This should be a good radio with RF stage. Have you peaked up IF Transformers?
http://www.nostalgiaair.org/PagesByModel/881/M0010881.pdf
Norm
:Have radio working well but does not seem to pick up near as many local stations as others I have. Any "SIMPLE" ways to increase reception on this jewel before I put it all back together and into the ole collection?????
:
: This should be a good radio with RF stage. Have you peaked up IF Transformers?
:
:http://www.nostalgiaair.org/PagesByModel/881/M0010881.pdf
:
:Norm
:
No, and I don't really know how or if I have the correct tools to do so. I replaced all caps,bad tubes,bad wires,really cleaned everything,etc. I'm getting better but am pretty new at this so am pretty limited technically.
::Have radio working well but does not seem to pick up near as many local stations as others I have. Any "SIMPLE" ways to increase reception on this jewel before I put it all back together and into the ole collection?????
IF Transformers are identified as 20-10 and 20-11 in the schematic. Each one is usually a square can on top the chassis. These cans each have two adjusting screws.
You don't need special equipment to get the adjustment close. With a screwdriver, or whatever fits the adjustments, turn each screw. Look for point of max volume.
Shouldn't have a problem but you might want to mark the starting points of each adjustment?
Norm
::Mike
::
:: This should be a good radio with RF stage. Have you peaked up IF Transformers?
::
::http://www.nostalgiaair.org/PagesByModel/881/M0010881.pdf
::
::Norm
::
:No, and I don't really know how or if I have the correct tools to do so. I replaced all caps,bad tubes,bad wires,really cleaned everything,etc. I'm getting better but am pretty new at this so am pretty limited technically.
:::Have radio working well but does not seem to pick up near as many local stations as others I have. Any "SIMPLE" ways to increase reception on this jewel before I put it all back together and into the ole collection?????
bunch!! AGAIN!!!
:
: IF Transformers are identified as 20-10 and 20-11 in the schematic. Each one is usually a square can on top the chassis. These cans each have two adjusting screws.
:
: You don't need special equipment to get the adjustment close. With a screwdriver, or whatever fits the adjustments, turn each screw. Look for point of max volume.
:
: Shouldn't have a problem but you might want to mark the starting points of each adjustment?
:
:Norm
:
:::Mike
:::
::: This should be a good radio with RF stage. Have you peaked up IF Transformers?
:::
:::http://www.nostalgiaair.org/PagesByModel/881/M0010881.pdf
:::
:::Norm
:::
::No, and I don't really know how or if I have the correct tools to do so. I replaced all caps,bad tubes,bad wires,really cleaned everything,etc. I'm getting better but am pretty new at this so am pretty limited technically.
::::Have radio working well but does not seem to pick up near as many local stations as others I have. Any "SIMPLE" ways to increase reception on this jewel before I put it all back together and into the ole collection?????
HEADER ADDENDA……I had initially composed this reply last night using voice recognition and had semi-proofed but found that my markup schema was on a Flash left at another site..only now accessible… so I am attaching schema and submitting in addition, in case pertinent info will help in furthering the optimization of “Minnies” performance…since she was initially described as having such abysmally bucolic reception performance.
Gosh yes….. after seeing your sets schematic…that set should be performing like a screaming Meeeeeemie Minoooi-va…..what with it even utilizing an RF stage in the front end. Its only shortcoming being that its not utilizing an extra tuned LC stage for the plate circuit of the RF amp, with it utilizing a less efficient plate load resistor and making capacitive coupling on into the mixer RF stage.
Should there be any suspicion of fault in the RF frontal stage, you might make a quick evaluation by taking about 5-6 feet of interconnected jumper / test leads
…or wire…and clip one end up vertically in the air and take the free bottom end and clip onto the frontal RF stage at point [A] on the provided schema. Make an evaluation on the reception performance and then move the clip over to point [B] and see what happens, if the performance is improved with that connection there is some deficiency, then some investigation of the RF frontal stage area is in order.
Also referring to the aforementioned suggestion of checking of the IF alignment of the receiver, we don’t know what equipment that you possess, so considering that you have “nuttin” except, at the least , the minimum of a DC metering device.
Try this:
Since your receiver is utilizing a 455 tuning of its IF strip, why not use a freebie for a precise alignment standard, the close held tolerance of an actual transmitting stations signal.
In the past, I made a list of active stations operating on that frequency.(Alphabetically by States) In my case, I use the Sherman station, even in the daytime.
KIYU 910 kHz AM AK Gatlena
WZMG 910 kHz AM AL Opelika
KFYI 910 kHz AM AZ. Phoenix
KECR 910 kHz AM CA El Cajon
KNEW 910 kHz AM CA Oakland
WLAT 910 kHz AM CN HARTFORD
KPOF 910 kHz AM CO Denver Belleview College)
WNEZ 910 kHz AM CT New Britain
WSUI 910 kHz AM IA Iowa City (Univ of Iowa)
WABI 910 kHz AM ME Bangor
WALT 910 kHz AM MS Meridian
KBLG 910 kHz AM MT Billings
WFDF 910 kHz AM MI Flint
WGTO 910 kHz AM MI Cassopolis
KBIM 910 kHz AM NM Roswell
WYLI 910 kHz AM OH Marietta
WPFB 910 kHz AM OH Middletown
KTRO 910 kHz AM OR Portland
WGBI 910 kHz AM PA Scranton
WSBA 910 kHz AM PA York
WORD 910 kHz AM SC Spartanburg
KJJQ 910 kHz AM SD Volga
KURY 910 kHz AM SD Brookings
WJCW 910 kHz AM TN Johnson City
KNAF 910 kHz AM TX Fredericksburg
KRIO 910 kHz AM TX McAllen
KXEB 910 kHz AM TX Sherman
KALL 910 kHz AM UT Salt Lake City
KWDZ 910 kHz AM UT Salt Lake City
WRNL 910 kHz AM VA Richmond
KFXX 910 kHz AM WA Vancouver
Should it be that your I.F. transformers trimmer caps are possibly grossly mis adjusted, it might require an initial rough tune in using one of the weaker stations ( of any frequency) and then trimming in aurally to that station. Initially, take a micro Sharpie marker and place a “tick mark” at one side of the screws slot in referencing to another made on the cans housing just to the side of the access hole. That way, you can find your way “out of the woods” and back home to the initial setting by counting turns, just in case there was a gross miss adjustment of that trimmer(s). Usually less than 1 turn is required MAX.
In an actual IF precise tuned alignment setting, an adjustment can be as close as 1/50th of a single turn of a trimmer….to be covered ahead.
Peak each of the sets 4 IF trimmers for the best audio reception.
To go ahead and perform a more exacting alignment of the set, follow this procedure:
After finding one of these stations…(in your particular locale… it might take nighttime receptions enhanced characteristics)… you can then tune in and peak onto the precise second harmonic (2x) of your desired IF frequency.
For the precise metering involved, this would require DC metering of the developed AVC (Yellow Markup) voltage of the receiver which is being created in a balanced relationship with the strength of the received station. This created voltage is generated as a negative voltage, such, by the using of that particular polarity, will permit it to be applied back to the frontal RF-MIXER-IF stages as a 1st grid biasing voltage to throttle back the amplification of those stages on receiving the stronger stations…where all of the available RF gain is not actually required….nor desired. On the weaker stations, no gain limiting is desired, so un-throttled amplification is permitted.
The mentioned metering is taken on that AVC voltage and will be affected by the metering medium. Since we are dealing with a feebler static type of voltage …rather than a husky dynamic voltage…. the metering medium can load it down and pull it down in value. The very best unit would be a tube type VTVM or its equivalency in a Field Effect Voltmeter or Transistor Volt Meter in the solid state categories. OR the modern…and common… digital voltmeter will also exhibit extreme low loading on that AVC buss, and be equally usable, with the only inconvenience of a transitional bobbling up and down of the digital displays readout. (If you happen to have one (Fluke) that has a combined “analog” scale logging of hash marks, that helps on bit quicker visual response to metering value changes.)
The more invasive metering would be the older analog VOM’s like the Tripletts (630’s) and Simpsons (260) and their ~20k loads presented to the AVC buss
But those WILL work…..and have sufficed for decades…… even though your reading will be loaded down to produce a lower level, you can still differentiate the PEAK of a levels reading.
To put all info into practice now, take the metering and have the positive metering terminal making connection to the negative termination(s)of Miss Minnies B+ supply, and the negative terminal will go to the markups point [C] or there is a stronger level option at [C’] if an adequate level of reading was unavailable.
That will be giving a reading of a negative voltages value. Since you probably have the individual IF tuned stages tuned into the ballpark already, you need to then start with the pr-eee-cise tuning into of one of the above 950 kHz references. Do multiple side to side station tunings and end up with the peak negative AVC voltage read out on the metering…don’t even breathe near that tuning adj.
Start at the far right trimmer screws slot, using an insulated adjustment screwdriver..or one homemade from an orange stick , plastic stock, hardwood dowel stock, Bakelite fiber stock, Epoxy fiberglass stock…what have you, that will work. They are usually quite durable as you are not having to torque something down to inch pounds; one is merely turning a screw; plus, the tiplet itself can be re- sharpened.
Set IF trimmer [1] so that the produced AVC level is built up to a peak reading and then rock either side and leave it tuned to its peak and then start the same procedure on the other [2-4] trimmer sets in the same manner of peaking the adjustments. If you like, at the end, you can go back and repeat those same adjustments again and then you will see the validity of my statement of a minute fraction of a turn on an adjustment and its effect on gain.
In the sequence of passing of an IF signal down the strip, each of the progressive little -2%….-3%…-5% mistuning incremental errors…. being then amplified…can have a cumulative effect on the progressive end result of the strips total gain.
Any final tuning then would be the tuning of the LC series IF trap dropping down off pin 8 of the mixer. In this one case you are wanting to tune for a MINUMUM reading on the output reading, since we are wanting a harmonic IF trapping action.
Thassit
Schematicus Referencimus:
73's de Edd
::Mike: Worked like a dream and was a EASY fix. Thanks a
:bunch!! AGAIN!!!
::
:: IF Transformers are identified as 20-10 and 20-11 in the schematic. Each one is usually a square can on top the chassis. These cans each have two adjusting screws.
::
:: You don't need special equipment to get the adjustment close. With a screwdriver, or whatever fits the adjustments, turn each screw. Look for point of max volume.
::
:: Shouldn't have a problem but you might want to mark the starting points of each adjustment?
::
::Norm
::
::::Mike
::::
:::: This should be a good radio with RF stage. Have you peaked up IF Transformers?
::::
::::http://www.nostalgiaair.org/PagesByModel/881/M0010881.pdf
::::
::::Norm
::::
:::No, and I don't really know how or if I have the correct tools to do so. I replaced all caps,bad tubes,bad wires,really cleaned everything,etc. I'm getting better but am pretty new at this so am pretty limited technically.
:::::Have radio working well but does not seem to pick up near as many local stations as others I have. Any "SIMPLE" ways to increase reception on this jewel before I put it all back together and into the ole collection?????
:
:
:
: HEADER ADDENDA……I had initially composed this reply last night using voice recognition and had semi-proofed but found that my markup schema was on a Flash left at another site..only now accessible… so I am attaching schema and submitting in addition, in case pertinent info will help in furthering the optimization of “Minnies” performance…since she was initially described as having such abysmally bucolic reception performance.
:
:
:
:
:Gosh yes….. after seeing your sets schematic…that set should be performing like a screaming Meeeeeemie Minoooi-va…..what with it even utilizing an RF stage in the front end. Its only shortcoming being that its not utilizing an extra tuned LC stage for the plate circuit of the RF amp, with it utilizing a less efficient plate load resistor and making capacitive coupling on into the mixer RF stage.
:
:Should there be any suspicion of fault in the RF frontal stage, you might make a quick evaluation by taking about 5-6 feet of interconnected jumper / test leads
: …or wire…and clip one end up vertically in the air and take the free bottom end and clip onto the frontal RF stage at point [A] on the provided schema. Make an evaluation on the reception performance and then move the clip over to point [B] and see what happens, if the performance is improved with that connection there is some deficiency, then some investigation of the RF frontal stage area is in order.
:
:
:Also referring to the aforementioned suggestion of checking of the IF alignment of the receiver, we don’t know what equipment that you possess, so considering that you have “nuttin” except, at the least , the minimum of a DC metering device.
:
:
:Try this:
:
:
:Since your receiver is utilizing a 455 tuning of its IF strip, why not use a freebie for a precise alignment standard, the close held tolerance of an actual transmitting stations signal.
: In the past, I made a list of active stations operating on that frequency.(Alphabetically by States) In my case, I use the Sherman station, even in the daytime.
:
:
:
:KIYU 910 kHz AM AK Gatlena
:
:WZMG 910 kHz AM AL Opelika
:
:KFYI 910 kHz AM AZ. Phoenix
:
:KECR 910 kHz AM CA El Cajon
:
:KNEW 910 kHz AM CA Oakland
:
:WLAT 910 kHz AM CN HARTFORD
:
:KPOF 910 kHz AM CO Denver Belleview College)
:
:WNEZ 910 kHz AM CT New Britain
:
:WSUI 910 kHz AM IA Iowa City (Univ of Iowa)
:
:WABI 910 kHz AM ME Bangor
:
:WALT 910 kHz AM MS Meridian
:
:KBLG 910 kHz AM MT Billings
:
:WFDF 910 kHz AM MI Flint
:
:WGTO 910 kHz AM MI Cassopolis
:
:KBIM 910 kHz AM NM Roswell
:
:WYLI 910 kHz AM OH Marietta
:
:WPFB 910 kHz AM OH Middletown
:
:KTRO 910 kHz AM OR Portland
:
:WGBI 910 kHz AM PA Scranton
:
:WSBA 910 kHz AM PA York
:
:WORD 910 kHz AM SC Spartanburg
:
:KJJQ 910 kHz AM SD Volga
:
:KURY 910 kHz AM SD Brookings
:
:WJCW 910 kHz AM TN Johnson City
:
:KNAF 910 kHz AM TX Fredericksburg
:
:KRIO 910 kHz AM TX McAllen
:
:KXEB 910 kHz AM TX Sherman
:
:KALL 910 kHz AM UT Salt Lake City
:
:KWDZ 910 kHz AM UT Salt Lake City
:
:WRNL 910 kHz AM VA Richmond
:
:KFXX 910 kHz AM WA Vancouver
:
:
:
:Should it be that your I.F. transformers trimmer caps are possibly grossly mis adjusted, it might require an initial rough tune in using one of the weaker stations ( of any frequency) and then trimming in aurally to that station. Initially, take a micro Sharpie marker and place a “tick mark” at one side of the screws slot in referencing to another made on the cans housing just to the side of the access hole. That way, you can find your way “out of the woods” and back home to the initial setting by counting turns, just in case there was a gross miss adjustment of that trimmer(s). Usually less than 1 turn is required MAX.
:
:In an actual IF precise tuned alignment setting, an adjustment can be as close as 1/50th of a single turn of a trimmer….to be covered ahead.
:
:Peak each of the sets 4 IF trimmers for the best audio reception.
:
:
:
:To go ahead and perform a more exacting alignment of the set, follow this procedure:
:
:
:After finding one of these stations…(in your particular locale… it might take nighttime receptions enhanced characteristics)… you can then tune in and peak onto the precise second harmonic (2x) of your desired IF frequency.
:
:For the precise metering involved, this would require DC metering of the developed AVC (Yellow Markup) voltage of the receiver which is being created in a balanced relationship with the strength of the received station. This created voltage is generated as a negative voltage, such, by the using of that particular polarity, will permit it to be applied back to the frontal RF-MIXER-IF stages as a 1st grid biasing voltage to throttle back the amplification of those stages on receiving the stronger stations…where all of the available RF gain is not actually required….nor desired. On the weaker stations, no gain limiting is desired, so un-throttled amplification is permitted.
:
:The mentioned metering is taken on that AVC voltage and will be affected by the metering medium. Since we are dealing with a feebler static type of voltage …rather than a husky dynamic voltage…. the metering medium can load it down and pull it down in value. The very best unit would be a tube type VTVM or its equivalency in a Field Effect Voltmeter or Transistor Volt Meter in the solid state categories. OR the modern…and common… digital voltmeter will also exhibit extreme low loading on that AVC buss, and be equally usable, with the only inconvenience of a transitional bobbling up and down of the digital displays readout. (If you happen to have one (Fluke) that has a combined “analog” scale logging of hash marks, that helps on bit quicker visual response to metering value changes.)
:The more invasive metering would be the older analog VOM’s like the Tripletts (630’s) and Simpsons (260) and their ~20k loads presented to the AVC buss
:But those WILL work…..and have sufficed for decades…… even though your reading will be loaded down to produce a lower level, you can still differentiate the PEAK of a levels reading.
:
:
:
:To put all info into practice now, take the metering and have the positive metering terminal making connection to the negative termination(s)of Miss Minnies B+ supply, and the negative terminal will go to the markups point [C] or there is a stronger level option at [C’] if an adequate level of reading was unavailable.
:That will be giving a reading of a negative voltages value. Since you probably have the individual IF tuned stages tuned into the ballpark already, you need to then start with the pr-eee-cise tuning into of one of the above 950 kHz references. Do multiple side to side station tunings and end up with the peak negative AVC voltage read out on the metering…don’t even breathe near that tuning adj.
:
:Start at the far right trimmer screws slot, using an insulated adjustment screwdriver..or one homemade from an orange stick , plastic stock, hardwood dowel stock, Bakelite fiber stock, Epoxy fiberglass stock…what have you, that will work. They are usually quite durable as you are not having to torque something down to inch pounds; one is merely turning a screw; plus, the tiplet itself can be re- sharpened.
:
:Set IF trimmer [1] so that the produced AVC level is built up to a peak reading and then rock either side and leave it tuned to its peak and then start the same procedure on the other [2-4] trimmer sets in the same manner of peaking the adjustments. If you like, at the end, you can go back and repeat those same adjustments again and then you will see the validity of my statement of a minute fraction of a turn on an adjustment and its effect on gain.
:
:In the sequence of passing of an IF signal down the strip, each of the progressive little -2%….-3%…-5% mistuning incremental errors…. being then amplified…can have a cumulative effect on the progressive end result of the strips total gain.
:
:Any final tuning then would be the tuning of the LC series IF trap dropping down off pin 8 of the mixer. In this one case you are wanting to tune for a MINUMUM reading on the output reading, since we are wanting a harmonic IF trapping action.
:
:Thassit
:
:
:
:Schematicus Referencimus:
:
:
:
:
:
:
:
:73's de Edd
:
:
:
:
:
:
:
:
:
:
:::Mike: Worked like a dream and was a EASY fix. Thanks a
::bunch!! AGAIN!!!
:::
::: IF Transformers are identified as 20-10 and 20-11 in the schematic. Each one is usually a square can on top the chassis. These cans each have two adjusting screws.
:::
::: You don't need special equipment to get the adjustment close. With a screwdriver, or whatever fits the adjustments, turn each screw. Look for point of max volume.
:::
::: Shouldn't have a problem but you might want to mark the starting points of each adjustment?
:::
:::Norm
:::
:::::Mike
:::::
::::: This should be a good radio with RF stage. Have you peaked up IF Transformers?
:::::
:::::http://www.nostalgiaair.org/PagesByModel/881/M0010881.pdf
:::::
:::::Norm
:::::
::::No, and I don't really know how or if I have the correct tools to do so. I replaced all caps,bad tubes,bad wires,really cleaned everything,etc. I'm getting better but am pretty new at this so am pretty limited technically.
::::::Have radio working well but does not seem to pick up near as many local stations as others I have. Any "SIMPLE" ways to increase reception on this jewel before I put it all back together and into the ole collection?????