder and crackling. If I have to dismantle an IF can to get at it, I routinely clip out the old one and discard it. In goes a recently manufactured silver mica and I'm done with it.
:
:::Did you put in the .02 600mfd coupling cap to the grid of the output tube from the plate of the tube before it?
:::
::I will check the chassis and see if this cap you are referring to perhaps shorted when the electrolytic did. All of the coupling caps were replaced in the past.
::
:
:
Hi All,
Zeniths of this vintage are not susceptable to Silver Mica.
The problem could be in an IF, though, such as an intermittant connection.
All the best,
Bill
Looks like a good ole' case of . . . . . Divide and Conquer !. . . . . analytical troubleshooting (Now . . . THIMK . . . about identifying that pin(s) 3 or 5, since you are viewing the tube from the TOPSIDE ! ) |
::
::When the electrolytic failed it probably took down a resistor or two. Measure the voltage as it is divided and you will most likely find an open or arcing or value way up resistor. You should have replaced all the electrolytics when one became unusable.
::
::The other possibility is a silver mica that has gone bad. No foolproof way to test, but can produce thunder and crackling. If I have to dismantle an IF can to get at it, I routinely clip out the old one and discard it. In goes a recently manufactured silver mica and I'm done with it.
::
::::Did you put in the .02 600mfd coupling cap to the grid of the output tube from the plate of the tube before it?
::::
:::I will check the chassis and see if this cap you are referring to perhaps shorted when the electrolytic did. All of the coupling caps were replaced in the past.
:::
::
:Hi All,
: Zeniths of this vintage are not susceptable to Silver Mica.
: The problem could be in an IF, though, such as an intermittant connection.
:
:All the best,
:
:Bill
:
:
:
: : : :  : : : : : : : :Sir Dave . . . in Center .Tap . . . . : : : :Looks like a good ole' case of . . . . . Divide and Conquer !. . . . . analytical troubleshooting : : :Specifically, one wants to see if the point of origin is in the audio or the frontal RF section. : : :Initially . . . . hopefully you have it occuring FREQUENTLY enough to be able to confirm it rapidly with multiple evaluative testing probes . : : :(Those units when it only occurs every other-other Thursday . . or occasionally Wednesdays, with the wind out of the NNE, and above 72 . . .but less than 80 degrees, and a blue Ford pickup rumbles down the street . . .. intermittents are real BEARS ! ) : : :Initially if you were to merely bring the volume control to its MINIMUM position, and then listening for a period of time, should confirm its origin as being in the AF output stage or erratic power supply related. . . . considering its presence in that no volume position. : : :Now,that would be nonconfirming of the 1st AF stage, so in order to evaluate it and the detector stage try this: : : :It will be necessary to short out the detector plate of the 6H6 tube, and that can be done by not even pulling the chassis, if you will take but a single strand of ~2-3 in length from the fine copper wire in AC line cord wire and unplug the 6H6 and slip one end down into either pin #3 or 5 and replug in the tube. : : (Now . . . THIMK . . . about identifying that pin(s) 3 or 5, since you are viewing the tube from the TOPSIDE ! ) : : :That then lets you short the other end of the wire to ground and then you can turn up the volume to normal . . or higher level . . .and don't expect stations . . .but DO listen for your burst of interferences presence. : : :If you have then deemed that the noise is no longer present, then your Detector-1st audio-AF output stages must not be the origin areas. : : :That is making the need of the removal of the short necessary to then move forward in the signal stream to the I.F. amplifier, that will be easy with that 1st grid connection being accessible at the grid cap at the top of the 6K7 tube . . . . . so you short that 1st grid cap to ground and then have the volume up and listen for the still presence of the inteference. : : :If all is quiet, then there is the need to remove that shorting out and move forward to the 6A8 mixer stage where you would do the same thing with the G4 grid cap atop that tube and perk up your ears again.. : : :That past procedure should have sequentially isolated each stage to give you some clue as to the point of origin of your inteference within your set. . . . CONSIDERING . . . that it was not external in nature. : : :To preclude that situation . . . plug in another radio right beside the Zenith and see if it is also receiving the bursts of inteference . . . if so, then unplug your Zenith to see if the ZENITH is the source of inteference and radiating additionally into the test receiver. : : :Thassssit . . . .'fer now . . . .see how it goes now . . . . : : : : : : :73's de Edd : : :  : |
:
:
:
:
:
:
:
:
:::When the electrolytic failed it probably took down a resistor or two. Measure the voltage as it is divided and you will most likely find an open or arcing or value way up resistor. You should have replaced all the electrolytics when one became unusable.
:::
:::The other possibility is a silver mica that has gone bad. No foolproof way to test, but can produce thunder and crackling. If I have to dismantle an IF can to get at it, I routinely clip out the old one and discard it. In goes a recently manufactured silver mica and I'm done with it.
:
:
:
:
:::
:::::Did you put in the .02 600mfd coupling cap to the grid of the output tube from the plate of the tube before it?
:
:
:
:::::
::::I will check the chassis and see if this cap you are referring to perhaps shorted when the electrolytic did. All of the coupling caps were replaced in the past.
::::
:::
:
:::
::Hi All,
:: Zeniths of this vintage are not susceptable to Silver Mica.
:: The problem could be in an IF, though, such as an intermittant connection.
::
::All the best,
::
::Bill
::
:
:
I failed to mention earlier that I did replace all the electrolytics. Now on to more troubleshooting.
:
:
: : : : : : : : : : : :Sir Dave . . . in Center .Tap . . . . : : : :Looks like a good ole' case of . . . . . Divide and Conquer !. . . . . analytical troubleshooting : : :Specifically, one wants to see if the point of origin is in the audio or the frontal RF section. : : :Initially . . . . hopefully you have it occuring FREQUENTLY enough to be able to confirm it rapidly with multiple evaluative testing probes . : : :(Those units when it only occurs every other-other Thursday . . or occasionally Wednesdays, with the wind out of the NNE, and above 72 . . .but less than 80 degrees, and a blue Ford pickup rumbles down the street . . .. intermittents are real BEARS ! ) : : :Initially if you were to merely bring the volume control to its MINIMUM position, and then listening for a period of time, should confirm its origin as being in the AF output stage or erratic power supply related. . . . considering its presence in that no volume position. : : :Now,that would be nonconfirming of the 1st AF stage, so in order to evaluate it and the detector stage try this: : : :It will be necessary to short out the detector plate of the 6H6 tube, and that can be done by not even pulling the chassis, if you will take but a single strand of ~2-3 in length from the fine copper wire in AC line cord wire and unplug the 6H6 and slip one end down into either pin #3 or 5 and replug in the tube. : : (Now . . . THIMK . . . about identifying that pin(s) 3 or 5, since you are viewing the tube from the TOPSIDE ! ) : : :That then lets you short the other end of the wire to ground and then you can turn up the volume to normal . . or higher level . . .and don't expect stations . . .but DO listen for your burst of interferences presence. : : :If you have then deemed that the noise is no longer present, then your Detector-1st audio-AF output stages must not be the origin areas. : : :That is making the need of the removal of the short necessary to then move forward in the signal stream to the I.F. amplifier, that will be easy with that 1st grid connection being accessible at the grid cap at the top of the 6K7 tube . . . . . so you short that 1st grid cap to ground and then have the volume up and listen for the still presence of the inteference. : : :If all is quiet, then there is the need to remove that shorting out and move forward to the 6A8 mixer stage where you would do the same thing with the G4 grid cap atop that tube and perk up your ears again.. : : :That past procedure should have sequentially isolated each stage to give you some clue as to the point of origin of your inteference within your set. . . . CONSIDERING . . . that it was not external in nature. : : :To preclude that situation . . . plug in another radio right beside the Zenith and see if it is also receiving the bursts of inteference . . . if so, then unplug your Zenith to see if the ZENITH is the source of inteference and radiating additionally into the test receiver. : : :Thassssit . . . .'fer now . . . .see how it goes now . . . . : : : : : : :73's de Edd : : : : |
:
:
:
:
:
:
:
:
:::When the electrolytic failed it probably took down a resistor or two. Measure the voltage as it is divided and you will most likely find an open or arcing or value way up resistor. You should have replaced all the electrolytics when one became unusable.
:::
:::The other possibility is a silver mica that has gone bad. No foolproof way to test, but can produce thunder and crackling. If I have to dismantle an IF can to get at it, I routinely clip out the old one and discard it. In goes a recently manufactured silver mica and I'm done with it.
:
:
:
:
:::
:::::Did you put in the .02 600mfd coupling cap to the grid of the output tube from the plate of the tube before it?
:
:
:
:::::
::::I will check the chassis and see if this cap you are referring to perhaps shorted when the electrolytic did. All of the coupling caps were replaced in the past.
::::
:::
:
:::
::Hi All,
:: Zeniths of this vintage are not susceptable to Silver Mica.
:: The problem could be in an IF, though, such as an intermittant connection.
::
::All the best,
::
::Bill
::
:
:
I failed to mention earlier that I did replace all the electrolytics. Now on to more troubleshooting. The crashing sound is with 0 volume also.
:
:
: : : : : : : : : : : :Sir Dave . . . in Center .Tap . . . . : : : :Looks like a good ole' case of . . . . . Divide and Conquer !. . . . . analytical troubleshooting : : :Specifically, one wants to see if the point of origin is in the audio or the frontal RF section. : : :Initially . . . . hopefully you have it occuring FREQUENTLY enough to be able to confirm it rapidly with multiple evaluative testing probes . : : :(Those units when it only occurs every other-other Thursday . . or occasionally Wednesdays, with the wind out of the NNE, and above 72 . . .but less than 80 degrees, and a blue Ford pickup rumbles down the street . . .. intermittents are real BEARS ! ) : : :Initially if you were to merely bring the volume control to its MINIMUM position, and then listening for a period of time, should confirm its origin as being in the AF output stage or erratic power supply related. . . . considering its presence in that no volume position. : : :Now,that would be nonconfirming of the 1st AF stage, so in order to evaluate it and the detector stage try this: : : :It will be necessary to short out the detector plate of the 6H6 tube, and that can be done by not even pulling the chassis, if you will take but a single strand of ~2-3 in length from the fine copper wire in AC line cord wire and unplug the 6H6 and slip one end down into either pin #3 or 5 and replug in the tube. : : (Now . . . THIMK . . . about identifying that pin(s) 3 or 5, since you are viewing the tube from the TOPSIDE ! ) : : :That then lets you short the other end of the wire to ground and then you can turn up the volume to normal . . or higher level . . .and don't expect stations . . .but DO listen for your burst of interferences presence. : : :If you have then deemed that the noise is no longer present, then your Detector-1st audio-AF output stages must not be the origin areas. : : :That is making the need of the removal of the short necessary to then move forward in the signal stream to the I.F. amplifier, that will be easy with that 1st grid connection being accessible at the grid cap at the top of the 6K7 tube . . . . . so you short that 1st grid cap to ground and then have the volume up and listen for the still presence of the inteference. : : :If all is quiet, then there is the need to remove that shorting out and move forward to the 6A8 mixer stage where you would do the same thing with the G4 grid cap atop that tube and perk up your ears again.. : : :That past procedure should have sequentially isolated each stage to give you some clue as to the point of origin of your inteference within your set. . . . CONSIDERING . . . that it was not external in nature. : : :To preclude that situation . . . plug in another radio right beside the Zenith and see if it is also receiving the bursts of inteference . . . if so, then unplug your Zenith to see if the ZENITH is the source of inteference and radiating additionally into the test receiver. : : :Thassssit . . . .'fer now . . . .see how it goes now . . . . : : : : : : :73's de Edd : : : : |
:
:
:
:
:
:
:
:
:::When the electrolytic failed it probably took down a resistor or two. Measure the voltage as it is divided and you will most likely find an open or arcing or value way up resistor. You should have replaced all the electrolytics when one became unusable.
:::
:::The other possibility is a silver mica that has gone bad. No foolproof way to test, but can produce thunder and crackling. If I have to dismantle an IF can to get at it, I routinely clip out the old one and discard it. In goes a recently manufactured silver mica and I'm done with it.
:
:
:
:
:::
:::::Did you put in the .02 600mfd coupling cap to the grid of the output tube from the plate of the tube before it?
:
:
:
:::::
::::I will check the chassis and see if this cap you are referring to perhaps shorted when the electrolytic did. All of the coupling caps were replaced in the past.
::::
:::
:
:::
::Hi All,
:: Zeniths of this vintage are not susceptable to Silver Mica.
:: The problem could be in an IF, though, such as an intermittant connection.
::
::All the best,
::
::Bill
::
:
:
I failed to mention earlier that I did replace all the electrolytics. Now on to more troubleshooting. The crashing sound is with 0 volume also.
Woooo Hoooo . . . . that then sort of sounds like narrowing it down to the AF stage or possibly power supply /componets induced. Might try a lot of moving / tapping in that sets AF Out --- P/S area on components with a plastic stick or use the plastic handle of a screwdriver for more massive components . . in additionally looking for connectivity / or / cold solder aspects. And for SURE the set either has a new C18 or you have additionally, pulled and subbed in another unit just to be sure . . . . Right ? |
::
::
::
::
::
::
::
::
::
::
::
::
::
::
::
::Sir Dave . . . in Center .Tap . . . .
::
::
::
::Looks like a good ole' case of . . . . . Divide and Conquer !. . . . . analytical troubleshooting
::
::
::Specifically, one wants to see if the point of origin is in the audio or the frontal RF section.
::
::
::Initially . . . . hopefully you have it occuring FREQUENTLY enough to be able to confirm it rapidly with multiple evaluative testing probes .
::
::
::(Those units when it only occurs every other-other Thursday . . or occasionally Wednesdays, with the wind out of the NNE, and above 72 . . .but less than 80 degrees, and a blue Ford pickup rumbles down the street . . .. intermittents are real BEARS ! )
::
::
::Initially if you were to merely bring the volume control to its MINIMUM position, and then listening for a period of time, should confirm its origin as being in the AF output stage or erratic power supply related. . . . considering its presence in that no volume position.
::
::
::Now,that would be nonconfirming of the 1st AF stage, so in order to evaluate it and the detector stage try this:
::
::
::It will be necessary to short out the detector plate of the 6H6 tube, and that can be done by not even pulling the chassis, if you will take but a single strand of ~2-3 in length from the fine copper wire in AC line cord wire and unplug the 6H6 and slip one end down into either pin #3 or 5 and replug in the tube.
::
:: (Now . . . THIMK . . . about identifying that pin(s) 3 or 5, since you are viewing the tube from the TOPSIDE ! )
::
::
::That then lets you short the other end of the wire to ground and then you can turn up the volume to normal . . or higher level . . .and don't expect stations . . .but DO listen for your burst of interferences presence.
::
::
::If you have then deemed that the noise is no longer present, then your Detector-1st audio-AF output stages must not be the origin areas.
::
::
::That is making the need of the removal of the short necessary to then move forward in the signal stream to the I.F. amplifier, that will be easy with that 1st grid connection being accessible at the grid cap at the top of the 6K7 tube . . . . . so you short that 1st grid cap to ground and then have the volume up and listen for the still presence of the inteference.
::
::
::If all is quiet, then there is the need to remove that shorting out and move forward to the 6A8 mixer stage where you would do the same thing with the G4 grid cap atop that tube and perk up your ears again..
::
::
::That past procedure should have sequentially isolated each stage to give you some clue as to the point of origin of your inteference within your set. . . . CONSIDERING . . . that it was not external in nature.
::
::
::To preclude that situation . . . plug in another radio right beside the Zenith and see if it is also receiving the bursts of inteference . . . if so, then unplug your Zenith to see if the ZENITH is the source of inteference and radiating additionally into the test receiver.
::
::
::Thassssit . . . .'fer now . . . .see how it goes now . . . .
::
::
::
::
::
::
::73's de Edd
::
::
::
::
::
::
::
::
::
::
::
::
::::When the electrolytic failed it probably took down a resistor or two. Measure the voltage as it is divided and you will most likely find an open or arcing or value way up resistor. You should have replaced all the electrolytics when one became unusable.
::::
::::The other possibility is a silver mica that has gone bad. No foolproof way to test, but can produce thunder and crackling. If I have to dismantle an IF can to get at it, I routinely clip out the old one and discard it. In goes a recently manufactured silver mica and I'm done with it.
::
::
::
::
::::
::::::Did you put in the .02 600mfd coupling cap to the grid of the output tube from the plate of the tube before it?
::
::
::
::::::
:::::I will check the chassis and see if this cap you are referring to perhaps shorted when the electrolytic did. All of the coupling caps were replaced in the past.
:::::
::::
::
::::
:::Hi All,
::: Zeniths of this vintage are not susceptable to Silver Mica.
::: The problem could be in an IF, though, such as an intermittant connection.
:::
:::All the best,
:::
:::Bill
:::
::::
:I failed to mention earlier that I did replace all the electrolytics. Now on to more troubleshooting. The crashing sound is with 0 volume also.
: