[GreenKeys] questions about the Model 15 wiring diagram/schematic

Thu Jul 25 14:39:03 EDT 2013

 Drat. Regarding C and my reference to a 5 ohm resistor, your diagram doesn't have a 5 ohm resistor. I'm looking a either an older or newer version of the diagram (probably older) here at home. On my diagram there is a 5 ohm spliced between the capacitor and the junction of the two 300 ohm resistors. Sorry for the confusion!

Wayne

 WB4OGM

-----Original Message-----
From: hwhall &lt;hwhall at compuserve.com&gt;
To: greenkeys &lt;greenkeys at mailman.qth.net&gt;
Sent: Thu, Jul 25, 2013 11:30 am
Subject: Re: [GreenKeys] questions about the Model 15 wiring diagram/schematic

    It's been a while since I wandered through those diagrams and they can be confusing. One thing that makes them more confusing is that there are a number of wires and parts that are provided from the factory but aren't normally connected for use by the factory. These TTY sets were built to enable flexibility in power sources and motor types plus a other "bells & whistles" that aren't connected for use by the factory but can be put to use by following the manuals (to cut jumpers, make normally unused connections and so on).

 A. The loops in the diagram indicate that wire is brought to the relay & contacts (or whatever) but not connected at the factory. It is for one of those options or adaptations not normally required. You can probably ignore them unless you are specifically enabling some feature and in that case you follow the manual's instruction for connecting.

 B. Yes, that is the motor on-off switch.

 C. I think that capacitor is part of a noise reduction feature with the 5 ohm resistor in series. I stand by to be corrected. When you are using an AC Synchronous motor, the 1MF cap and its 5 ohm resistor are connected across the motor on-off switch (a jumper in the AC Synch motor base completes that connection).

 D. Yes, the fustat (also fusetron) is an edison base screw-in fuse.

 E. If you have the full page this diagram appears on, see the NOTES and note 10. It indicates these contacts are only used when implementing an option to control the motor using the 'figures H' or 'figures M' signals. If I recall correctly, those particular keyboard inputs were used on some TTY circuits to turn on/off the motor at a remote or distant end teleprinter.

 F. This is a "convenience" power outlet. Again, if you have the full page this diagram appears on, see also the diagram labeled "Actual Wiring..." It has some additional notations and in some aspects is easier to understand the wiring when you are trying to match the diagrams to the actual devices. On your annotated diagram it looks like the receptical has a single wire running past it, but the "Actual Wiring" diagram shows the connections in a more "normal looking" way.

 Wayne
 WB4OGM

 -----Original Message-----
 From: paul &lt;paul at paulnewland.com&gt;
 To: greenkeys &lt;greenkeys at mailman.qth.net&gt;
 Sent: Thu, Jul 25, 2013 8:21 am
 Subject: [GreenKeys] questions about the Model 15 wiring diagram/schematic

       I'm new to this forum and hope I'm submitting this in the correct manner.? Apologies in advance if I've done it the wrong way.

  I have some questions about the schematic for a Model 15 TTY.?? I have a Model 15 and it runs pretty well, but I'm a small-signal person and don't understand some aspects of the schematic, and hope people here can clue me in a bit.
    ?
    First, here's an schematic (or section of the schematic) that I've annocated....? http://ad7i.net/images/model15schematicannotated-4.jpg ??I've circled sections of the schematic of interest to me and given each a letter designation for discussion purposes.

    ?
    In section A looks to be the business portion of a relay, but I'm not familiar with this type of schematic representation of a relay. ?What's the meaning of the narrow loop that comes from the left?? Is that suppose to represent the coil of the relay, and its DC resistance is 355 ohms?? What's the meaning of the wider loop coming in from the top?? If that represents the relay's contacts then what part of that loop represents the NO, NC and swinger contacts?? Also, what's the purpose of this relay?? 
    ?
    In section B, does the switch represent the front panel (right side) on/off switch?
    ?
    Is the capacitor at C the motor start capacitor?? Do these ever go bad?
    ?
    Is the FUSTAT at D the Edison socket fuse at the back left side of the base?
    ?
    At E is a connector going to something labeled "motor contacts".? Don't really understand what's that's about, since there appears to be a connection (short/shunt) between the left side of contacts 9 and 10 on that connector.? Physically where is this connector with pins number 9 & 10 in the TTY?
    ?
    At F what's the intended use for the "receptacle"?? 
    ?
    I'll be very grateful to whatever insights people might have to offer on these issues.
    ?
    73,
    ?
    Paul, ad7i

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