Nuther Load Today!
Another interesting load arrived today, This was a smaller load as the person carrying it for me had less room in their car than some of the others, but that didn't make it any less interesting.
Included was a neat little Stanley & Patterson anunciator, two NE 17C magneto test boxes, another Russian Princesse (Crouse-Hinds explosion proof phones), an ancient arrestor, and a number of interesting NE intercoms the same as one which came in an earlier shipment. Used as packing material were a bunch of NOS 7 foot switchboard cords!
The Russian Princess has the switchhook arranged for wall mounting.
Don tells me he had a lot more for the museum, and I am looking for more people coming to the Island to bring more down.
Here is a photo of today's lot!
For comparison, here is a picture of a restored version of David's magneto switchboard. I took this picture at the 2013 Lancaster show. David's board matches it perfectly, only his is more barn-fresh, unlike this restored version.
It is a Northern Electric cordless magneto switchboard with five talk circuits, ten magneto station loop circuits, and controls for one operator console. The station circuits could be used as manual tie trunks just the same.
The orange switches connect a station to one of the first four talk circuits, up A and C, down B and D. The black switches of the bottom row have dual function, in the up position they connect a line to the fifth talk circuit (E), while in the down-position they ring a line when the generator is cranked at the same time by the attendant.
The five drops at the top are to indicate ring-off has occurred on an established talk circuit, to alert the attendant to tear down the circuit. On later automatic cordless switchboards with lamps, this would be detected automatically when a station went on-hook; a relay would activate a lamp and sound a buzzer. With these manual boards, a station user had to crank the generator briefly after hanging up.
The second row of drops are alerts that a station user wants service. They crank their generator, and the attendant sees who is requesting it. She would connect her attendant console to the line with the orange key (up) on the bottom row to the requesting circuit (black up). On Dave's board the orange key is also black like all the keys of the bottom row.
The white keys are listening keys so the operator can connect to any talk circuit and intervene or simply listen to find out if the circuit was still in use, in case someone didn't ring-off their call.
Of course, the G-type hangup dial hand telephone, attached to this board at Lancaster, is an anachronistic modernization. However, from what I understand magneto boards were used in Canada much later on the average that in the US, but a dial on this board does seems a bit novel as it requires battery.
Catalog #5 (1923?) shows "No. 505 Cordless Type" switchboards "designed for both central battery and magneto service."
"505B"-- 3 trunks x 7 station lines-- Trunks connect to Central Battery manual office
"505C"-- 3 x 7 Private Branch Exchange Switchboard--Trunks connect to C.B. machine switching office
"10 Line Cordless Magneto Switchboard"--"equipped with 10 magneto station lines, any of which may be connected with a line from a magneto office for trunking purposes."
Quote from: unbeldi on July 16, 2014, 10:00:07 AM
For comparison, here is a picture of a restored version of David's magneto switchboard. I took this picture at the 2013 Lancaster show. David's board matches it perfectly, only his is more barn-fresh, unlike this restored version.
Thanks, Karl! It will live again!
There is some kind of designation stamped into the edge of the wood panel in the inside view. It may indicate the model number, or not. Starts with 5 in any case.
The same picture also shows the connections for the ten stations, T and R, as well as a few additional one, marked with plus and minus signs. G and G1 are no doubt the generator connections, implying perhaps that an external generator feed could be used. I can't make out the designation for the two other terminal pairs. They have + and - characters, but this could be an indication that the same connecting block was also used for the common battery versions of the model. In any case, it seems one of them should be the operator console, unless there is an induction coil mounted somewhere else in the unit to which the console attaches directly.
That brings up another observation, there does appear to be a 101-type induction coil further down inside the unit at the end of that thick harness. Likely that is a later addition for the operator console. Perhaps David can shine some light on that, and see if it is a 101 or a 104, who made it (WE or NE), and what its date is.
"The operator's telephone set includes a desk set with black finish complete with receiver, transmitter and cord and is operated by the key on the extreme right."
The photo shows a 20-type desk stand only; so, the induction coil would be inside the P.B.X. and the external talk battery for the operator's phone would be connected to terminals in the P.B.X.
Quote from: unbeldi on July 16, 2014, 11:57:28 AM
There is some kind of designation stamped into the edge of the wood panel in the inside view. It may indicate the model number, or not. Starts with 5 in any case.
That brings up another observation, there does appear to be a 101-type induction coil further down inside the unit at the end of that thick harness. Likely that is a later addition for the operator console. Perhaps David can shine some light on that, and see if it is a 101 or a 104, who made it (WE or NE), and what its date is.
Ah, now that is how bad my eyes are now - I never noticed the designation when I was looking right at it. Just got another shot in my left eye this morning....
I will have to have a really good look at it with a magnifying glass and try to make it out... Funny thing is I had looked for markers that would help to identify it and completely missed that...
Now, about the induction coil.... Unless I can make it out from the top, that will have to wait until I can re-glue the laminates between boards in the cabinet. The reason is, if I unscrew practically anything at this stage, the boards will fall onto the table around it like a stack of cordwood. Every bit of glue on it has failed. Thankfully, other than needing refinishing, the wood itself is in good shape - it is only that the glue has failed.
So, being overly cautious, perhaps anal by nature about things like that I'd rather take my time and re-glue it side by side before I take it apart to the extent needed to see the coil better. However, I promise to take a look at it tonight to see if I can make out anything without going to the extent of beginning to disassemble it.
The problem is, as you can imagine, is with this amount of stuff arriving within the past couple of weeks, and just as much more expected, I have to spend my time now going through and cataloging it all, safely storing it, and/or putting it on display, and tons of cleaning and minor repairs! It is a bit of a nightmare, but one I am thrilled to have. I have never had a find like this before, and I one never expect to have again. The photos I have posted here are only the tip of the iceburg.
So with much, tonight I may be able to find the info you are looking for. I do have a magnifying glass over in the office, so I hope it will allow me to read the numbers. Unfortunately, I can see almost nothing out of my left eye right now after the injection in it.
I also aside from sorting and cleaning items, hope to find time to call a local carpenter to see if he has a suitable piece of oak of maple in his scrap pile to make a new lid out of. He does some furniture making, so there is a possibility. I am not really certain what wood it is made of. but I am hoping I will be able to get an old piece of solid full dimension lumber from him I can use to make the new top.
I don't think I have had so much fun with any one particular piece of equipment since I got my 1240 switchboard and got it going! Thanks, Karl and all!
Update: I just had a look at the unreduced photo of the board I took yesterday, and on another photo I didn't use, it shows what I think is the full number (to be verified latet). It is either 521 or 5.1 as in the photo below... This photo shows a little bit further to the right of the other.
Dave
I have found that I observe much better on pictures, if they are good, than on the items directly often. A picture provides some kind of steady focus and lack of distraction by surroundings, I suppose.
No rush with the identifications... You have a lot to cover already.
Quote from: DavePEI on July 16, 2014, 03:24:42 PM
Update: I just had a look at the unreduced photo of the board I took yesterday, and on another photo I didn't use, it shows what I think is the full number (to be verified latet). It is either 52 or 5.1 as in the photo below... This photo shows a little bit further to the right of the other.
Dave
How did you arrive at 52 as a possibility? Perhaps this image is again too low in resolution....
In fact I know it is, because there is already too much information loss for image enhancements. It's only 72dpi.
Quote from: unbeldi on July 17, 2014, 03:06:03 PM
Quote from: DavePEI on July 16, 2014, 03:24:42 PM
How did you arrive at 52 as a possibility? Perhaps this image is again too low in resolution....
In fact I know it is, because there is already too much information loss for image enhancements. It's only 72dpi.
Don't forget, I have the un reduced photo here at full resolution. But, it won't help you as I said, it is either 5.1 with the ) looking like an o, or 521 with only the lower portion of the 2 showing. If it was a 2, the punch was on an angle so didn't cut the upper portion, but there are vestiges which look as though it could have been a 2. I had another look at it today with a high powered magnifying glass and I stick with that. The only one questionable at all is the "o" or "20".
The one thing I did discover today is that the glue isn't as bad as I had previously thought. There are 3 seams which have come undone, but I should be able to re-glue them tomorrow without a lot of trouble.
I picked up a piece of birch plywood to make a temporary lid for it until I find a piece of hardwood to do it. It was going to cost me $100 to get a piece joined with biscuits large enough from hardwood. So hopefully this will do well enough to serve for the time being. Hopefully I can find a piece off some old furniture in a yard sale this summer to make the final top.
The ply was only $5. Birch plywood takes a wonderful finish - my desk here is made of stained and varnished birch plywood, and back when we were selling some of my parent's antique furniture, a lady asked me how much I wanted for the "lovely antique desk" :)
Another advantage of my using it is I can use it to get the holes in the correct position and then I can use it as a template for the final top. I am thinking of dropping cut nails in the old screw holes to mark the correct position of the screw holes so that the new top will screw into the existing holes.
I did drop the front today, but there wasn't have time to take photos (I had the camera over there, but the memory card was in this house) and I had to leave direct from there for the lumber store. I will vacuum the inside and post a photo of it tomorrow.
Ny the way, the overall dimensions of the top and bottom of the board are 19.5 x 17 inches. I didn't measure the height as I was in a rush to get to the hardware store.
Dave
For anyone who has been following the switchboard, I finally got three of the sections needing re-gluing done this morning, and it is now clamped and drying.
After it dries, I have one more spot to re-glue, one which would have been difficult to clamp at the same time as the others.
I took a couple of photos of the board while I had it open you might find interesting, one showing from the door back, and one showing the door equipment. I also took a photo of the coil, which might be of interest. It is indeed a 104A and carries the date 1943...
Dave
Ok, good to know that the coil was indeed a 104, which is what a local battery system should have. A 101 would have probably shown that some collector bastardized the box. This seems very original and makes sense. I am sure these boards were still in use in the 40s, and even a decade later.
The 104 is also missing the resistor, which is right on, because it was used for the attendant station, and didn't need extra loop compensation, ergo they saved the component altogether. This might just indicate that this was a factory installed feature. I think the terminal for attaching the operator set are on the left, the four terminals on the cabinet wall, it was an AST instrument.
I see what looks like a buzzer mounted on the inside left? Or is this a condenser for the operator station? [PS: Given the location, I'd say it's a condenser.]
Somewhere there should probably be a key to toggle the generator source from local to remote feed. Is that a key on right or a jack?
Some wires are broken off from their terminations on the drops it seems.
#5 connecting circuit ring-off drop. brown or orange wire.
I think I have to modify my observation about the missing resistor on the 104A coil. I think this is an earlier version which had the extra A-terminal resistance implemented in the coil by means of a non-inductive winding. This can be seen by the fact that the A-terminal actually has a lead going into the coil. The compensation is between A and C. In this application it therefore seems wrong that the A-terminal would have the wire connected and not C.
It is also interesting to note that the wires terminated on the 101A do not have spade lugs, but are bare wires. Perhaps the unit was upgraded from a hardwired 113 coil?
I am wondering now who made this board. The 104A coil appears to me made by Western Electric, not NE. But if the coil was an upgrade, could someone have used WE parts?
Hmm, is a four-conductor mounting cord enough to connect an LB-AST operator instrument to this switchboard?
Quote from: unbeldi on July 18, 2014, 11:05:43 AM
I think I have to modify my observation about the missing resistor on the 104A coil. I think this is an earlier version which had the extra A-terminal resistance implemented in the coil by means of a non-inductive winding. This can be seen by the fact that the A-terminal actually has a lead going into the coil. The compensation is between A and C. In this application it therefore seems wrong that the A-terminal would have the wire connected and not C.
It is also interesting to note that the wires terminated on the 101A do not have spade lugs, but are bare wires. Perhaps the unit was upgraded from a hardwired 113 coil?
I am wondering now who made this board. The 104A coil appears to me made by Western Electric, not NE. But if the coil was an upgrade, could someone have used WE parts?
Hmm, is a four-conductor mounting cord enough to connect an LB-AST operator instrument to this switchboard?
My suspicion is that the 104A is a retro fit. Why would they have mounted it in the middle of the back side? It probably was a No. 13 sidetone coil (not 113) mounted on the base board and the harness needed to be this long to reached down there. For that, a four-conductor mounting cord was ok, just like a 315-type subset. This would also not require a condenser, and the black box indeed would be a buzzer.
Perhaps there is some evidence of two old screw holes in the base board corner?
Quote from: unbeldi on July 18, 2014, 11:05:43 AM
I am wondering now who made this board. The 104A coil appears to me made by Western Electric, not NE. But if the coil was an upgrade, could someone have used WE parts?
Hmm, is a four-conductor mounting cord enough to connect an LB-AST operator instrument to this switchboard?
I suspect NE, but who knows. Not enough is marked in it.
The original operator's set used with this I suspect was a dial-less 211 - the leads come out the left hand side through a hole and around that hole is the familiar screw pattern of a 211 mount.
Dave
Quote from: unbeldi on July 18, 2014, 12:07:00 PM
Perhaps there is some evidence of two old screw holes in the base board corner?
Not a mark at all. The only holes in the board are filled (as in used).
Dave
Quote from: DavePEI on July 18, 2014, 12:13:14 PM
I suspect NE, but who knows. Not enough is marked in it.
The original operator's set used with this I suspect was a dial-less 211 - the leads come out the left hand side through a hole and around that hole is the familiar screw pattern of a 211 mount.
Dave
NE marked their coils MM-DD-YY, not quarter-Year.
I think the "original" operator station was undoubtably a desk stand, but many switchboards indeed were retrofitted with the hanging types on the side to remove clutter from the desk. Perhaps this happened the same time the coil was installed.
Quote from: unbeldi on July 18, 2014, 12:23:58 PM
Quote from: DavePEI on July 18, 2014, 12:13:14 PM
I suspect NE, but who knows. Not enough is marked in it.
The original operator's set used with this I suspect was a dial-less 211 - the leads come out the left hand side through a hole and around that hole is the familiar screw pattern of a 211 mount.
Dave
NE marked their coils MM-DD-YY, not quarter-Year.
I think the "original" operator station was undoubtably a desk stand, but many switchboards indeed were retrofitted with the hanging types on the side to remove clutter from the desk. Perhaps this happened the same time the coil was installed.
Did you have a peek inside the one at the show to see how it was equipped?
I should point out that very few connections in the board use spades - most are connected directly to the terminals - and some directly soldered.
Dave
What would the terminal board in the bottom left of the case be for?
Dave
Quote from: DavePEI on July 18, 2014, 12:28:03 PM
Did you have a peek inside the one at the show to see how it was equipped?
Dave
No, don't recall.... but I remember revisiting it with my camera. I suppose you could contact the owner, I don't recall who it was, but I am sure others do.
Quote from: DavePEI on July 18, 2014, 12:56:01 PM
What would the terminal board in the bottom left of the case be for?
Dave
Good question, I have been peeking at it too. Six pairs. Tracing the wires would probably tell a story.
Quote from: DavePEI on July 18, 2014, 12:28:03 PM
I should point out that very few connections in the board use spades - most are connected directly to the terminals - and some directly soldered.
Dave
I would expect that actually. The terminals with the large nuts are meant for direct wire connections. But in the case of the induction coil, if it were original, I think they would have put spades there. The 315H/J/etc. subsets used spades only on the generator. The whole harness was soldered together.
Quote from: unbeldi on July 18, 2014, 01:00:08 PM
Quote from: DavePEI on July 18, 2014, 12:28:03 PM
Did you have a peek inside the one at the show to see how it was equipped?
Dave
No, don't recall.... but I remember revisiting it with my camera. I suppose you could contact the owner, I don't recall who it was, but I am sure others do.
It was Keith Hlavac, Paul Axman told me - I emailed Keith, but haven't heard back from him...
Dave
Quote from: unbeldi on July 18, 2014, 01:07:50 PM
Quote from: DavePEI on July 18, 2014, 12:28:03 PM
I should point out that very few connections in the board use spades - most are connected directly to the terminals - and some directly soldered.
Dave
I would expect that actually. The terminals with the large nuts are meant for direct wire connections. But in the case of the induction coil, if it were original, I think they would have put spades there. The 315H/J/etc. subsets used spades only on the generator. The whole harness was soldered together.
Anyway, I was just back over looking at it, and I see no sign of any other mounting point. No spare holes, nothing...
Gotta g back over for a while and glue that other spot between the boards I couldn't get this morning.
Dave
Yes, that is a buzzer on the left hand side and not a capacitor. I just removed its cover. No markings, though... Found another place I had neglected to re-glue, so have that spot done, too.Also removed the sticker residue over the 211 mount. I will hav e to convert one of my spare 211s back to non dial then try to remember how to hook them up as a simple stand. Its been a very long time since I did that. Hopefully I can find dial cover for it to close the dial mount hole.
I still have to re-solder that drop wire, but that is minor - just a matter of remembering to do it :D
Tomorrow, I will begin its refinishing.
Gotta pick up some dowel - the top drops over 4 short dowels then has two screws which actually hold it to the board. Since both the dowels are missing, the old dowels must have gone AWOL along with the top. There are mating holes in the sides.
Dave
This is not like wiring a simple stand, unless the induction coil in this board is used simply like a No. 13 coil, and that does not appear to be the case, because the A terminal is wired. I like to speculate that not many collectors have ever wired a C or G-mount for pure LB service with AST operation.
It should probably resemble something like this diagram.
This is based on a 307 set. The 307 is a common-battery signaling circuit, and therefore must have the caps.
I think for LB operation the capacitors could just be bridged with wires, unless there is a need for the higher impedance that caps provide. This is unlikely for the 0.5MF cap, since it already has the 300 ohm resistance between A and C.
The hook switch contacts are designated HS1 through HS3. HS1 would be taken care of by the front panel key, so HS2 and HS3 must be implemented in the telephone. Now you have to figure out if all this can be done with only four wires in the mounting cord.
Battery power could be applied directly from the front panel key too, so the handset operation only needs three wires. The A-terminal connection is the same as the red handset wire, so nothing is needed. So, it seems indeed one would only needs three conductors. HS2 can be served by the hookswitch, as could HS3 in principle, it could be moved to the black transmitter lead. It would be best to use the hook switch for HS3 in fact, so that the transmitter doesn't use power when the operator hangs up, but didn't disconnect her station on the switchboard.
Quote from: unbeldi on July 18, 2014, 04:00:42 PM
I like to speculate that not many collectors have ever wired a C or G-mount for pure LB service with AST operation.
Maybe not by collectors, but 211As (non dial G handset mtg + handset) were often attached to 415H and 400K Subsets in the field.
Quote from: poplar1 on July 18, 2014, 04:11:08 PM
Quote from: unbeldi on July 18, 2014, 04:00:42 PM
I like to speculate that not many collectors have ever wired a C or G-mount for pure LB service with AST operation.
Maybe not by collectors, but 211As (non dial G handset mtg + handset) were often attached to 415H and 400K Subsets in the field.
Yes, sure. I agree with that. The configuration was certainly useful.
Quote from: poplar1 on July 18, 2014, 05:51:55 PM
4 wires from telephone to subset (or switchboard) and a 4-contact switch hook are sufficient for Anti-sidetone with Magneto Service.
Yes, I thought my explanations showed that.
Turns out, that the 400K subset seems to include the 0.5MF capacitor, at least acc. to a diagram I found, but I am not quite sure about the reason. It must have something to do with balancing line capacitance, not just impedance.
I posted schematics for the 400K in another thread: http://www.classicrotaryphones.com/forum/index.php?topic=12301.0 (http://www.classicrotaryphones.com/forum/index.php?topic=12301.0)
It's essentially the same as my diagram here.
As of this morning, I have the first coat of Howard's Walnut Restor-A-Finish on my board. All loose joints are re-glued and it is beginning to look great! A few more coats of Thompson's, and a few applications of paste wax, and it will look like new!
I also found and installed a magneto crank on it.
Not bad for a free cordless board with no shipping cost!
Dave
Quote from: DavePEI on July 18, 2014, 08:37:32 PM
Ok, here is something which may lead to a definitive answer as to the origin on this board.
As I had mentioned, there is very little marked inside the board. But just about everything is Western/Northern Electric style. We do know a very similar board was made by NE due to Keith's NE board...
BUt I have discovered one number which may be a clue? It is located on the frame surrounding the keys on the back of the door. It is T 75023 G3 - anyone see any significance to this?
Dave
This stamp looks awfully modern. Like a refurbishing stamp. Could it be Jan 23, 1974?
Since someone applied it there must be some significance. It was applied with a rubber stamp by hand, from the varying thickness of characters.
Quote from: DavePEI on July 19, 2014, 08:16:27 AM
As of this morning, I have the first coat of Howard's Walnut Restor-A-Finish on my board. All loose joints are re-glued and it is beginning to look great! A few more coats of Thompson's, and a few applications of paste wax, and it will look like new!
I also found and installed a magneto crank on it.
Not bad for a free cordless board with no shipping cost!
Dave
Is the generator still strong enough to ring a phone? Did you measure its output?
Is that a No. 47 or 48 generator? Those were the largest WE/NE made, I believe, for heavy loads.
Quote from: unbeldi on July 19, 2014, 09:08:28 AM
Quote from: DavePEI on July 19, 2014, 08:16:27 AM
As of this morning, I have the first coat of Howard's Walnut Restor-A-Finish on my board. All loose joints are re-glued and it is beginning to look great! A few more coats of Thompson's, and a few applications of paste wax, and it will look like new!
I also found and installed a magneto crank on it.
Not bad for a free cordless board with no shipping cost!
Dave
Is the generator still strong enough to ring a phone? Did you measure its output?
Is that a No. 47 or 48 generator? Those were the largest WE/NE made, I believe, for heavy loads.
I didn't measure its output, but it rings phones no problem. It is an NE 48A - decal on back side bottom edge of generator. Magnets are a bit out of line, and I suspect its output will improve more when I line them up. I have noticed that before in other sets - they tend to slip in the retainer at the bottom of the magneto frame if it isn't bolted in securely.
I got the first coat of stain on it a while ago, and made up the temporary Birch plywood top for it, got the dowels and screws in. I still have to take the top over here and round its edges and sand it, but it is looking better with a top. My router is over here and I wanted to try to match the stain colour first before I bothered. Perhaps tonight...
Pi will all require light sanding between stain and paste wax coats. There are some areas I will have to re-stain to get the colour consistent. Of course, the stain is still wet in this photo, so it will even out as it dries. Looks much better later in the evening when it dried completely.
Dave
As we have so far been unable to ascertain the board's maker, I though I would mention this.
I had previously thought it was a "This Side Up" symbol, but on the outside of the board, at the center top, there is a thick blackarrow inside a "C". Does this lead towards any determination of a manufacturer? It is not a symbol I am familiar with.
I have decided to varnish the board rather than using paste was. I love the finish a paste was gives, but the varnish gives a much more resilient finish, so I have decived to go with it. I finished staining last night (other than the top which I still need to route the edges on), and will be putting on the first coat of varnish this morning....
Dave
Quote from: DavePEI on July 20, 2014, 05:08:55 AM
I had previously thought it was a "This Side Up" symbol, but on the outside of the board, at the center top, there is a thick blackarrow inside a "C". Does this lead towards any determination of a manufacturer? It is not a symbol I am familiar with.
A TCI posting by Steve C. reminded me of this. When I was young, I used to see this symbol on Canadian military goods - it meant "Canadian Issue". I haven't seen that mark since I was a child, and I had totally forgotten about it and what it meant. It was called a Broad-arrow "C". I knew it looked familiar and for that reason, I was hoping it might direct us to a manufacturer.
You would often see the logo on things like gun stocks of guns issued to soldiers.
So, while we may not have learned anything about manufacturer of the board, we have learned something about its history, that it was manufactured during WWII (See date on coil) for the Canadian Military. So it becomes just an interesting little tidbit about the board's history.
Neat, though...
Dave
Update: As the stain looked like it could use some more drying time, I decided to go ahead with the temporary lid for the board... All four edges had to be rounded over with a router bit. As I did it, the bit broke - the rotary bearing on the bottom of the bit which guides it broke off, allowing the bit to dig into the wood.
As a result, the edge was much more uneven than it should be. Before the good hardwood for the final top arrives, I will have to buy a new bit. The bad edges were cut off, with the result the temporary lid won't have the overhang on the sides the final lid will have, but otherwise it will look and function fine.
I got it sanded smooth this evening, and got it stained. With luck the more porous Birch plywood making up the temporary lid will soak in the stain faster than the close grain of the board itself, and I should be able to begin varnishing the whole board in the morning.
Once I get the board done, I will begin restoration on the Police and the fire call boxes which also came in this batch. I also have the little Stanley & Patterson anunciator which came in the latest batch I want to work on, as well as the Russian Princesses :)
Dave
Keith Hlavacs has the twin to my switchboard down to all details including the broad-arrow C on the back, matching dates, etc.
Keith has just sent me the following scans of the diagrams on the underside of his top cover. Mine, of course is missing these, as the cover was missing.
In a subsequent email, Keith told me he may try doing it on a machine they have at work to see if he can get better results.
Here are copies of his scans. If I can improve them later, I will. I am in the museum workshop right now working on the board. I will see later if I can improve the scans.
Dave
Certainly answers a lot !
The 104A induction coil is original by design and it was supposed to have a 211 hangup telephone on its side!
Even with some corrections, the diagram is still pretty hard to read, as far as text is concerned. It would have been great if Keith had laid it on a scanner since the it's the top board from what I understand that can be removed entirely.
Here is the operator telephone set circuit acc. to the diagram.
Terminals are drawn as close as possible to the diagram. In a circuit diagram this is sometimes a little difficult, but worked out ok.
1, 2, 3, 4 are connection terminals for the OPR TEL SET on the inside wall. Most of the internal terminals inside the G1/211 are there too.
Essentially it is identical to the diagram I drew earlier here based on a 307. The capacitors are not needed in this application, and we see that NE left them out too.
This circuit was also used in the 400K subscriber set for use with a D1/202H, see circuit description here: http://www.classicrotaryphones.com/forum/index.php?topic=12301.0 (http://www.classicrotaryphones.com/forum/index.php?topic=12301.0)
Quote from: unbeldi on July 18, 2014, 01:01:35 PM
Quote from: DavePEI on July 18, 2014, 12:56:01 PM
What would the terminal board in the bottom left of the case be for?
Dave
Good question, I have been peeking at it too. Six pairs. Tracing the wires would probably tell a story.
I think the diagram tells me that this 31A connecting block on the base is for expanding the switchboard.
The twelve conductors form a sort of 'bus' that is common to all line circuits, and thus can be extended to another board to operate 20, or even more, magneto lines on the same five talk circuits.
Block diagram of circuit parts:
Quote from: unbeldi on July 22, 2014, 12:23:05 PM
I think the diagram tells me that this 31A connecting block on the base is for expanding the switchboard.
The twelve conductors form a sort of 'bus' that is common to all line circuits, and thus can be extended to another board to operate 20, or even more, magneto lines on the same five talk circuits.
Hmm, looking over the board pics again, it seems to me that none of the talk circuit drops were wired completely in this board. There is always one lead missing, and a wire appears to be stored in a sleeve close by. I think this is exactly the kind of thing one would do when the intent is to use the board as an extension board to another unit. You wouldn't want two drops falling, and having to restore them, for every termination.
Quote from: unbeldi on July 22, 2014, 02:37:09 PM
Quote from: unbeldi on July 22, 2014, 12:23:05 PM
I think the diagram tells me that this 31A connecting block on the base is for expanding the switchboard.
The twelve conductors form a sort of 'bus' that is common to all line circuits, and thus can be extended to another board to operate 20, or even more, magneto lines on the same five talk circuits.
Hmm, looking over the board pics again, it seems to me that none of the talk circuit drops were wired completely in this board. There is always one lead missing, and a wire appears to be stored in a sleeve close by. I think this is exactly the kind of thing one would do when the intent is to use the board as an extension board to another unit. You wouldn't want two drops falling, and having to restore them, for every termination.
My gosh, you have good eyes! I have the board here and didn't even notice that. Easy fix, though.... Been concentrating too much on refinishing it... The two front border pieces are proving to be quite a problem getting an even finish on. I The rest turned out fine....
This part was more weathered than the rest of the board, causing the boards to be rougher on the surface. I think I will strip them down again and give them a really good sanding...
Dave
Quote from: DavePEI on July 22, 2014, 03:48:18 PM
My gosh, you have good eyes! I have the board here and didn't even notice that. Easy fix, though.... Been concentrating too much on refinishing it...
...
I am not distracted by all the work you're putting in. I am an armchair investigator, LOL, picking out only the things that interest me from time to time.
Here is the latest photo of the board after re-gluing and refinishing. Still a coat or two of paste wax to go, but it gives an idea of what it looks like now... I have gone for the original look rather than trying to lighten it up. 211 mounted on left hand side.
Dave
Quote from: DavePEI on July 23, 2014, 01:53:32 PM
Here is the latest photo of the board after re-gluing and refinishing. Still a coat or two of paste wax to go, but it gives an idea of what it looks like now... I have gone for the original look rather than trying to lighten it up. 211 mounted on left hand side.
Finally, 3:00 P.M. Jul 24th, the switchboard is done and tested. I used a pair of 3.5 Vdc cellphone switching supplies in place of the battery. I haven't checked every function of course, but everything that matters seems to work.
What a nasty job re-soldering those drop wires - there's so little to solder to and with my poor eyes it took quite a while. But another project completed, and on to others! It is a nice little rare board, and required quite a bit of work to the case, at least, as well as the wires broken off the drops. I have moved it to the museum room it is going to be displayed in.
Dave
So, exactly what is working? Are you going to wire some magneto telephones to it permanently?
Do the drops work when you crank a phone? How about those talk circuit drops?
Does the buzzer work?
:-)
Quote from: unbeldi on July 24, 2014, 06:50:28 PM
So, exactly what is working? Are you going to wire some magneto telephones to it permanently?
Do the drops work when you crank a phone? How about those talk circuit drops?
Does the buzzer work?
:-)
All of the above work, but with only one phone wired into it in the workshop. So that's why I can't yet say it is performing flawlessly, until I get it loaded down with phones.
I will eventually connect all the magneto phones in the demo room to it, but no rush for that - too many other projects in line. At least it is now ready and I can get on with more of the stuff I have received lately!
Dave
Congratulations!
Here is a PDF file containing the Dwg for the C-190 Cordless Switchboard as received from Keith Hlavacs this morning. He has exactly the same board as I have...