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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Tue 13, 2020 7:08 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
I vacuumed a fair amount of debris out of there before taking the photos. The top of the set really is pretty nice. Both dial strings are still in place, threaded through the
correct way. I usually hate dismantling a set for parts.


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Wed 14, 2020 4:08 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Latest: in spite of the rust-bucket appearance, all the knobs (and the bandspread dial) came of in five minutes. None of them were rust at all, amazing. The bandspread dial is in excellent shape, so this may be the first donor item to the original set. Have not cleaned up the front panel yet.

The really interesting part is the small user-mod aluminum can, with toggle switch on top. It contains a single 9005 triode, and seems to have its circuit put in between the last IF stage and the detector/first audio stage. May be tough to trace out given the state of the wiring on the underside. Photo to follow.


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Thu 15, 2020 8:08 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Photos of the funny can modification, and the connections inside the set.

Also, the front panel is nearly pristine! That may be the next donor item from this set.

This set also has what seems to be a factory IF bandwidth adjustment - toggle switch on the rear panel
that seems to be involved with at least one IF can. This is not seen on the schematic but is definitely a
factory option as the switch has an original metal tag for it, on the cover.


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s11_mod_internal.JPG
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s11_panel.jpg
s11_panel.jpg [ 305.14 KiB | Viewed 666 times ]
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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Mon 19, 2020 5:39 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Latest: all the audio transformers, and the filter choke, check out good. I've taken the phone jack from the donor set, cleaned it up, and have it ready to install.
The main tuning gear reduction mechanism is cleaned and lubed, and the main tuning shaft with the flywheel, has been taken apart and cleaned and lubed.
Both the main tuning dial and the band indicator (operated off the bandswitch) have been re-strung. The bandswitch was blown out and gently lubed with tuner cleaner,
*only* on the contacts. Learned that one the hard way a while ago.

Also replaced the antenna feedthroughs, with non-stock parts. But they look cool. Had to make the thinner thumbnuts though.

The punch list on this set keeps having things checked off, but for some reason, the list keeps on growing.


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phone_jack.JPG
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re_strung.JPG
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antenna_posts.JPG
antenna_posts.JPG [ 319.01 KiB | Viewed 640 times ]
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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Mon 19, 2020 7:32 pm 
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Joined: Jul Fri 10, 2020 11:10 pm
Posts: 268
Thank you for your work on this project, Jim. I look forward to following the progress and seeing how you attack the problems.

Best,

_________________
Greg


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Wed 21, 2020 7:20 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Well the crystal seems to be good, it's not apparent from the trace below (I figured a better way to measure it) but the Q is 50,000:


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xtal_data.JPG
xtal_data.JPG [ 329.62 KiB | Viewed 603 times ]
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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Wed 21, 2020 7:32 pm 
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Joined: Jan Tue 10, 2012 8:39 am
Posts: 1965
I got a big chuckle at the old and the new. A modern spectrum analyzer and a vintage receiver. And it points out the good engineering with no fancy test equipment.


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Fri 23, 2020 4:16 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Yep, old school, working here one of the perks is you can hook one of these up to a relatively high end network analzyer:


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hi_power_xtal.JPG
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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Sun 25, 2020 4:12 am 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Two new developments:

1) this set was improperly wired from the factory. It's missing a wire from one of the audio transfomers, to the tone control.
There's a capacitor in that circuit, that is open-ended, and the location where that wire should terminate, is missing that lead.
The other set (the 'parts' set) has that wire in place. The first set never had the tone control working.

2) the schematic does not accurately reflect the BFO injection, as it's wired in both those sets. The BFO is coupled to the
detector tube diodes via a gimmick capacitor, not a discreet mica at the BFO tube. Instead the BFO signal is brought
to an unused pin on the detector tube, crossing over the diode leads. It's implemented in exactly the same way in both
sets.

Once I sort out the audio gain control and the wiring for the phone jack, it's time to remount the front panel.


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Mon 26, 2020 4:37 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Actually it was missing two wires - the one for the tone control (and this really was a factory error, the capacitor feeding that control is soldered neatly on the terminal board, but one end was empty except for the capacitor lead - and it was a factory fresh joint. The other one missing was the wire from a 6L6 grid that actually feeds the headphones - that wire was probably removed when a previous owner stole the headphone jack - I can see when 6L6 the wire used to go to. Newly wired phone jack section:


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phone_jack_setup.JPG
phone_jack_setup.JPG [ 257.92 KiB | Viewed 510 times ]
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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Wed 28, 2020 3:10 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Really coming together with the mechanicals. Front panel is on, knobs and main dial, dial pointer, phone jack, all controls in place. I've re-stuffed the electrolytic filter capacitor and have a bottom panel made up. Need to mount up a few more front panel details like the index for the bandspread dial and the dial lamps. I need to source what are apparently no. 46 pilot lights.


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front_panel_on.JPG
front_panel_on.JPG [ 232.36 KiB | Viewed 478 times ]
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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Wed 28, 2020 8:28 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1571
Location: Morris Plains, N.J. 07950
Jim, it looks like Sal has them.

http://www.tuberadios.com/capacitors/

So does AES.

https://www.tubesandmore.com/products/dial-lamp-46-t-3-14-63v-25a-screw-base


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Thu 29, 2020 7:58 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Thanks for the sources. I was actually able to buy these via amazon.

Replaced the eye tube wiring, and put in the re-stuffed electrolytic last night. Next step is a line cord and a fuse.

Then, time to try powering up, smoke - here we come.


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Oct Fri 30, 2020 3:43 am 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Ah, not bad for the initial power-up.

The BFO is a bit weak, and the lowest band is completely mute. The tuning eye tube a wee bit dim, and I'm pretty sure I have the AVC on/off toggle switch upside down. But the next two upper bands pretty active, all other tuning controls operate correctly. The crystal operates more or less correctly.

Not sure what the B+ should be, but it's 250 with 110 volt input.

The 6L6 pair get *very* hot, might need to look at the bias situation there.

Quit pleased - this has not been aligned since it was maufactured I think


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Nov Sun 01, 2020 7:27 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Bottom is on the set now, and a quick rough alignment revealed that it was pretty well aligned as-was!

The lowest band is now working fine so there may have been some intermittant there, still to be chased down.

1) the highest band is completely dead - won't even see a strong rf generator signal.

2) the BFO works, but barely. Tried swapping tubes, to no avail. Will poke around to see if any components are out of spec. There's no information in the manual about setting it up or adjusting the trimmer on the coil. Another point to ponder - the circuit as built, does not agree with the published schematic - the diagram shows the BFO coupled to the plates on the detector tube, via 250 pf capacitor - but both sets I have cross the feed from the BFO close over the leads to the plates, but terminating on an unused pin (6).

3) the AVC switch is still upside down...

4) I have not yet found a list of votages for this set - the B+ is 250 but I'd like to see if that's close. Also the cahode voltages on the 6L6 output stage would be nice to know.

5) The tuning eye tube works - *if* all the lights are out! The one from the parts set about the same. How to pump that up a bit?

6) The biggest problem in allgnment was the main tuning dial was installed quite a bit off originally. When I had to drill out the dial setscrews, this left divots, in those wrong locations. The trimmers and padders did not enough range to bring it back in. Solution was to machine up tiny slugs to fill the divots, epoxy them in place, and then carefully file the shaft round again.

The set is very stable, and the selectivity with the crystal in is very sharp. Single signal reception of CW on 40 M today. When the AVC is on, and there's no signals, the noise level goes way up - Possibly the rf stage needs a different tube.

My punch list is long, and getting longer - things are going on it at the same rate the're going off.


Last edited by jim rozen on Nov Mon 02, 2020 5:06 pm, edited 1 time in total.

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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Nov Sun 01, 2020 7:41 pm 
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Joined: Jan Tue 10, 2012 8:39 am
Posts: 1965
A dead high band indicates that the local oscillator isn't running. The tube may be weak or a bad connection to the bandswitch or just too low a Q for the gain available.

Much of the rest of your message isn't comprehensible to me. Perhaps you should reread your messages before you send them. Complete sentences, correct spelling and grammar, etc. are important when discussing technical topics. I am not being disrespectful here, just confused, especially the part about the tuning eye.


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Nov Sun 01, 2020 9:52 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Eye tube works IF the room lights are out. Keyboard on this laptop a bit wonky.

It's a dim 6G5 apparently.

Bandswitch and coils apparently good on that band, the plate resistor has drifted a bit high...


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Nov Sun 01, 2020 10:16 pm 
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Joined: Jan Tue 10, 2012 8:39 am
Posts: 1965
If B+ is reaching the eye tube and it's dim, it's just worn out. Eye tubes are generally short lived.


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Nov Mon 02, 2020 5:05 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
I was afraid of that. I seem to have two worn out eye tubes....

"A dead high band indicates that the local oscillator isn't running."

And the plate load resistor on that has drifted quite high. Will replace that next.


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 Post subject: Re: Hallicrafters S-11 project
PostPosted: Nov Tue 03, 2020 9:18 pm 
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Joined: Mar Wed 16, 2011 10:44 pm
Posts: 1652
Location: Peekskill, NY
Several values of replacement power resistors are now on order - and I coupled the BFO output to the detector tube the way the schematic shows, and there's a *vast* improvement.

I think these were built on assembly lines, and probably some of the assemblers were better than others. I found one more wire, which was clearly installed, wrapped around the tube base lug, but never soldered!

My hope is getting the correct plate load for the 6C5 oscillator will bring the top band to life. Photos of the set in operation, lit so the wee little eye tube is visible:


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running_1.JPG
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running_2.JPG
running_2.JPG [ 206.08 KiB | Viewed 323 times ]
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