Don, OK, understand what you mean by “L3 serve both bands” but that cannot explain why either coil cannot be tuned properly to the low frequency alignment value.

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Jacques Are you sure you are looking at an S-85?? I see no indication of cores in the RF tuning ?for bands 1,2 ?.

Note Bands go 1,2,3,4? up in frequency, but coil numbers go the other way.. gets us all!?

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Re ???Is it just me, or the two lower band inductors are connected in reverse (one for each other) in the S85 schematic ???

Do you mean L3? which serves both bands ? ?IF so we have gone on wild trips about that. I finally drew the switch wafer in all positions, It is somewhere.

It is too hard to spell it out, without a picture

/g/HallicraftersRadios/message/31639?? ?I drew this just to find out the ground switch stuff while the you need to keep the coils in hand 2.

I could not rotate this switch in my head.

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Emanuele ???

Re ??Here is what I get:?

Band 1: main tune dial at 0.54MHz - the bottom of band 1 (C7A fully meshed - maximum capacity)

ref only.I shriveled it..don

The peak is a little below 500KHz (in fact not visible) - C4 has no visible effects.

Turning the main dial toward higher frequencies, I see the peak moving right.

At the end:

Good you did all this work. ?I guess you did not verify 600Kcs? but used 540 kcs on the dial and here it is actually peaking a 500 or just under. That is 8 % off, and ??

that is a very sharp? peak so RF tuning alignment need to track exactly…? and does not .. a confirmation of what you said all along

the trimmer will be dwarfed by the Main cap so you will be stuck with what you got [for now]

I have assumed you know all about calculating capacitors in parallel etc, but you have said little about that.

If for some reason L3 is too high [ not that simple but..] by that 8% ?and manage to lower it, then at 1400? [actually 1200?? Forget now] things should shift up by 8% but that isn’t ??near enough.

The trimmer seems to work ?but it is hard to know, what range to expect.

?I guess you have not sweeped the mixer tank coil ?L6? when set ?Hi , Low at 600 and 1400??? ? to see if it is much the same ??

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At some point maybe you can lift the trimmer cap C4 ?? ?up just to verify that it really reaches minimum… or doesn’t [ simpler than the coil?}

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Now, because of the complexity of the L3 ?coils and the band switch, it is too tough to analyze, ??

Here is a bit more on how I see the first tank, but it needs some reviews, and some clarification but it is a start ???

It would seem that the coil windings and the trimmer should interact with those of the other band ,,, strange stuff I’m shot, good luck

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6SC7 tubes are renown for developing heater-cathode leakage and for developing inter-element shorts and leakage as well.

Often, if you shake one near your ear, you can hear loose whatever rattling around inside the tube.

In addition, thumping a 6SC7 while it’s operating in a circuit can often vary the hum and noise produced by the stage.

I spent over 60 years in broadcast engineering and facility maintenance.? 6SC7 tubes in phono preamps (remember LP’s?) was a continuing headache.

May or may not be relevant in this case.

Mike/
K5MGR
____________________________________________

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Hi Jacques,

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Took the grids to ground, no hum so it looks like it is coming from the 6SC7 area.

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Narrowing it down……….

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I appreciate all of the discussion going on – thank you everyone. We’ll get to the bottom of this one way or another.

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Tom

W3TA

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Jacques, ??yes or a mysterious additional capacitance.? But it is fishy that both L3 and L6 exhibit the same thing and on both bands.

Out the door Friday 5pm ?before Christmas??

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Jacques, we have been to predecessors S-40B and S40A which have similarities, but not even the 40A has cores for Band ?1,2 RF tuning while the mixer tuning.. well things got us really off the rails.

Maynard has been with us too Nick for a bit.

?Ya there is not much there. ?Seems strange.

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Jacques Are you sure you are looking at an S-85?? I see no indication of cores in the RF tuning ?for bands 1,2 ?.

Note Bands go 1,2,3,4? up in frequency, but coil numbers go the other way.. gets us all!?

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Re ???Is it just me, or the two lower band inductors are connected in reverse (one for each other) in the S85 schematic ???

Do you mean L3? which serves both bands ? ?IF so we have gone on wild trips about that. I finally drew the switch wafer in all positions, It is somewhere.

It is too hard to spell it out, without a picture

/g/HallicraftersRadios/message/31639?? ?I drew this just to find out the ground switch stuff while the you need to keep the coils in hand 2.

I could not rotate this switch in my head.

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IF the variable capacitor is the original one, I cannot see else than the antenna coils that have too much inductance.

That will screw both low and hi end alignment.

And it is exactly what happen.

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Emanuele, where are you in Italy ??

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Emanuele, a good question, but that would hardly be in play when at the top end and aligning. But if there is anything but clean air between meshing plates, likely the capacitance would be greater than normal as the plates close.

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Perfect (almost) so this is not the problem.

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73, Jacques, VE2JFE in Montreal

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Emanuele, a good question, but that would hardly be in play when at the top end and aligning. But if there is anything but clean air between meshing plates, likely the capacitance would be greater than normal as the plates close.

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Emanuele,

Second tough?: are you sure that there is nothing in the coils former for both L3 and L4 ??

I never see a receiver in which you cannot “trim” the value of the antenna coil inductance.

Not true, but this was in the WS #19s where the inductances were adjusted by coil winding deformation, but I doubt that Hallicrafters used that…

Otherwise how can you insure a proper tracking ?

Don, Richard: does it rings a bell ??

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73, Jacques, VE2JFE in Montreal

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And the Band Spread variable cap C5A is in minimum position (plates fully unmeshed) all this time ?

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73, Jacques, VE2JFE in Montreal

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Jacques that’s not fair, you are doing your own arithmetic.? And much of what you say must be right, but nobody mentioned what C42 is doing.

In my quick re evaluation after peaking at the manual, without the choke and its cap the output is not what I would call normal/ flat, instead C-42 is pulling down the response[plate AC volts] as frequency goes up. I suppose that can be base boost, but usually base boost does not mean ??kill the mids and really kin the highs.

I will leave it to you to propose exactly how the response works when the out works, I’m gonna cheat and look in the book.

I had to draw stuff, maybe this will help some others doodle around.. ?

Image

End image

Does the rotor plates are positioned in the exact center of the stator ones, or not ??

Please take a picture !

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73, Jacques, VE2JFE in Montreal

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Emanuele,

Fantastic pictures, but I do not believe that the C7A tuning cap can be at fault.

Obviously the coil have too much inductance, so it’s core have to be moved OUT of the coil (to the top, or to the bottom, I do not know which one will be best).

Normally, the trimmer cap should be set at it’s center setting, then the core of the coil have to be adjusted to obtain a peak at the low frequency specified in the alignment instructions, then the response should be peaked with the trimmer at the high frequency specified in the alignment instructions.

Then go back to the low frequency with the core, then to the high frequency with the trimmer, and doing this several times until no improvement is measured.

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But Ah… I understand: no alignment instructions in the manual for the CORES of the coils, like if nobody had touched those since the day of the manufacture !!!

AARGH !

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Find a plastic driver and MOVE those cores while observing what happen with your Spectrum Analyser, PLEASE !

BC band: low side at 600kHz (L3 core ??), High side at 1400 kHz (C4 trimmer), then loop again.

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Is it just me, or the two lower band inductors are connected in reverse (one for each other) in the S85 schematic ???

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73, Jacques, VE2JFE in Montreal

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1. the peak, while correctly starting from the bottom of the band, never ever reaches the top, even when the mail dial is at 1.6MHz; it doesn't even reach the alignment frequency of 1400KHz. This is the problem.
2. C4 (that I confirm is part no. 44-191) moves the peak left and right of about 180KHz; it would be good if the peak would be within a 180KHz span from 1400MHz but it is not.
3. Given this data C4 will never ever "peak" at 1400KHz as required by the alignment procedure.