Thanks
Elton
:
Hi warren that is exacly waht I did, radio is working somewhat now, but can't get the high end of the dial to line up I am getting 1250 at the 1600 end. same with SW band so not sure if it is mechanical or another issue in the front end?
E.
:
Well that is just it, went thru the whole alignment procedure , and the 1500 settings can only adjust to 1250 with the padder, and my 18 MC only will adjust to 17.5
not sure why as the rest of the adjustments went perfect.
E.
:
Well I think I found the problem I set my generator for 455 and nothing comes thru on the radio, I rocked the dial on my signal gen and the signal is loud and clear at 640 kz. I know my sig gen is not that far off as I checked it with my digital SW set. What would cause the IF's to be so far out of whack ?
Thanks
E.
:
getting nothing from the generator at 455 with the radio set at 600 kz. as I said signal resonates thru the IF's at 640? I figure it must be something off value causing this . Probably why the AM dial is way off on the final alignment.
E.
If not, you work between the two adjustments, ( oscillator shunt trimmer "F" for the low frequency tracking), and the "J" padder for the high end of the BC band tracking, until the 2 adjustments balance out . ( Those adjustments will be s- t -r -e- t- c -h- i- n -g or compressing the stations placemnents across the dial scale.)
|
:You won’t get anything at 455KC with the IF being so far off. Turn the attenuator up on the signal generator, then adjust the 2nd IF first. Then the first. When you start getting a signal though, turn the attenuation back down.
:
:
:
: : : :  : :Hi edd, I have tried balencing the f and j adjustments as you sugested , the f padder will adjust only so far then stops moving the stations, I see on the tuner the k adjustment for SW there is a small nut on each gang could these be adjusted even though the directions do not call for it? they are both awful rusty, so have not touched them... : : : : : :Sir Elton . . . . . : : :I'm 'jes referrring between two threads and " consuming " that your Zee-nuts radio referred to on this thread is the 6S556. : : :I can't visualize that IF alignment being capable of shifting the range ALLLLL the way up to 670 from 455, which would be minimal capacitance being set on the IF transformers adjustments. :When you get the 455 test signal coming on thru the unit O.K. at 455, then if you still find that the 1500 Khz " received station" is coming in at 1250. There would be excessive capacitance in the setting of "J" broadcast padder adjustment. : : :As you then progressively DECREASE its capacitance value, (decreasing the compression of the leaves of trimmer ) the received station should then " walk" its position on up the dial scale towards that required 1500 Khz setting. : : :Then you check back at the low end of the band to see if earlier set 640 alignment is still in congruence . : :If not, you work between the two adjustments, ( oscillator shunt trimmer "F" for the low frequency tracking), and the "J" padder for the high end of the BC band tracking, until the 2 adjustments balance out . ( Those adjustments will be s- t -r -e- t- c -h- i- n -g or compressing the stations placemnents across the dial scale.) : : : : : : : : : : :73's de Edd : : : : : I always wanted to be a procrastinator, but I just never got around to it. : : : :  : : : |
:
:
:
:
::You won’t get anything at 455KC with the IF being so far off. Turn the attenuator up on the signal generator, then adjust the 2nd IF first. Then the first. When you start getting a signal though, turn the attenuation back down.
::
::
:
:
:
:
Well tried as you suggested, had to start where I got a signal at 640, then kept turning the generator down about 10 kz at a time then adjusted the IF's till the signal came thru , kept doing that till I got down to about 590 and ran out of adjustment on the IF screws. but it did make a difference on the dial readings they are closer to where they should be. the high end my local station at 1440 is now at 1520 espn 1000 tunes in at 1100 alot closer than before . I must have a mica or something out to prevent the IF's from resonating at 455... guess I will start subing caps.
::
::
:Well tried as you suggested, had to start where I got a signal at 640, then kept turning the generator down about 10 kz at a time then adjusted the IF's till the signal came thru , kept doing that till I got down to about 590 and ran out of adjustment on the IF screws. but it did make a difference on the dial readings they are closer to where they should be. the high end my local station at 1440 is now at 1520 espn 1000 tunes in at 1100 alot closer than before . I must have a mica or something out to prevent the IF's from resonating at 455... guess I will start subing caps.
:
Hi Elton,
Can you get the second IF to tune to 455? There has to be something not right inside an IF can to cause that.
As a bizaar possibility the IF tube could have high plate to supressor grid capacitance. That is a really weird failure for a tube, though. If you have another IF tube you may want to try it, but I wouldn't order a tube for that reason because it is such an odd failure.
Best Regards,
Bill Grimm
:::
:::
::Well tried as you suggested, had to start where I got a signal at 640, then kept turning the generator down about 10 kz at a time then adjusted the IF's till the signal came thru , kept doing that till I got down to about 590 and ran out of adjustment on the IF screws. but it did make a difference on the dial readings they are closer to where they should be. the high end my local station at 1440 is now at 1520 espn 1000 tunes in at 1100 alot closer than before . I must have a mica or something out to prevent the IF's from resonating at 455... guess I will start subing caps.
::
:Hi Elton,
: Can you get the second IF to tune to 455? There has to be something not right inside an IF can to cause that.
: As a bizaar possibility the IF tube could have high plate to supressor grid capacitance. That is a really weird failure for a tube, though. If you have another IF tube you may want to try it, but I wouldn't order a tube for that reason because it is such an odd failure.
:
:Best Regards,
:
:Bill Grimm
:
I had to solder-blob an open litz wire coil once and it drastically detuned the coil. The blob repair effectively changed the length/distributed capacitance of the winding.
If your coil wire is solid wire, it should do OK.
Would adding or subtracting to the length of the coil winding help bring it back into band tune?
- Walter.
:::
:::
::Well tried as you suggested, had to start where I got a signal at 640, then kept turning the generator down about 10 kz at a time then adjusted the IF's till the signal came thru , kept doing that till I got down to about 590 and ran out of adjustment on the IF screws. but it did make a difference on the dial readings they are closer to where they should be. the high end my local station at 1440 is now at 1520 espn 1000 tunes in at 1100 alot closer than before . I must have a mica or something out to prevent the IF's from resonating at 455... guess I will start subing caps.
::
:Hi Elton,
: Can you get the second IF to tune to 455? There has to be something not right inside an IF can to cause that.
: As a bizaar possibility the IF tube could have high plate to supressor grid capacitance. That is a really weird failure for a tube, though. If you have another IF tube you may want to try it, but I wouldn't order a tube for that reason because it is such an odd failure.
:
:Best Regards,
:
:Bill Grimm
:
Hi Bill, Yes I don't get it either never came across anything like this before, if I set the generator to 455 and inject to the grid of the converter tube, I can tune the volume all the way up and rock the screws on the cans all the way to either end , and wont get a thing , but if I rock the dial on my generator the signal shows up at 640 on my generator, as I said in a earlier post tried to walk the signal down to 455 on the radio but not enough adjustment in the can to allow it. I did have a broken wire on the coil , but only took a 1/4 inch piece to complete the circuit , don't think would throw off the radio that much?
E.
::::
::::
:::Well tried as you suggested, had to start where I got a signal at 640, then kept turning the generator down about 10 kz at a time then adjusted the IF's till the signal came thru , kept doing that till I got down to about 590 and ran out of adjustment on the IF screws. but it did make a difference on the dial readings they are closer to where they should be. the high end my local station at 1440 is now at 1520 espn 1000 tunes in at 1100 alot closer than before . I must have a mica or something out to prevent the IF's from resonating at 455... guess I will start subing caps.
:::
::Hi Elton,
:: Can you get the second IF to tune to 455? There has to be something not right inside an IF can to cause that.
:: As a bizaar possibility the IF tube could have high plate to supressor grid capacitance. That is a really weird failure for a tube, though. If you have another IF tube you may want to try it, but I wouldn't order a tube for that reason because it is such an odd failure.
::
::Best Regards,
::
::Bill Grimm
::
:Hi Bill, Yes I don't get it either never came across anything like this before, if I set the generator to 455 and inject to the grid of the converter tube, I can tune the volume all the way up and rock the screws on the cans all the way to either end , and wont get a thing , but if I rock the dial on my generator the signal shows up at 640 on my generator, as I said in a earlier post tried to walk the signal down to 455 on the radio but not enough adjustment in the can to allow it. I did have a broken wire on the coil , but only took a 1/4 inch piece to complete the circuit , don't think would throw off the radio that much?
:E.
:
Hi Elton,
Your oscillator coil isn't the problem with you IF being off. The signal is injected after the oscillator. 640KHz is seriously abnormal for an IF and both IF cans being off like this seems very unlikely. How sure are you of the signal generator's calibration. Both IF cans being unable to tune down to 455 seems very suspicious.
Best Regards,
Bill Grimm
:::::
:::::
::::Well tried as you suggested, had to start where I got a signal at 640, then kept turning the generator down about 10 kz at a time then adjusted the IF's till the signal came thru , kept doing that till I got down to about 590 and ran out of adjustment on the IF screws. but it did make a difference on the dial readings they are closer to where they should be. the high end my local station at 1440 is now at 1520 espn 1000 tunes in at 1100 alot closer than before . I must have a mica or something out to prevent the IF's from resonating at 455... guess I will start subing caps.
::::
:::Hi Elton,
::: Can you get the second IF to tune to 455? There has to be something not right inside an IF can to cause that.
::: As a bizaar possibility the IF tube could have high plate to supressor grid capacitance. That is a really weird failure for a tube, though. If you have another IF tube you may want to try it, but I wouldn't order a tube for that reason because it is such an odd failure.
:::
:::Best Regards,
:::
:::Bill Grimm
:::
::Hi Bill, Yes I don't get it either never came across anything like this before, if I set the generator to 455 and inject to the grid of the converter tube, I can tune the volume all the way up and rock the screws on the cans all the way to either end , and wont get a thing , but if I rock the dial on my generator the signal shows up at 640 on my generator, as I said in a earlier post tried to walk the signal down to 455 on the radio but not enough adjustment in the can to allow it. I did have a broken wire on the coil , but only took a 1/4 inch piece to complete the circuit , don't think would throw off the radio that much?
::E.
::
:Hi Elton,
: Your oscillator coil isn't the problem with you IF being off. The signal is injected after the oscillator. 640KHz is seriously abnormal for an IF and both IF cans being off like this seems very unlikely. How sure are you of the signal generator's calibration. Both IF cans being unable to tune down to 455 seems very suspicious.
:
:Best Regards,
:
:Bill Grimm
:
Bill, I have checked my generator with my digital SW radio and it is only off about 5hz which 455 is really around 460. This radio was thrown out to the road and has sat in my basement for about 5 years, just decided to see if I could get it going again. the varible cap has rust on the adjustment nuts , so I know I could not turn them even if I wanted to. but this radio had no reception at all but found it was due to the coil having a broken wire, Who's to say that someone had not fiddled with the cans . is there a alternative to try and get these cans at 455 can I inject directly into the cans? Thanks
::::::
::::::
:::::Well tried as you suggested, had to start where I got a signal at 640, then kept turning the generator down about 10 kz at a time then adjusted the IF's till the signal came thru , kept doing that till I got down to about 590 and ran out of adjustment on the IF screws. but it did make a difference on the dial readings they are closer to where they should be. the high end my local station at 1440 is now at 1520 espn 1000 tunes in at 1100 alot closer than before . I must have a mica or something out to prevent the IF's from resonating at 455... guess I will start subing caps.
:::::
::::Hi Elton,
:::: Can you get the second IF to tune to 455? There has to be something not right inside an IF can to cause that.
:::: As a bizaar possibility the IF tube could have high plate to supressor grid capacitance. That is a really weird failure for a tube, though. If you have another IF tube you may want to try it, but I wouldn't order a tube for that reason because it is such an odd failure.
::::
::::Best Regards,
::::
::::Bill Grimm
::::
:::Hi Bill, Yes I don't get it either never came across anything like this before, if I set the generator to 455 and inject to the grid of the converter tube, I can tune the volume all the way up and rock the screws on the cans all the way to either end , and wont get a thing , but if I rock the dial on my generator the signal shows up at 640 on my generator, as I said in a earlier post tried to walk the signal down to 455 on the radio but not enough adjustment in the can to allow it. I did have a broken wire on the coil , but only took a 1/4 inch piece to complete the circuit , don't think would throw off the radio that much?
:::E.
:::
::Hi Elton,
:: Your oscillator coil isn't the problem with you IF being off. The signal is injected after the oscillator. 640KHz is seriously abnormal for an IF and both IF cans being off like this seems very unlikely. How sure are you of the signal generator's calibration. Both IF cans being unable to tune down to 455 seems very suspicious.
::
::Best Regards,
::
::Bill Grimm
::
:Bill, I have checked my generator with my digital SW radio and it is only off about 5hz which 455 is really around 460. This radio was thrown out to the road and has sat in my basement for about 5 years, just decided to see if I could get it going again. the varible cap has rust on the adjustment nuts , so I know I could not turn them even if I wanted to. but this radio had no reception at all but found it was due to the coil having a broken wire, Who's to say that someone had not fiddled with the cans . is there a alternative to try and get these cans at 455 can I inject directly into the cans? Thanks
:
Well guys I have decided to start over from scratch, I hooked up the sig gen at the grid of the 7B8 set the dial of the radio at 600 khz, and no antenna. started with backing the IF screws out about half way on each can , then started with 2nd can and turned them out a little and started getting static next thing I know I am picking up my local radio station at 790 KHZ ?? without a antenna? can IF's tune that far from 455?
You mentioned rust on the IF tuning caps. It seems to me that you may have corrosion decreasing the capacitance on the tuning. If that is the case you will need to clean up the capacitors or replace the IFs.
Corrosion is often a problem in Loctal tube sockets. That may be another possibility.
Best Regards,
Bill Grimm
73's de Edd
|
:Hi Elton,
: You mentioned rust on the IF tuning caps. It seems to me that you may have corrosion decreasing the capacitance on the tuning. If that is the case you will need to clean up the capacitors or replace the IFs.
: Corrosion is often a problem in Loctal tube sockets. That may be another possibility.
:
:Best Regards,
:
:Bill Grimm
:
:
:
: : : : : : : : : : : :Sir Elton . . . . . : : :I‘se . . . . . b a a a a a ck : : :Some reason or another, seems like that there is not enough inductance or not enough capacitance in the IF transformer(s) to pull the IF resonance on down to 455. : : :The most critical resonant pair of the TWO I.F. transformers available four sets of “ winding and adjustable trimmer capacitor “ involved, is the one that is off the plate of the mixer. The tuned sets trailing, then just enhance the overall amplitude of I.F. signal at that frequency, with broadness of tuning diminishing on down the alignment line. : : :Lets crunch some numbers in an evaluation, considering that the winding of that inductor/variable capacitor of that set is going to be a fixed constant , let’s use 1020 microhenry as its value. If one then sets a mica trimmer capacitor to being compressed up to ~ ¾ of its attainable max capacitance value, that will throw in ~120pf of capacitance and effect a resonance of the pair of ~ 455 Kc. :Now that is ideally, what we are looking for, but what you are EXPERIENCING, is 670 Kc, so that would be reflective of that existing L-C resonant circuit having only a capacitive value of 55 pf, present to work with that fixed 1020uh winding. : : :Now another aspect to consider would be the variance of the inductance factor, but that would require a dropping of the inductance on down to a reduced value of a whopping ~476 uh in order to create that tuning resonance of 670 Kc. : : :NOT gonna hoppen ! : : :NowI can't eyeball the wire inside of that/those I.F. transformers , to see whether the wire beig used is common 35-38 ga single or double coton covered enamelled wire OR being Litz wire. : : : If its Litz, and taking 10/46 as the norm . . . and that would consist of 10 separate strands of #46 enamelled wire clustered together and loosely twisted as a single wire and then overwound with its cotton insulator(s) covering. : : :What I have seen happen on LITZ wire is the time related action of a chemical contaminant in eroding away individual strands , at a solder junction, thereby decreasing the effective inductance of the winding. :This was most common back at prodiction time in the erroneous cross utilization of a soldering iron that STILL had contamination of ACID flux on it from a counter chassis operation in mechanical soldering . : : :As individual conductors are eaten out of circuit , the effective inductance of the wound coil drops and frequency rises. : : :As a fix, one rosin fluxes and resolders the ends of the LITZ wire to get all conductors in circuit again. : : :BUT THIS could not account for the whopping 500+ uh involved here. . . . . only a 10 uh or so, if only hanging on by one strand. :About the only way to evaluate for LITZ presence in the coil winding is to peel back enough cotton overwrap, aside, as to then be able to see if there is a single wire or MULTIPLE fine wires. : : :Now considering that the fault is with low trimmer capacitance, how about working with the 1st IF transformer and padding in ~two ~47 / 50 pf fixed silver mica units . . . even ceramics in a pinch . . .to :see if the unit will tune in closer to 455Kc. : : :Also take that tip of disabling the local oscillator while aligning. : : :If this works, then the question is to be figured out as to the loss of available total capacitance of the trimmers. I couldn't even see severe salt water corrosion / rust ? deposits on ALL of the individual leaves of a trimmer, in limiting its max available capacitance down that much . : : :Work on that . . . . . : : : : : : 73's de Edd : : : : : Now I ask you . . . . is it all right for vegetarians to eat animal crackers ?. : :Thanks Edd , Finally got the IF's to resonate at 455 I pulled them out and they were full of crud and dust , basicly I gave them a bath in contact cleaner and did check for bad conections , put it back together and it took me awahile but finally got them tuned in! BUT I still have the problem with the J and F padders, the lower half of the dial will line up great with the J padder, but higher than 900 khz the dial takes on a sort of band spread the higher it goes the worst being 1250 station coming in at 1400 and the F padder screw is out all the way , I have been checking everthing around the osc coil but nothing out of the ordinary. I found out this is a chassis 6A05R and the schematic shows the C2 cap as connecting to the third wire of the ac cord??? is this radio suppose to have a grounded ac cord?, my C2 is just connected to the antenna coil and the other end is not going anywhere. Thanks Elton : : : : : |
:
:
:
:
:
::Hi Elton,
:: You mentioned rust on the IF tuning caps. It seems to me that you may have corrosion decreasing the capacitance on the tuning. If that is the case you will need to clean up the capacitors or replace the IFs.
:: Corrosion is often a problem in Loctal tube sockets. That may be another possibility.
::
::Best Regards,
::
::Bill Grimm
::
:
:
You say: 73's de Edd |
::
::
::
::
::
::
::
::
::
::
::
::
::
::
::Sir Elton . . . . .
::
::
::I‘se . . . . . b a a a a a ck
::
::
::Some reason or another, seems like that there is not enough inductance or not enough capacitance in the IF transformer(s) to pull the IF resonance on down to 455.
::
::
::The most critical resonant pair of the TWO I.F. transformers available four sets of “ winding and adjustable trimmer capacitor “ involved, is the one that is off the plate of the mixer. The tuned sets trailing, then just enhance the overall amplitude of I.F. signal at that frequency, with broadness of tuning diminishing on down the alignment line.
::
::
::Lets crunch some numbers in an evaluation, considering that the winding of that inductor/variable capacitor of that set is going to be a fixed constant , let’s use 1020 microhenry as its value. If one then sets a mica trimmer capacitor to being compressed up to ~ ¾ of its attainable max capacitance value, that will throw in ~120pf of capacitance and effect a resonance of the pair of ~ 455 Kc.
::Now that is ideally, what we are looking for, but what you are EXPERIENCING, is 670 Kc, so that would be reflective of that existing L-C resonant circuit having only a capacitive value of 55 pf, present to work with that fixed 1020uh winding.
::
::
::Now another aspect to consider would be the variance of the inductance factor, but that would require a dropping of the inductance on down to a reduced value of a whopping ~476 uh in order to create that tuning resonance of 670 Kc.
::
::
::NOT gonna hoppen !
::
::
::NowI can't eyeball the wire inside of that/those I.F. transformers , to see whether the wire beig used is common 35-38 ga single or double coton covered enamelled wire OR being Litz wire.
::
::
:: If its Litz, and taking 10/46 as the norm . . . and that would consist of 10 separate strands of #46 enamelled wire clustered together and loosely twisted as a single wire and then overwound with its cotton insulator(s) covering.
::
::
::What I have seen happen on LITZ wire is the time related action of a chemical contaminant in eroding away individual strands , at a solder junction, thereby decreasing the effective inductance of the winding.
::This was most common back at prodiction time in the erroneous cross utilization of a soldering iron that STILL had contamination of ACID flux on it from a counter chassis operation in mechanical soldering .
::
::
::As individual conductors are eaten out of circuit , the effective inductance of the wound coil drops and frequency rises.
::
::
::As a fix, one rosin fluxes and resolders the ends of the LITZ wire to get all conductors in circuit again.
::
::
::BUT THIS could not account for the whopping 500+ uh involved here. . . . . only a 10 uh or so, if only hanging on by one strand.
::About the only way to evaluate for LITZ presence in the coil winding is to peel back enough cotton overwrap, aside, as to then be able to see if there is a single wire or MULTIPLE fine wires.
::
::
::Now considering that the fault is with low trimmer capacitance, how about working with the 1st IF transformer and padding in ~two ~47 / 50 pf fixed silver mica units . . . even ceramics in a pinch . . .to
::see if the unit will tune in closer to 455Kc.
::
::
::Also take that tip of disabling the local oscillator while aligning.
::
::
::If this works, then the question is to be figured out as to the loss of available total capacitance of the trimmers. I couldn't even see severe salt water corrosion / rust ? deposits on ALL of the individual leaves of a trimmer, in limiting its max available capacitance down that much .
::
::
::Work on that . . . . .
::
::
::
::
::
:: 73's de Edd
::
::
::
::
:: Now I ask you . . . . is it all right for vegetarians to eat animal crackers ?.
::
::Thanks Edd , Finally got the IF's to resonate at 455 I pulled them out and they were full of crud and dust , basicly I gave them a bath in contact cleaner and did check for bad conections , put it back together and it took me awahile but finally got them tuned in! BUT I still have the problem with the J and F padders, the lower half of the dial will line up great with the J padder, but higher than 900 khz the dial takes on a sort of band spread the higher it goes the worst being 1250 station coming in at 1400 and the F padder screw is out all the way , I have been checking everthing around the osc coil but nothing out of the ordinary. I found out this is a chassis 6A05R and the schematic shows the C2 cap as connecting to the third wire of the ac cord??? is this radio suppose to have a grounded ac cord?, my C2 is just connected to the antenna coil and the other end is not going anywhere.
:Thanks
:Elton
::
::
::
::
::
::
::
::
::
::
:::Hi Elton,
::: You mentioned rust on the IF tuning caps. It seems to me that you may have corrosion decreasing the capacitance on the tuning. If that is the case you will need to clean up the capacitors or replace the IFs.
::: Corrosion is often a problem in Loctal tube sockets. That may be another possibility.
:::
:::Best Regards,
:::
:::Bill Grimm
:::
::
::
:
:
:
: : : : : : : : : : : :Sir Elton . . . . . : : : :You say: : : : : . . . . .but higher than 900 khz the dial takes on a sort of band spread the higher it goes the worst being 1250 station coming in at 1400 and the F padder screw is out all the way , I have been checking everthing around the osc coil but nothing out of the ordinary. : : : :If I read this as a 1250Khz station coming in at 1400 on the dial scale, then the situation is now that of the F padder being in need of a slow tightening up /compressing up a bit. With the then total effective maximum capacitance value of the tuning condenser at that end of the dial scale, then being increased a bit. : : :This should then eventually /progressively lower the dial scale positioning of this 1250 station to slowly being "walked" on down to 1250 on the dial scale. : : : 73's de Edd : : : : : People will believe anything . . . . . if you just whisper it. : :Hi edd, tightening up the screw makes it spread out farther it puts 1250 above 1600 Elton : : : : : |
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::: ::: ::: ::: ::: ::: ::: ::: ::: ::: ::: :::Sir Elton . . . . . ::: ::: :::I‘se . . . . . b a a a a a ck ::: ::: :::Some reason or another, seems like that there is not enough inductance or not enough capacitance in the IF transformer(s) to pull the IF resonance on down to 455. ::: ::: :::The most critical resonant pair of the TWO I.F. transformers available four sets of “ winding and adjustable trimmer capacitor “ involved, is the one that is off the plate of the mixer. The tuned sets trailing, then just enhance the overall amplitude of I.F. signal at that frequency, with broadness of tuning diminishing on down the alignment line. ::: ::: :::Lets crunch some numbers in an evaluation, considering that the winding of that inductor/variable capacitor of that set is going to be a fixed constant , let’s use 1020 microhenry as its value. If one then sets a mica trimmer capacitor to being compressed up to ~ ¾ of its attainable max capacitance value, that will throw in ~120pf of capacitance and effect a resonance of the pair of ~ 455 Kc. :::Now that is ideally, what we are looking for, but what you are EXPERIENCING, is 670 Kc, so that would be reflective of that existing L-C resonant circuit having only a capacitive value of 55 pf, present to work with that fixed 1020uh winding. ::: ::: :::Now another aspect to consider would be the variance of the inductance factor, but that would require a dropping of the inductance on down to a reduced value of a whopping ~476 uh in order to create that tuning resonance of 670 Kc. ::: ::: :::NOT gonna hoppen ! ::: ::: :::NowI can't eyeball the wire inside of that/those I.F. transformers , to see whether the wire beig used is common 35-38 ga single or double coton covered enamelled wire OR being Litz wire. ::: ::: ::: If its Litz, and taking 10/46 as the norm . . . and that would consist of 10 separate strands of #46 enamelled wire clustered together and loosely twisted as a single wire and then overwound with its cotton insulator(s) covering. ::: ::: :::What I have seen happen on LITZ wire is the time related action of a chemical contaminant in eroding away individual strands , at a solder junction, thereby decreasing the effective inductance of the winding. :::This was most common back at prodiction time in the erroneous cross utilization of a soldering iron that STILL had contamination of ACID flux on it from a counter chassis operation in mechanical soldering . ::: ::: :::As individual conductors are eaten out of circuit , the effective inductance of the wound coil drops and frequency rises. ::: ::: :::As a fix, one rosin fluxes and resolders the ends of the LITZ wire to get all conductors in circuit again. ::: ::: :::BUT THIS could not account for the whopping 500+ uh involved here. . . . . only a 10 uh or so, if only hanging on by one strand. :::About the only way to evaluate for LITZ presence in the coil winding is to peel back enough cotton overwrap, aside, as to then be able to see if there is a single wire or MULTIPLE fine wires. ::: ::: :::Now considering that the fault is with low trimmer capacitance, how about working with the 1st IF transformer and padding in ~two ~47 / 50 pf fixed silver mica units . . . even ceramics in a pinch . . .to :::see if the unit will tune in closer to 455Kc. ::: ::: :::Also take that tip of disabling the local oscillator while aligning. ::: ::: :::If this works, then the question is to be figured out as to the loss of available total capacitance of the trimmers. I couldn't even see severe salt water corrosion / rust ? deposits on ALL of the individual leaves of a trimmer, in limiting its max available capacitance down that much . ::: ::: :::Work on that . . . . . ::: ::: ::: ::: ::: ::: 73's de Edd ::: ::: ::: ::: ::: Now I ask you . . . . is it all right for vegetarians to eat animal crackers ?. ::: :::Thanks Edd , Finally got the IF's to resonate at 455 I pulled them out and they were full of crud and dust , basicly I gave them a bath in contact cleaner and did check for bad conections , put it back together and it took me awahile but finally got them tuned in! BUT I still have the problem with the J and F padders, the lower half of the dial will line up great with the J padder, but higher than 900 khz the dial takes on a sort of band spread the higher it goes the worst being 1250 station coming in at 1400 and the F padder screw is out all the way , I have been checking everthing around the osc coil but nothing out of the ordinary. I found out this is a chassis 6A05R and the schematic shows the C2 cap as connecting to the third wire of the ac cord??? is this radio suppose to have a grounded ac cord?, my C2 is just connected to the antenna coil and the other end is not going anywhere. ::Thanks ::Elton ::: ::: ::: ::: ::: |
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::::Hi Elton,
:::: You mentioned rust on the IF tuning caps. It seems to me that you may have corrosion decreasing the capacitance on the tuning. If that is the case you will need to clean up the capacitors or replace the IFs.
:::: Corrosion is often a problem in Loctal tube sockets. That may be another possibility.
::::
::::Best Regards,
::::
::::Bill Grimm
::::
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:
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:: :: :: :: :: :: :: :: :: :: :: ::Sir Elton . . . . . :: :: :: ::You say: :: :: :: :: . . . . .but higher than 900 khz the dial takes on a sort of band spread the higher it goes the worst being 1250 station coming in at 1400 and the F padder screw is out all the way , I have been checking everthing around the osc coil but nothing out of the ordinary. :: :: :: ::If I read this as a 1250Khz station coming in at 1400 on the dial scale, then the situation is now that of the F padder being in need of a slow tightening up /compressing up a bit. With the then total effective maximum capacitance value of the tuning condenser at that end of the dial scale, then being increased a bit. :: :: ::This should then eventually /progressively lower the dial scale positioning of this 1250 station to slowly being "walked" on down to 1250 on the dial scale. :: :: :: 73's de Edd :: :: :: :: :: People will believe anything . . . . . if you just whisper it. :: ::Hi edd, tightening up the screw makes it spread out farther it puts 1250 above 1600 :Elton :: :: :: :: :: |
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:::: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: ::::Sir Elton . . . . . :::: :::: ::::I‘se . . . . . b a a a a a ck :::: :::: ::::Some reason or another, seems like that there is not enough inductance or not enough capacitance in the IF transformer(s) to pull the IF resonance on down to 455. :::: :::: ::::The most critical resonant pair of the TWO I.F. transformers available four sets of “ winding and adjustable trimmer capacitor “ involved, is the one that is off the plate of the mixer. The tuned sets trailing, then just enhance the overall amplitude of I.F. signal at that frequency, with broadness of tuning diminishing on down the alignment line. :::: :::: ::::Lets crunch some numbers in an evaluation, considering that the winding of that inductor/variable capacitor of that set is going to be a fixed constant , let’s use 1020 microhenry as its value. If one then sets a mica trimmer capacitor to being compressed up to ~ ¾ of its attainable max capacitance value, that will throw in ~120pf of capacitance and effect a resonance of the pair of ~ 455 Kc. ::::Now that is ideally, what we are looking for, but what you are EXPERIENCING, is 670 Kc, so that would be reflective of that existing L-C resonant circuit having only a capacitive value of 55 pf, present to work with that fixed 1020uh winding. :::: :::: ::::Now another aspect to consider would be the variance of the inductance factor, but that would require a dropping of the inductance on down to a reduced value of a whopping ~476 uh in order to create that tuning resonance of 670 Kc. :::: :::: ::::NOT gonna hoppen ! :::: :::: ::::NowI can't eyeball the wire inside of that/those I.F. transformers , to see whether the wire beig used is common 35-38 ga single or double coton covered enamelled wire OR being Litz wire. :::: :::: :::: If its Litz, and taking 10/46 as the norm . . . and that would consist of 10 separate strands of #46 enamelled wire clustered together and loosely twisted as a single wire and then overwound with its cotton insulator(s) covering. :::: :::: ::::What I have seen happen on LITZ wire is the time related action of a chemical contaminant in eroding away individual strands , at a solder junction, thereby decreasing the effective inductance of the winding. ::::This was most common back at prodiction time in the erroneous cross utilization of a soldering iron that STILL had contamination of ACID flux on it from a counter chassis operation in mechanical soldering . :::: :::: ::::As individual conductors are eaten out of circuit , the effective inductance of the wound coil drops and frequency rises. :::: :::: ::::As a fix, one rosin fluxes and resolders the ends of the LITZ wire to get all conductors in circuit again. :::: :::: ::::BUT THIS could not account for the whopping 500+ uh involved here. . . . . only a 10 uh or so, if only hanging on by one strand. ::::About the only way to evaluate for LITZ presence in the coil winding is to peel back enough cotton overwrap, aside, as to then be able to see if there is a single wire or MULTIPLE fine wires. :::: :::: ::::Now considering that the fault is with low trimmer capacitance, how about working with the 1st IF transformer and padding in ~two ~47 / 50 pf fixed silver mica units . . . even ceramics in a pinch . . .to ::::see if the unit will tune in closer to 455Kc. :::: :::: ::::Also take that tip of disabling the local oscillator while aligning. :::: :::: ::::If this works, then the question is to be figured out as to the loss of available total capacitance of the trimmers. I couldn't even see severe salt water corrosion / rust ? deposits on ALL of the individual leaves of a trimmer, in limiting its max available capacitance down that much . :::: :::: ::::Work on that . . . . . :::: :::: :::: :::: :::: :::: 73's de Edd :::: :::: :::: :::: :::: Now I ask you . . . . is it all right for vegetarians to eat animal crackers ?. :::: ::::Thanks Edd , Finally got the IF's to resonate at 455 I pulled them out and they were full of crud and dust , basicly I gave them a bath in contact cleaner and did check for bad conections , put it back together and it took me awahile but finally got them tuned in! BUT I still have the problem with the J and F padders, the lower half of the dial will line up great with the J padder, but higher than 900 khz the dial takes on a sort of band spread the higher it goes the worst being 1250 station coming in at 1400 and the F padder screw is out all the way , I have been checking everthing around the osc coil but nothing out of the ordinary. I found out this is a chassis 6A05R and the schematic shows the C2 cap as connecting to the third wire of the ac cord??? is this radio suppose to have a grounded ac cord?, my C2 is just connected to the antenna coil and the other end is not going anywhere. :::Thanks :::Elton :::: :::: :::: :::: :::: |
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::::
::::
::::
::::
:::::Hi Elton,
::::: You mentioned rust on the IF tuning caps. It seems to me that you may have corrosion decreasing the capacitance on the tuning. If that is the case you will need to clean up the capacitors or replace the IFs.
::::: Corrosion is often a problem in Loctal tube sockets. That may be another possibility.
:::::
:::::Best Regards,
:::::
:::::Bill Grimm
:::::
::::
::::
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:::
::
::
:
:
Edd your last post about increasing the capacitence got me thinking , I had to repair the osc coil because of a break on it , I only used a small strand of wire about 3/8 of inch to jump the gap, so started experimenting with caps across the osc coil and lo and behold .05 shifted the whole upper half of the dial , even the F padder will now adjust all the way to 1600! Could that small repair to the osc coil have caused the whole coil to shift? I guess I dont understand how it could.
Elton
Clifton
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:::Sir Elton . . . . .
:::
:::
:::
:::You say:
:::
:::
:::
::: . . . . .but higher than 900 khz the dial takes on a sort of band spread the higher it goes the worst being 1250 station coming in at 1400 and the F padder screw is out all the way , I have been checking everthing around the osc coil but nothing out of the ordinary.
:::
:::
:::
:::If I read this as a 1250Khz station coming in at 1400 on the dial scale, then the situation is now that of the F padder being in need of a slow tightening up /compressing up a bit. With the then total effective maximum capacitance value of the tuning condenser at that end of the dial scale, then being increased a bit.
:::
:::
:::This should then eventually /progressively lower the dial scale positioning of this 1250 station to slowly being "walked" on down to 1250 on the dial scale.
:::
:::
::: 73's de Edd
:::
:::
:::
:::
::: People will believe anything . . . . . if you just whisper it.
:::
:::Hi edd, tightening up the screw makes it spread out farther it puts 1250 above 1600
::Elton
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:::::Sir Elton . . . . .
:::::
:::::
:::::I‘se . . . . . b a a a a a ck
:::::
:::::
:::::Some reason or another, seems like that there is not enough inductance or not enough capacitance in the IF transformer(s) to pull the IF resonance on down to 455.
:::::
:::::
:::::The most critical resonant pair of the TWO I.F. transformers available four sets of “ winding and adjustable trimmer capacitor “ involved, is the one that is off the plate of the mixer. The tuned sets trailing, then just enhance the overall amplitude of I.F. signal at that frequency, with broadness of tuning diminishing on down the alignment line.
:::::
:::::
:::::Lets crunch some numbers in an evaluation, considering that the winding of that inductor/variable capacitor of that set is going to be a fixed constant , let’s use 1020 microhenry as its value. If one then sets a mica trimmer capacitor to being compressed up to ~ ¾ of its attainable max capacitance value, that will throw in ~120pf of capacitance and effect a resonance of the pair of ~ 455 Kc.
:::::Now that is ideally, what we are looking for, but what you are EXPERIENCING, is 670 Kc, so that would be reflective of that existing L-C resonant circuit having only a capacitive value of 55 pf, present to work with that fixed 1020uh winding.
:::::
:::::
:::::Now another aspect to consider would be the variance of the inductance factor, but that would require a dropping of the inductance on down to a reduced value of a whopping ~476 uh in order to create that tuning resonance of 670 Kc.
:::::
:::::
:::::NOT gonna hoppen !
:::::
:::::
:::::NowI can't eyeball the wire inside of that/those I.F. transformers , to see whether the wire beig used is common 35-38 ga single or double coton covered enamelled wire OR being Litz wire.
:::::
:::::
::::: If its Litz, and taking 10/46 as the norm . . . and that would consist of 10 separate strands of #46 enamelled wire clustered together and loosely twisted as a single wire and then overwound with its cotton insulator(s) covering.
:::::
:::::
:::::What I have seen happen on LITZ wire is the time related action of a chemical contaminant in eroding away individual strands , at a solder junction, thereby decreasing the effective inductance of the winding.
:::::This was most common back at prodiction time in the erroneous cross utilization of a soldering iron that STILL had contamination of ACID flux on it from a counter chassis operation in mechanical soldering .
:::::
:::::
:::::As individual conductors are eaten out of circuit , the effective inductance of the wound coil drops and frequency rises.
:::::
:::::
:::::As a fix, one rosin fluxes and resolders the ends of the LITZ wire to get all conductors in circuit again.
:::::
:::::
:::::BUT THIS could not account for the whopping 500+ uh involved here. . . . . only a 10 uh or so, if only hanging on by one strand.
:::::About the only way to evaluate for LITZ presence in the coil winding is to peel back enough cotton overwrap, aside, as to then be able to see if there is a single wire or MULTIPLE fine wires.
:::::
:::::
:::::Now considering that the fault is with low trimmer capacitance, how about working with the 1st IF transformer and padding in ~two ~47 / 50 pf fixed silver mica units . . . even ceramics in a pinch . . .to
:::::see if the unit will tune in closer to 455Kc.
:::::
:::::
:::::Also take that tip of disabling the local oscillator while aligning.
:::::
:::::
:::::If this works, then the question is to be figured out as to the loss of available total capacitance of the trimmers. I couldn't even see severe salt water corrosion / rust ? deposits on ALL of the individual leaves of a trimmer, in limiting its max available capacitance down that much .
:::::
:::::
:::::Work on that . . . . .
:::::
:::::
:::::
:::::
:::::
::::: 73's de Edd
:::::
:::::
:::::
:::::
::::: Now I ask you . . . . is it all right for vegetarians to eat animal crackers ?.
:::::
:::::Thanks Edd , Finally got the IF's to resonate at 455 I pulled them out and they were full of crud and dust , basicly I gave them a bath in contact cleaner and did check for bad conections , put it back together and it took me awahile but finally got them tuned in! BUT I still have the problem with the J and F padders, the lower half of the dial will line up great with the J padder, but higher than 900 khz the dial takes on a sort of band spread the higher it goes the worst being 1250 station coming in at 1400 and the F padder screw is out all the way , I have been checking everthing around the osc coil but nothing out of the ordinary. I found out this is a chassis 6A05R and the schematic shows the C2 cap as connecting to the third wire of the ac cord??? is this radio suppose to have a grounded ac cord?, my C2 is just connected to the antenna coil and the other end is not going anywhere.
::::Thanks
::::Elton
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
::::::Hi Elton,
:::::: You mentioned rust on the IF tuning caps. It seems to me that you may have corrosion decreasing the capacitance on the tuning. If that is the case you will need to clean up the capacitors or replace the IFs.
:::::: Corrosion is often a problem in Loctal tube sockets. That may be another possibility.
::::::
::::::Best Regards,
::::::
::::::Bill Grimm
::::::
:::::
:::::
::::
::::
:::
:::
::
::
:Edd your last post about increasing the capacitence got me thinking , I had to repair the osc coil because of a break on it , I only used a small strand of wire about 3/8 of inch to jump the gap, so started experimenting with caps across the osc coil and lo and behold .05 shifted the whole upper half of the dial , even the F padder will now adjust all the way to 1600! Could that small repair to the osc coil have caused the whole coil to shift? I guess I dont understand how it could.
:Elton
:
Don't think that you have any problem with your repair method of the osc coil at these low AM frequencies . . . .attempting in the osc section of an FM band receiver. . . Yes. 73's de Edd |