For review, I've been (attempting) restoration on my Philco Model 84. I had to replace the power transformer as it was bad - I was able to get power consumption down to a normal wattage and fix the problem that caused the transformer to go bad in the first place. Previous repairs left the block capacitors full of paper capacitors strapped across the terminals - this mess was what caused the short transformer in the first place. All totaled, I've replaced the transformer, the block capacitors, the electrolytic capacitor, and most of the resistors. Now, I have a radio that is very out of tolerance and receives nothing. I was able to get audio by clipping my test lead between the first grid of the 42 audio tube and ground. So, knowing that my audio stage is fine, I need to work back through the previous stages to solve my problem. This is all that I can determine as of right now. With all of the trimmer capacitors out of adjustment, trying to realign the set seems hopeless to me. Am I right?
Moving on to my questions, what do I do to realign this set???? I've tried the Philco realignment instructions that are in riders, but I cannot get any signal at all. I would really like to check the trimmer capacitors before I continue to troubleshoot...if someone can instruct me on what to do to check those, I would appreciate it. I am still (and always will be) learning at this hobby, and I guess that this is the point where I always get stuck. I will thank you in advance for any help that you can give me, I have always found much help from the members of this forum (Norm, Don, and John especially).
Thanks,
Nicholas
I would start by measuring pin #2 and #3 on your #77 tubes. These pins should be positive.
Alignment of this radio is a little different than most. There are adjustments on back that control feedback of your oscillator.
Was the 4 meg grid resistor ok? Believe it's in a can and hard to locate.
Norm
:Hello,
:
:For review, I've been (attempting) restoration on my Philco Model 84. I had to replace the power transformer as it was bad - I was able to get power consumption down to a normal wattage and fix the problem that caused the transformer to go bad in the first place. Previous repairs left the block capacitors full of paper capacitors strapped across the terminals - this mess was what caused the short transformer in the first place. All totaled, I've replaced the transformer, the block capacitors, the electrolytic capacitor, and most of the resistors. Now, I have a radio that is very out of tolerance and receives nothing. I was able to get audio by clipping my test lead between the first grid of the 42 audio tube and ground. So, knowing that my audio stage is fine, I need to work back through the previous stages to solve my problem. This is all that I can determine as of right now. With all of the trimmer capacitors out of adjustment, trying to realign the set seems hopeless to me. Am I right?
:
:Moving on to my questions, what do I do to realign this set???? I've tried the Philco realignment instructions that are in riders, but I cannot get any signal at all. I would really like to check the trimmer capacitors before I continue to troubleshoot...if someone can instruct me on what to do to check those, I would appreciate it. I am still (and always will be) learning at this hobby, and I guess that this is the point where I always get stuck. I will thank you in advance for any help that you can give me, I have always found much help from the members of this forum (Norm, Don, and John especially).
:
:Thanks,
:
:Nicholas
I thought I might chime in here as I fixed up an 84 that had a similar problem a few weeks ago, and forgot all about the posting of Nicholas'.
The main flaw with mine was an open winding on the oscilator coil. The two windings do tie to a common point, but in the case with mine, one winding had burned open, it happened to be the 14 turns of wire on top of the secondary, which runss the full length of the core. This apparently is a common failure.
I would check the continuity of the windings in the oscillator coil, this is the one coil right next to the filter capacitor.
You can use eneameled wire anywhere from .008" to .010" diameter (this fits the grooves in the lacquer from the old widings, and make it a little easier to rewind.
Once that coil was rewound, alignment was a snap following the instructions.
:Hi Nicholas
:
: I would start by measuring pin #2 and #3 on your #77 tubes. These pins should be positive.
:
: Alignment of this radio is a little different than most. There are adjustments on back that control feedback of your oscillator.
:
: Was the 4 meg grid resistor ok? Believe it's in a can and hard to locate.
:
:Norm
:
::Hello,
::
::For review, I've been (attempting) restoration on my Philco Model 84. I had to replace the power transformer as it was bad - I was able to get power consumption down to a normal wattage and fix the problem that caused the transformer to go bad in the first place. Previous repairs left the block capacitors full of paper capacitors strapped across the terminals - this mess was what caused the short transformer in the first place. All totaled, I've replaced the transformer, the block capacitors, the electrolytic capacitor, and most of the resistors. Now, I have a radio that is very out of tolerance and receives nothing. I was able to get audio by clipping my test lead between the first grid of the 42 audio tube and ground. So, knowing that my audio stage is fine, I need to work back through the previous stages to solve my problem. This is all that I can determine as of right now. With all of the trimmer capacitors out of adjustment, trying to realign the set seems hopeless to me. Am I right?
::
::Moving on to my questions, what do I do to realign this set???? I've tried the Philco realignment instructions that are in riders, but I cannot get any signal at all. I would really like to check the trimmer capacitors before I continue to troubleshoot...if someone can instruct me on what to do to check those, I would appreciate it. I am still (and always will be) learning at this hobby, and I guess that this is the point where I always get stuck. I will thank you in advance for any help that you can give me, I have always found much help from the members of this forum (Norm, Don, and John especially).
::
::Thanks,
::
::Nicholas
John, I find your oscillator coil problem interesting because I remember reading on the internet on some website that another model 84 had the same problem. I checked the 77 tubes: pins 2 and 3 of the 1st Det.-Osc. were 245 and 110 VDC positive respectively. Pins 2 and 3 were 48 and 26 VDC positive respectively. I remember the 4M ohm resistor you are talking about Norm, it was the one that caused alot of confusion when I was replacing resistors. I'll check that again when I check the coil. Thank you to both of you for your help - I'll let you know what I find. (I don't know when I'll have a chance to look at this radio this week as the rest of the week is meetings and its off to Michigan this weekend...but there's always time for radio, right?)
Nicholas
:Hi,
:
:I thought I might chime in here as I fixed up an 84 that had a similar problem a few weeks ago, and forgot all about the posting of Nicholas'.
:
:The main flaw with mine was an open winding on the oscilator coil. The two windings do tie to a common point, but in the case with mine, one winding had burned open, it happened to be the 14 turns of wire on top of the secondary, which runss the full length of the core. This apparently is a common failure.
:
:I would check the continuity of the windings in the oscillator coil, this is the one coil right next to the filter capacitor.
:
:You can use eneameled wire anywhere from .008" to .010" diameter (this fits the grooves in the lacquer from the old widings, and make it a little easier to rewind.
:
:Once that coil was rewound, alignment was a snap following the instructions.
:
::Hi Nicholas
::
:: I would start by measuring pin #2 and #3 on your #77 tubes. These pins should be positive.
::
:: Alignment of this radio is a little different than most. There are adjustments on back that control feedback of your oscillator.
::
:: Was the 4 meg grid resistor ok? Believe it's in a can and hard to locate.
::
::Norm
::
:::Hello,
:::
:::For review, I've been (attempting) restoration on my Philco Model 84. I had to replace the power transformer as it was bad - I was able to get power consumption down to a normal wattage and fix the problem that caused the transformer to go bad in the first place. Previous repairs left the block capacitors full of paper capacitors strapped across the terminals - this mess was what caused the short transformer in the first place. All totaled, I've replaced the transformer, the block capacitors, the electrolytic capacitor, and most of the resistors. Now, I have a radio that is very out of tolerance and receives nothing. I was able to get audio by clipping my test lead between the first grid of the 42 audio tube and ground. So, knowing that my audio stage is fine, I need to work back through the previous stages to solve my problem. This is all that I can determine as of right now. With all of the trimmer capacitors out of adjustment, trying to realign the set seems hopeless to me. Am I right?
:::
:::Moving on to my questions, what do I do to realign this set???? I've tried the Philco realignment instructions that are in riders, but I cannot get any signal at all. I would really like to check the trimmer capacitors before I continue to troubleshoot...if someone can instruct me on what to do to check those, I would appreciate it. I am still (and always will be) learning at this hobby, and I guess that this is the point where I always get stuck. I will thank you in advance for any help that you can give me, I have always found much help from the members of this forum (Norm, Don, and John especially).
:::
:::Thanks,
:::
:::Nicholas
I finally had time to work on the Model 84. I replaced the 4 megohm resistor in question and checked all three of the coils, but none of them were open. (All coils have resistances between 4 and 12 ohms...this seems normal to me.) I did notice that when I hooked the radio up to a strong antenna, I was able to get a weak signal throughout the band. Of course, at maximum volume, the radio was barely audible. I adjusted the trimmers by ear, but I really didn't get much of an improvement. What I did find was this: connecting a .1mfd capacitor across pins 1 and 3 of the bakelite block 20 on the schematic gave me normal volume out of the speaker, although it was a bit distorted. So it would seem that the IF stages are working...partially? Could the earlier short transformer have caused one of the caps I replaced to go bad? I guess I am getting closer to solving the problem, but I still don't know where to go. Please let me know if you have any suggestions.
Thanks again for all of your help,
Nicholas
:Hello,
:
:John, I find your oscillator coil problem interesting because I remember reading on the internet on some website that another model 84 had the same problem. I checked the 77 tubes: pins 2 and 3 of the 1st Det.-Osc. were 245 and 110 VDC positive respectively. Pins 2 and 3 were 48 and 26 VDC positive respectively. I remember the 4M ohm resistor you are talking about Norm, it was the one that caused alot of confusion when I was replacing resistors. I'll check that again when I check the coil. Thank you to both of you for your help - I'll let you know what I find. (I don't know when I'll have a chance to look at this radio this week as the rest of the week is meetings and its off to Michigan this weekend...but there's always time for radio, right?)
:
:Nicholas
::Hi,
::
::I thought I might chime in here as I fixed up an 84 that had a similar problem a few weeks ago, and forgot all about the posting of Nicholas'.
::
::The main flaw with mine was an open winding on the oscilator coil. The two windings do tie to a common point, but in the case with mine, one winding had burned open, it happened to be the 14 turns of wire on top of the secondary, which runss the full length of the core. This apparently is a common failure.
::
::I would check the continuity of the windings in the oscillator coil, this is the one coil right next to the filter capacitor.
::
::You can use eneameled wire anywhere from .008" to .010" diameter (this fits the grooves in the lacquer from the old widings, and make it a little easier to rewind.
::
::Once that coil was rewound, alignment was a snap following the instructions.
::
:::Hi Nicholas
:::
::: I would start by measuring pin #2 and #3 on your #77 tubes. These pins should be positive.
:::
::: Alignment of this radio is a little different than most. There are adjustments on back that control feedback of your oscillator.
:::
::: Was the 4 meg grid resistor ok? Believe it's in a can and hard to locate.
:::
:::Norm
:::
::::Hello,
::::
::::For review, I've been (attempting) restoration on my Philco Model 84. I had to replace the power transformer as it was bad - I was able to get power consumption down to a normal wattage and fix the problem that caused the transformer to go bad in the first place. Previous repairs left the block capacitors full of paper capacitors strapped across the terminals - this mess was what caused the short transformer in the first place. All totaled, I've replaced the transformer, the block capacitors, the electrolytic capacitor, and most of the resistors. Now, I have a radio that is very out of tolerance and receives nothing. I was able to get audio by clipping my test lead between the first grid of the 42 audio tube and ground. So, knowing that my audio stage is fine, I need to work back through the previous stages to solve my problem. This is all that I can determine as of right now. With all of the trimmer capacitors out of adjustment, trying to realign the set seems hopeless to me. Am I right?
::::
::::Moving on to my questions, what do I do to realign this set???? I've tried the Philco realignment instructions that are in riders, but I cannot get any signal at all. I would really like to check the trimmer capacitors before I continue to troubleshoot...if someone can instruct me on what to do to check those, I would appreciate it. I am still (and always will be) learning at this hobby, and I guess that this is the point where I always get stuck. I will thank you in advance for any help that you can give me, I have always found much help from the members of this forum (Norm, Don, and John especially).
::::
::::Thanks,
::::
::::Nicholas
At this point, probably replacing that one cap might be a good idea. As long as working voltages of the replacement caps is adequate (250 WVDC, or a little bit higher), the caps should not fail. But there is a possibility that unless you knew the replacement was a new fresh stock item, that cap may have been defective. I have encountered faulty replacement stock on a few occaisions, so even with new- it can happen, but it seems to become more common as the replacement pieces are of older vintage.
:Hello,
:
:I finally had time to work on the Model 84. I replaced the 4 megohm resistor in question and checked all three of the coils, but none of them were open. (All coils have resistances between 4 and 12 ohms...this seems normal to me.) I did notice that when I hooked the radio up to a strong antenna, I was able to get a weak signal throughout the band. Of course, at maximum volume, the radio was barely audible. I adjusted the trimmers by ear, but I really didn't get much of an improvement. What I did find was this: connecting a .1mfd capacitor across pins 1 and 3 of the bakelite block 20 on the schematic gave me normal volume out of the speaker, although it was a bit distorted. So it would seem that the IF stages are working...partially? Could the earlier short transformer have caused one of the caps I replaced to go bad? I guess I am getting closer to solving the problem, but I still don't know where to go. Please let me know if you have any suggestions.
:
:Thanks again for all of your help,
:
:Nicholas
:
:
::Hello,
::
::John, I find your oscillator coil problem interesting because I remember reading on the internet on some website that another model 84 had the same problem. I checked the 77 tubes: pins 2 and 3 of the 1st Det.-Osc. were 245 and 110 VDC positive respectively. Pins 2 and 3 were 48 and 26 VDC positive respectively. I remember the 4M ohm resistor you are talking about Norm, it was the one that caused alot of confusion when I was replacing resistors. I'll check that again when I check the coil. Thank you to both of you for your help - I'll let you know what I find. (I don't know when I'll have a chance to look at this radio this week as the rest of the week is meetings and its off to Michigan this weekend...but there's always time for radio, right?)
::
::Nicholas
:::Hi,
:::
:::I thought I might chime in here as I fixed up an 84 that had a similar problem a few weeks ago, and forgot all about the posting of Nicholas'.
:::
:::The main flaw with mine was an open winding on the oscilator coil. The two windings do tie to a common point, but in the case with mine, one winding had burned open, it happened to be the 14 turns of wire on top of the secondary, which runss the full length of the core. This apparently is a common failure.
:::
:::I would check the continuity of the windings in the oscillator coil, this is the one coil right next to the filter capacitor.
:::
:::You can use eneameled wire anywhere from .008" to .010" diameter (this fits the grooves in the lacquer from the old widings, and make it a little easier to rewind.
:::
:::Once that coil was rewound, alignment was a snap following the instructions.
:::
::::Hi Nicholas
::::
:::: I would start by measuring pin #2 and #3 on your #77 tubes. These pins should be positive.
::::
:::: Alignment of this radio is a little different than most. There are adjustments on back that control feedback of your oscillator.
::::
:::: Was the 4 meg grid resistor ok? Believe it's in a can and hard to locate.
::::
::::Norm
::::
:::::Hello,
:::::
:::::For review, I've been (attempting) restoration on my Philco Model 84. I had to replace the power transformer as it was bad - I was able to get power consumption down to a normal wattage and fix the problem that caused the transformer to go bad in the first place. Previous repairs left the block capacitors full of paper capacitors strapped across the terminals - this mess was what caused the short transformer in the first place. All totaled, I've replaced the transformer, the block capacitors, the electrolytic capacitor, and most of the resistors. Now, I have a radio that is very out of tolerance and receives nothing. I was able to get audio by clipping my test lead between the first grid of the 42 audio tube and ground. So, knowing that my audio stage is fine, I need to work back through the previous stages to solve my problem. This is all that I can determine as of right now. With all of the trimmer capacitors out of adjustment, trying to realign the set seems hopeless to me. Am I right?
:::::
:::::Moving on to my questions, what do I do to realign this set???? I've tried the Philco realignment instructions that are in riders, but I cannot get any signal at all. I would really like to check the trimmer capacitors before I continue to troubleshoot...if someone can instruct me on what to do to check those, I would appreciate it. I am still (and always will be) learning at this hobby, and I guess that this is the point where I always get stuck. I will thank you in advance for any help that you can give me, I have always found much help from the members of this forum (Norm, Don, and John especially).
:::::
:::::Thanks,
:::::
:::::Nicholas
At this point, probably replacing that one cap might be a good idea. As long as working voltages of the replacement caps is adequate (250 WVDC, or a little bit higher), the caps should not fail. But there is a possibility that unless you knew the replacement was a new fresh stock item, that cap may have been defective. I have encountered faulty replacement stock on a few occaisions, so even with new- it can happen, but it seems to become more common as the replacement pieces are of older vintage.
:Hello,
:
:I finally had time to work on the Model 84. I replaced the 4 megohm resistor in question and checked all three of the coils, but none of them were open. (All coils have resistances between 4 and 12 ohms...this seems normal to me.) I did notice that when I hooked the radio up to a strong antenna, I was able to get a weak signal throughout the band. Of course, at maximum volume, the radio was barely audible. I adjusted the trimmers by ear, but I really didn't get much of an improvement. What I did find was this: connecting a .1mfd capacitor across pins 1 and 3 of the bakelite block 20 on the schematic gave me normal volume out of the speaker, although it was a bit distorted. So it would seem that the IF stages are working...partially? Could the earlier short transformer have caused one of the caps I replaced to go bad? I guess I am getting closer to solving the problem, but I still don't know where to go. Please let me know if you have any suggestions.
:
:Thanks again for all of your help,
:
:Nicholas
:
:
::Hello,
::
::John, I find your oscillator coil problem interesting because I remember reading on the internet on some website that another model 84 had the same problem. I checked the 77 tubes: pins 2 and 3 of the 1st Det.-Osc. were 245 and 110 VDC positive respectively. Pins 2 and 3 were 48 and 26 VDC positive respectively. I remember the 4M ohm resistor you are talking about Norm, it was the one that caused alot of confusion when I was replacing resistors. I'll check that again when I check the coil. Thank you to both of you for your help - I'll let you know what I find. (I don't know when I'll have a chance to look at this radio this week as the rest of the week is meetings and its off to Michigan this weekend...but there's always time for radio, right?)
::
::Nicholas
:::Hi,
:::
:::I thought I might chime in here as I fixed up an 84 that had a similar problem a few weeks ago, and forgot all about the posting of Nicholas'.
:::
:::The main flaw with mine was an open winding on the oscilator coil. The two windings do tie to a common point, but in the case with mine, one winding had burned open, it happened to be the 14 turns of wire on top of the secondary, which runss the full length of the core. This apparently is a common failure.
:::
:::I would check the continuity of the windings in the oscillator coil, this is the one coil right next to the filter capacitor.
:::
:::You can use eneameled wire anywhere from .008" to .010" diameter (this fits the grooves in the lacquer from the old widings, and make it a little easier to rewind.
:::
:::Once that coil was rewound, alignment was a snap following the instructions.
:::
::::Hi Nicholas
::::
:::: I would start by measuring pin #2 and #3 on your #77 tubes. These pins should be positive.
::::
:::: Alignment of this radio is a little different than most. There are adjustments on back that control feedback of your oscillator.
::::
:::: Was the 4 meg grid resistor ok? Believe it's in a can and hard to locate.
::::
::::Norm
::::
:::::Hello,
:::::
:::::For review, I've been (attempting) restoration on my Philco Model 84. I had to replace the power transformer as it was bad - I was able to get power consumption down to a normal wattage and fix the problem that caused the transformer to go bad in the first place. Previous repairs left the block capacitors full of paper capacitors strapped across the terminals - this mess was what caused the short transformer in the first place. All totaled, I've replaced the transformer, the block capacitors, the electrolytic capacitor, and most of the resistors. Now, I have a radio that is very out of tolerance and receives nothing. I was able to get audio by clipping my test lead between the first grid of the 42 audio tube and ground. So, knowing that my audio stage is fine, I need to work back through the previous stages to solve my problem. This is all that I can determine as of right now. With all of the trimmer capacitors out of adjustment, trying to realign the set seems hopeless to me. Am I right?
:::::
:::::Moving on to my questions, what do I do to realign this set???? I've tried the Philco realignment instructions that are in riders, but I cannot get any signal at all. I would really like to check the trimmer capacitors before I continue to troubleshoot...if someone can instruct me on what to do to check those, I would appreciate it. I am still (and always will be) learning at this hobby, and I guess that this is the point where I always get stuck. I will thank you in advance for any help that you can give me, I have always found much help from the members of this forum (Norm, Don, and John especially).
:::::
:::::Thanks,
:::::
:::::Nicholas
I finally had time to work on the Model 84. I replaced the 4 megohm resistor in question and checked all three of the coils, but none of them were open. (All coils have resistances between 4 and 12 ohms...this seems normal to me.) I did notice that when I hooked the radio up to a strong antenna, I was able to get a weak signal throughout the band. Of course, at maximum volume, the radio was barely audible. I adjusted the trimmers by ear, but I really didn't get much of an improvement. What I did find was this: connecting a .1mfd capacitor across pins 1 and 3 of the bakelite block 20 on the schematic gave me normal volume out of the speaker, although it was a bit distorted. So it would seem that the IF stages are working...partially? Could the earlier short transformer have caused one of the caps I replaced to go bad? I guess I am getting closer to solving the problem, but I still don't know where to go. Please let me know if you have any suggestions.
Thanks again for all of your help,
Nicholas
:Hello,
:
:John, I find your oscillator coil problem interesting because I remember reading on the internet on some website that another model 84 had the same problem. I checked the 77 tubes: pins 2 and 3 of the 1st Det.-Osc. were 245 and 110 VDC positive respectively. Pins 2 and 3 were 48 and 26 VDC positive respectively. I remember the 4M ohm resistor you are talking about Norm, it was the one that caused alot of confusion when I was replacing resistors. I'll check that again when I check the coil. Thank you to both of you for your help - I'll let you know what I find. (I don't know when I'll have a chance to look at this radio this week as the rest of the week is meetings and its off to Michigan this weekend...but there's always time for radio, right?)
:
:Nicholas
::Hi,
::
::I thought I might chime in here as I fixed up an 84 that had a similar problem a few weeks ago, and forgot all about the posting of Nicholas'.
::
::The main flaw with mine was an open winding on the oscilator coil. The two windings do tie to a common point, but in the case with mine, one winding had burned open, it happened to be the 14 turns of wire on top of the secondary, which runss the full length of the core. This apparently is a common failure.
::
::I would check the continuity of the windings in the oscillator coil, this is the one coil right next to the filter capacitor.
::
::You can use eneameled wire anywhere from .008" to .010" diameter (this fits the grooves in the lacquer from the old widings, and make it a little easier to rewind.
::
::Once that coil was rewound, alignment was a snap following the instructions.
::
:::Hi Nicholas
:::
::: I would start by measuring pin #2 and #3 on your #77 tubes. These pins should be positive.
:::
::: Alignment of this radio is a little different than most. There are adjustments on back that control feedback of your oscillator.
:::
::: Was the 4 meg grid resistor ok? Believe it's in a can and hard to locate.
:::
:::Norm
:::
::::Hello,
::::
::::For review, I've been (attempting) restoration on my Philco Model 84. I had to replace the power transformer as it was bad - I was able to get power consumption down to a normal wattage and fix the problem that caused the transformer to go bad in the first place. Previous repairs left the block capacitors full of paper capacitors strapped across the terminals - this mess was what caused the short transformer in the first place. All totaled, I've replaced the transformer, the block capacitors, the electrolytic capacitor, and most of the resistors. Now, I have a radio that is very out of tolerance and receives nothing. I was able to get audio by clipping my test lead between the first grid of the 42 audio tube and ground. So, knowing that my audio stage is fine, I need to work back through the previous stages to solve my problem. This is all that I can determine as of right now. With all of the trimmer capacitors out of adjustment, trying to realign the set seems hopeless to me. Am I right?
::::
::::Moving on to my questions, what do I do to realign this set???? I've tried the Philco realignment instructions that are in riders, but I cannot get any signal at all. I would really like to check the trimmer capacitors before I continue to troubleshoot...if someone can instruct me on what to do to check those, I would appreciate it. I am still (and always will be) learning at this hobby, and I guess that this is the point where I always get stuck. I will thank you in advance for any help that you can give me, I have always found much help from the members of this forum (Norm, Don, and John especially).
::::
::::Thanks,
::::
::::Nicholas