Richard, yes it is hard to describe what is actually a drawing on paper.? Perhaps you don’t have anything to copy what you see.

Here, I am using ?

and see ???this

As I see it , C10 is only used in band 4 ?

?

This is getting difficult to talk about. Yes ?The antenna stage, i.e. the
circuit between the antenna and the RF grid, is virtually the same in
both receivers. Yes [S-85 ?and S-40B {reference} ] ??The plate circuit is not the same. Yes?? ?

?

In the S-85 the
broadcast band (540 to 1600) is not the same. Yes ?In the S-85 the plate load
of the RF amplifier is an untuned 6800 ohm resistor R-29 and C-26, a
220uuf capacitor across it. Yes? ???This is capacitance coupled by C-10, to a
tuned circuit in the grid of the mixer tube. No ?look at image.

?

The antenna tank and this
tuned tank will have some selectivity but it will be lower than on the
other bands. ??

?

On the second band there is a 6800 ohm resistor acting as
the plate load, Yes ?also coupled to the grid of the mixer through C-10 No with
a tuned circuit in the grid. ???No, I see a 6800 ohm resistor ?running to band 3 coil L5 ?but there is no ?OBVIOUS path to the grid cct WHEN ON BAND 2; ?admittedly a very strange dangling signal raising all kinds of questions????????? Without the 220uuf cap the gain should be higher. ??, ????????Both coils for the mixer grid [L6] seem to be wound on the same ?former with separate trimmers. Yes? ???

The puzzler here [we are trying to solve the band 2 mixer dilemma ]? is ??????where is the ground return for the antenna stage
of the two lower bands? ??? ???On the two top bands the coils are link coupled
with one side going to A2 and grounded through the link on the antenna
termimals. On the two lower bands there does not seem to be any sort of
ground return for an ballanced load. A2 does not go anywhere. True on
both the S-40B and S-85. If a single wire antenna is used the return is
via the ground terminal, A2 goes no where. Yet the receivers is
specified as using either a single wire or balanced antenna on all
bands. So how are the two grid coils on L3 connected for a balanced
antenna? We have discussed all sorts of illusory connections but I
still can't see how any of them work or how to prove that they work.
My suggestion of connecting a signal generator or other source (a
piece of wire) to A2 with A1 grounded is to see if there is any signal
that way.

I [we] have seen no answer and ?gave up long ago and resorted to a long wire and the link closed to solve Emanuele’s problem ??

Now, the original question was why do not the trimmers on the two
lowest bands do anything? Not accurate, read again from the start.. all words matter. First of all, is this correct, do neither
antenna or mixer trimmers work? Is it on both bands or only the antenna
stage? I will find the original post and see what was asked. You need to read all his posts again, if you want to understand the situation.
This may be a separate problem. Now, I don't want to go through the
entire long thread again (but will despite being lazy) but have we heard
from anyone with a working S-40B or S-85 about whether their trimmers
work or whether their receivers have reasonable response on the two low
bands? read all ?posts again ?Hallicrafters made both receives for some time so they can't
have been totally inoperative on even one band let alone two.
The original poster (not sure of spelling Emmanuel?) seems to have
an adequate signal generator. Could he try feeding a signal into the
grid of the mixer tube or at the plate of the RF amplifier (using a
blocking capacitor) to see if there is response at that point. read all his posts again as he has done equivalent tests I think
If neither trimmer works its necessary to isolate where the problem
is (could be both places). read all his posts again
I have no definite suspicions at this point. The circuit is a
puzzle because as its shown it appears that it can't work. We have been
over the possibility that the schematic is wrong or that the receiver is
wired wrong (would never have worked so how did is escape from the
factory?) ?it is always possible on friday 5 PM before Christmas and the boss says “meet the quota for the year”???????

?I still want to know what happens if a signal is injected into the A2 terminal with the A1 terminal shorted to ground. ?Wait your turn Richard, don’t get pushy, he has to go to work {big smiley thing|.

You can ask all the questions you want, but like the lawyers, you need to know the answers yourself. or

?Questions ?are cheap, ?the answers is ?“don’t ask me”

?