Hallicrafters

Found a PDF file that not only shows Pictures, but lists all the Model [You must be registered and logged in to see this link.]

Yes. It is fair to say that the NC-46 is more closely related to the NC-80X and NC-81X models than other National sets of the period. I have not owned the post-war NC-46 but I would be willing to say it is quite close to the NC-44 and NC-45 which I have owned and worked on. The slide-rule tuning dial arrangement is much more straight forward and easier to deal with on the NC-44 and NC-45. I would guess so on the NC-46 as well. I would be willing to bet that there is a Sams Photofact on the NC-46 with dial cord restringing info. Having examined the photo you submitted of the NC-46 showing the dial cord arrangement I am going to take another look at what I have here. I am referring to the substitute dial pointer I bought for it plus the spare NC-81X slide-rule dial I modified to take the new pointer. I drilled out some of the rivets on the spare dial to remove the band change pointer section as it looked like part of it would be in the way of the new pointer. This new pointer is a standard one more like the pointers used on the NC-44, 45 and 46 models. Incidentally, I have not been using the band-change pointer mechanism ever since I accidentally burned thru its own dial cord assembly with one of my soldering irons shortly after I got the set years ago. I was sorry at the time that happened. Since then I have mostly run the set on the 80 meter band. With the tuning arranged for 160-80-40-20-10 meters it isn't hard to tell what band you are on or switching to. I might point out that it is easy to forget details like dial cord routing after some time has past. That is why we used to draw diagrams of a set to go by when memory fails hi, hi.

The National 46 sure looks a lot like the 81.
I found a picture of the string from the top of the cabinet. May be of some interest. There was a mention of National having crappy dial string on several models.

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I found some stainless multi-thread stainless wire used for Jewelry making at Walmart. May fit the bill as dial cord for longevity.

I recently started having trouble with the bandspread dial cord slipping and figured I would have to restring it-a job I haven't tackled in many years. Also the dial drums looked pretty rusty so they would need some attention too. I couldn't tell if the Bandspread cord was original or not. It was rather thick looking but well done otherwise. The Main Tuning dial cord had been repaired at some time but not properly. The main tuning did have some backlash as a result of the repair and needed to go. This cord was much thinner than that on the bandspread dial and did appear later to be original.  I resigned myself to getting the front panel off as well as the round dials and get going on it.

The newest dial cord I had on hand was 25' of Antique Electronic Supply's "standard thin @ .028 inches". This had gone bad however and I let AES know and after checking the customer rep Wesley told me that the remainder of their supply had gone bad also in the same way. He didn't recommend reordering it any time soon. I just checked their website and they are offering it but at an increased price of $1 per foot-rather high I think-it was priced at 0.90 a foot only a few days ago. Maybe they tried to salvage the remainder of it.

Well, the SX-99 manual gave fairly detailed info on restringing the dials but did not state the required lengths so I had to guess on that a bit. I checked the lengths of the old cords to have a length to start from. I had to go to a much older roll of thinner dial cord I had here on hand for the job. It is somewhat comparable to what was on the main tuning dial. Removing the rust on the dial drums went fairly well with a small screwdriver. Overall, the corrosion on various parts of this SX-99 has been pretty bad. 

There was one hiccup in the restringing in that the dial drum on the main tuning capacitor had been put on 180 degrees out from where it should have been. That was a bit confusing and hindered things somewhat. The main tuning capacitor kept moving and shifting while I was working since I had the capacitor wide open to get it to match the diagram in the manual. The manual had specified the tuning capacitors to be at maximum capacitance for the restringing. I kept going and did the main tuning first. It came out a little loose but I managed to increase the tension on the dial cord some at the spring. I used a drop of crazy glue on the knots after I was done. 

Next, I did the bandspread dial and did my best on it-I had a guess a bit on how to do it. Then I got it all back together after some further dusting and cleaning. The dials are now working. I have mostly been using the bandspread dial since the restringing. It does have a different feel to it now. I am not sure if I got it all right but not bad for a first try in many years. If the NOS cord I used goes bad then I'll just have to do it again but for now it is ok. 

I'd like to try this on the National NC-81X but the manual is no help on dial cords and I still haven't figured out a way to tackle it. It certainly wasn't made for easy servicing. I recently bought a different pointer assembly of about the right length that I thought might work but was foiled by the location of the dial cord rollers at the upper end corners of the slide rule dial. They sit up too high for the new pointer to work.

73, Rod  WB6FBF

The shafts usually come out OK, provided there is room and the connecting wires are long enuf. Having to re-attach wires can turn into a nightmare. Plus you can break contact lugs off pretty easy on some of the switches.

 I can't remember if a [You must be registered and logged in to see this link.] would work or not. IIRC a [You must be registered and logged in to see this link.] is too big.
 I got an eyeglass repair kit off Amazon that has some really tiny bolts and nuts. I would not use a self tapping screw, as the bakelite is brittle.

If you need fingers, let me know & I'll try to find you a wafer.

Yes. It is phenolic. Right now I just need one finger contact but some spares might come in handy if I have trouble. Would it require a number 2 screw or would a number 4 fit? I have some number 4 screws here-probably 4-40. I also have some very small sheet metal screws that National used on their receivers for various purposes.  I have a few of those here. Right now, I guess I could use just about any wafer for the parts if not an actual SX-99 mixer section wafer. I also studied the bandswitch shaft setup and think it will come out if need be.

I have actually replaced the fingers on those switches. Not an easy job.
 You will need to find a very small screw & nut to fit the hole.

I might have a suitable wafer, if I knew what yours looked like, number of contacts, etc. I would guess yours is phenolic and not ceramic?

I did some more checking this morning and found that another finger contact (for band 3) was not making contact with its rotary pole in the 6SA7 mixer section. It was not up in the air as much as the one in the antenna section but still it was not making contact. This was a much easier fix as all I had to do was push down on it a bit with my small screwdriver. I did over shoot it but it was easy to raise it back up and now it makes good contact. So band (3) is working now and it was good to be able to tune in WWV @ 5 MHz this morning.

I have heard of some restorers replacing wafer switch fingers and so forth by drilling out the damaged section's rivets. I would think that would be a delicate operation even after you manage to get the wafer section free of the receiver. Drilling out a rivet on a bakelite wafer would seem to be a bit risky. There would be a number of wires to disconnect to remove a section from the SX-99 after the switch shaft was removed. The antenna and rf sections are modular and look considerably easier to remove than the oscillator section. I did replace a ceramic switch section in a Signal Corps BC-312/342 receiver one time and that was fairly easy to do due to the set having been designed for easy servicing. I might have replaced the whole module in that BC-312 receiver which would have saved time-not sure now. I just happened to think that I have some very small sheet metal screws and perhaps it might be possible to screw down a new finger on top of the old one without removing it. I'll have to look in to that. 

Well, we can't go to a Hallicrafters service center now for spare parts. So I'll keep your suggesting in mind for buying a spare wafer switch for the parts. On the other hand, looking out for a junker SX-99 could be a source for a another wafer. It will probably be in better shape though than the receiver I have now hi, hi. I was about to try to get another SX-99 before I started on the bandswitch scrapping and made some progress on it.

73, Rod Clay  WB6FBF

If worse comes to worse on the switches, Here is a page of wafer assemblies that may or may not be of use from a good source of older NOS components.

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I thought I would do a follow up on the SX-99 bandswitch problem. I received the EF eraser pencils this morning. They are NOS so I can't say how old they are. They are marked "Made in USA".  That should put them back a ways. Well, I tried getting one of them sharped using my church's office sharper with mixed results. I could not get a point on it. The rubber is rather soft and on the crumbly side which I found out after I got started on the receiver. I don't know if this is due to aging of the product or not. I didn't want to spend $30 plus shipping for a new German made (12) pack (from a Walmart seller). As it is I paid $21 post paid for a vintage box of (6) so maybe the box of (12) was a better deal.  

Anyway, after I got started on the bandswitch I found that the eraser pencil was not going to do the job alone so I got out one of my small screwdrivers I keep here for scraping purposes and literally started scrapping away at the bandswitch rotary pole sections. These were much easier to get at on the (3) wafer sides facing towards the rear of the set. These were badly corroded and also appeared to have some other crud on them that may have been deposited there over the years the set had been in storage. The eraser pencil came in handy to polish up the section of switch I was working on after the scrapping was mostly done. I didn't try to do anything with the switch fingers. I noticed after getting the pole areas clean that corrosion came off the fingers with changing of the bandswitch postion several times back and forth. 

One thing I found that made the receiver dead from the antenna connection back was that one of the important finger contacts that goes to the 6SG7 RF stage grid was not contacting its rotary pole section at all-it was just sitting up horizontally in the air. I worked on that finger contact for some time trying to get it down to where it would make contact and stay there. 

While that turned out be eventually successful, I ended up damaging and breaking off the finger contact for the number (4) band position: part of the 6SA7 mixer section. I was polishing a section with the eraser and pushed too far without watching what I was doing. So that band will not work again unless I can get another mixer wafer for it. A shame since it covers 20 meters, 15 meters and 10-11 meters. These finger contacts are made in pairs but since I can't get to the under side of the rotary switch sections to clean them I don't expect the band to start working again. It is not working now. 

I was able to restore reliable operation on bands (1) and (2). So I can copy 160 and 80 meters now as well as the Broadcast Band.  I can get WWV at 2.5 MHz on band (2) but not 5 MHz as band (2) does not go up to 5 MHz. I am not getting anything on band (3) which means no 40 meters. I am not sure why this is. Tomorrow I'll take another look at it. Maybe I missed something or damaged some other contact. It is rather fine and delicate work. 

So for now I have (2) out of (4) bands working. 

73, Rod Clay  WB6FBF

Yes. There were a lot of Globars made for use mainly in TV sets. Most of them aren't suitable for use in (4) or (5) tube table radios. The globar used in the Hallicrafters S-120 was rated at 800 Ohms cold and 100 Ohms hot. 100 Ohms is the right series resistance to add to the set's series string of filaments (tubes and lamps) to bring the line voltage up to 115V. I had to use a 130 Ohm wire wound resistor as it was the closest I had on hand and it is a 5W job. Good enough and it brings the total voltage drop to 120V-better for today's line voltages. Still, the inrush current is a bit high and has been causing some problems with the two series connected [You must be registered and logged in to see this link.] dial lamps. So now I have parked my variac next to the radio and use that to ramp the line voltage up and down. One change is a much more rapid warm-up of the set as it took about a full minute with the globar in there. 

The National NC-81X has a similar filament arrangement although it is a (10) tube set using 0.3 Amp tubes on the filaments. It uses a 90 Ohm wire wound dropping resistor in series with the filaments. The (3) seriesed [You must be registered and logged in to see this link.] dial lamps are bridged across part of this 90 Ohm resistor.  They have been surviving turn on surges of the set.

I looked at the schematic and it may require that the glow-bar replacement resistors be wirewound.
My Idea is that the wire-wounds have some inductance which will prevent full current to pass, until a certain time has passed. That's one reason their used in power supply circuits to allow the tubes to warm up some what without a sudden surge of current passing.

The schematic I am reading has a scribbled note on it that is hard to read. They suggest 3watts each (I think) but I would go with 5 or even 10 Watts to be on the safe side.

Excel is a spreadsheet that you can do many things with.
Make your own library, of Tube, resistor, capacitor, Hardware, fasteners, Address list(s) for mailing(s),  inventory.
Taxes, in other words you can make lists for your own needs. You can search and sort to your liking.
There are many free software programs that you can use that are just like Microsoft Office. One is Open Office ( I have used that one and it will recognize Word, Excel, Powerpoint, Access formats)
Here's another one on line, That I haven't used but you may want to look at the free version.
FoxPDF Click Here

Another one for editing PDFs is called PDFill PDF TOOLS Free. (this one I use to take almost all documents and make into PDF files.

For Word documents just type in your search engine the words "Free Word Viewer"
From what I gather Wordpad will open *.DOCX files it comes in most versions of Microsoft Windows

I did a similar recap for a Hallicrafters S-120 and I wish I had gotten the Hayseed Hamfest kit or at least the clamp mounted electrolytic they offer for that job. Installing individual electrolytics in a crowded chassis not designed for it was not an easy or fun job. I ended up damaging the series string Globar resistor and had to replace it with a standard wire wound resistor and now have problems with dial lamp blowouts.

Do you know EXCEL or Microsoft Office? I have never really used either. I did once have a WORD viewer installed to read their documents but seldom used it. I tried to get the free Microsoft EXCEL Viewer this week but it is no longer supported or available. I had never heard of .XLS file extensions (for Excel) until this week when I got one in an email with that type attachment containing a quote from Digi-Key about a Hammond driver transformer that I am trying to order. I had to get them to resend it as a PDF after (2) free viewers I downloaded and installed couldn't open it. I guess they figure everybody has Microsoft Office installed and uses spreadsheets (what are they anyway?).

I found out there is a lot of paperwork involved to order a part that is not normally stocked either by a distributor or manufacturer even though the part is listed as a good item on the manufacturer's website-Hammond in this case. I am trying to get a Peter W. Dahl replacement driver transformer (made now by Hammond) for an EF Johnson Viking II amateur transmitter. Hammond has taken over the old P. W. Dahl lines of Amateur and Commercial transformers. Well, in my case I had to print out and sign an agreement that I would not try to  cancel the order or attempt to return the item (unless defective). It's not like we are talking about thousands of dollars here for the order. I had some difficulty getting the document sent to Digi-Key (by email as an attachment-I wanted to save time). I still don't know if they got it or not. Just to be on the safe side I mailed a copy to Digi-Key. Maybe they will get that by next Wednesday. Then they will give the signal to Hammond to start working on the order. Hammond told me previously that it could take 6-8 weeks before it would be ready. That puts it in the spring time for delivery. I hope it will fit and sound good on the air. Time will tell. 

73, Rod  WB6FBF

My good neighbor just gave me a Hallicrafters model S-38E.
So I will have to replace all the caps before turn-on.
Looks like I am going to order the Electrolytic's.
There is a kit online, but its well over $30. So I guess I will bit and piece them together.
I couldn't even tell where the caps were that I do Have  
I do have a spreadsheet but have many duplicates as far as workbooks and worksheets to compare.
Just learning the tricks for Excel. So a long sordid search, consolidate and DESTROY, MUH_HA_HA :twisted:

You might look on Ebay for a mechanical sharpener.  The ones that have a single blade over a conical hole don't do very well with these.  The ones with the rotating cutter that looks a bit like a reel lawn mower, (like the old school sharpener) cuts them well and gives a fine tip.  I see new ones on Ebay for around 8-10 bucks.

I bought a box of (6) of the Eberhard Faber [You must be registered and logged in to see this link.] eraser pencils this morning so if anyone else wants to give one a try just let me know. It looks like EF is currently marketing a box of (12) similar looking eraser pencils under a different part number (made in Germany) available online at Walmart from an independent seller. Now I may have to buy a pencil sharpener to go with the eraser pencils.

The old fashioned wood cased typewriter eraser always worked best for me, especially getting into the tuner strip contacts.

Here is what I use to clean wafer type switches.  They sharpen with a pencil sharpener and you can place the tip on the contact plates and work the switch under it.  It is rubber with a mild abrasive .

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I just got in here an SX-99 that looks fairly good on the outside and the chassis is mostly decent looking too but it was obviously stored for some time in an unheated, damp location. Creeping corrosion are the words that come to mind. I was hoping for the best after seeing this and went ahead after checking it over, replacing the 1950s tv set black color coded tubulars first then the Tiny Chief tubulars. I was thinking of buying one of those cap assortments for it with a new can electrolytic but now I am glad I didn't spend the money and used what caps I had on hand. All of the resistors more or less checkout. Most of them have increased in value but not terribly so. I don't think the set has seen any servicing-just a couple of modifications to the back panel one of which is good-a jack for receiver muting via a changeover relay.

I haven't looked at any of the micas in the set and there are a lot of them. Only one ceramic disk cap is used in the whole set. It is a screen bypass for the 1st IF 6SG7 stage. The voltages are right according to the Hallicrafters SX-99 manual available online.

The bandswitch contacts look to be in bad shape due to corrosion. Worst I've seen. I've got the set somewhat playing now after determining that the hfo was functioning as I was able to pick up its signal on the National NC-81X. I cleaned the bandswitch in my usual way with the limited supplies here. I use silicone spay lubricant with  a vigorous back and forth action for switch and control cleaning. It does a fairly good job of contact cleaning. For bandswitches I follow that up with a no residue contact spray cleaner to remove the oils.

Well, I got some stations in the BC band by clipping on an antenna right to the 6SA7 mixer stage tuning capacitor. Putting the antenna on the antenna input terminal on the back of the chassis just leads to silence. It appears no signal is getting thru the antenna input and into the 6SG7 RF stage. Clipping the antenna right on to the RF stage tuning capacitor results in a much weaker output than at the mixer tuning capacitor.

I am wondering if someone can make a suggestion of what I could try on the bandswitch contacts to get them in better shape. I would like to salvage the receiver and put it into use here. Any ideas?

73, Rod  WB6FBF

I have an S-107 that I re-capped a couple of years ago.  I've found that my receiver in my Magnavox console is pretty much parallel to it in performance, and with limited display area, it doesn't get much use.

One of my favorite  Hallicrafters is the SX-96. It has the same basic circuit as the SX-100 but fewer complications inside from lack of the notch filter circuitry and somewhat simplified front panel controls. I enjoyed operating the one I had. Current Hallicrafters here is the little S-120 that use to listen to 75 meter AM phone QSOs and Nets on or about 3870 kHz. 73, Rod

We just got a S-20 working for our exhibit. We had a donation and it required re-stringing of the dial. No easy way to do that but to  take the front cover off. Just make sure to replace both while you are there.We had to replace one tube and he main electrolitic cap. But it is a great receiver for it's age.

As an added note, All of the Hallicrafters sets I have seen have silver mica disease in the IFT's.
Also an OT told me their wire in the IFT's was subject to insulation breakdown. Something to do with age and the wire insulation. He MAY have gotten that confused with silver mica disease though.
 At any rate, replacing the IFT's or the fixed mica's in the bases of them is the only cure.

The S-38 series consisted of the : S38, A,B,C,D,and E, that I have owned or seen.
The E was totally redesigned mechanically, and used miniature tubes, IIRC.


 I do have a Sky Buddy in the garage, missing the case. It belonged to my best friend, Jay Davies.
 Had a bad IFT in it, and the replacement is still dangling out of the chassis by wires. He is an SK.
I just have not had the strength to finish the repair and find the rest of a case for it. We were buddies for almost 30 years.  One day I will finish the repair and give it to his widow.

I have a Hallicrafters S38d (last of the series with octal tubes) and an S120.

I was one of the bidders on this one;
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There was only one bid and I made my bid in the last 5 seconds in order to win but one more bid got in right after me!

I have just one Hallicrafters now SX100 Mark1A
I sold my others SX 62 and S20R

The value isn't too bad, but a Hallicrafters collector or ham, may pay a premium. I guess in the range of $75-$175 depending on condition too.

I've been following this post about the fine SX-100 receiver. I have the same, but in MarkII configuration. Anybody know about the value of the HT-19 NBFM (80-10 meters) FM CW only transmitter? I have had one of these in really pretty good cosmetic shape for years, thinking I would at least get it back on the air on CW. Still might happen. Have a nice SX-43 with FM and it's a joy to listen to as well!

I remember reading that a lot of problems with wire coatings out-gassing sulfur and that is corrosive to copper.