[GreenKeys] Model 19 parts and questions

[kh-phillips at 9-5usa.org]

Thanks to everyone who has replied.  This is definitely one of the (if not
"the") most helpful lists I have belonged to.

To respond to an earlier reply asking about any military designations on
this set, there really are none that I can see.  The reperforator cabinet
has TT-16/FG on it but that may not mean much.  My understanding from
talking to the Seller is that he pieced together this set over time.  The
case/cabinet of the printer itself has probably been re-painted (to a
lighter battleship grey) and the Teletype Corporation insignia removed. 
According to the Seller, this was a M.A.R.S. outfit that he acquired and
restored.

73
Kevin


> The rectifiers supplied with the Model 19 can be used for a "local loop".
> They also supply power to the keyboard punch and bias
> voltage current to the line relay. The line relay is wired to use the
> power
> supply to then key an internal loop for the printer.
> The actual signal "loop" is provided externally in a
> standard configuration. If the wiring is "stock" then there should
> be a connection at the polar relay's contacts that can be shorted, thus
> creating the "local loop". If the polar relay is removed, the socket
> contacts for the relay's common and MARK/SPACE contacts can be
> jumpered out. (This holds true for any "stock" TTY, by the way.)
> In fact, if a milliameter is placed in the correct contact positions, the
> machine
> should lock up and the loop current can be read.
> I would caution that the supply be tested for
> good DC since the rectifier and caps are pretty old. Ripple on the DC
> would definitely
> impact the performance of the mahcine if the supply is used to provide
> the loop voltage.
> Wiring diagrams for the Model 19 are in the "New RTTY Handbook" by
> Byron Kretzman and the TAB "RTTY Handbook" by Wayne Green.
>
> 73,
> Jack K0TTY
>
> NNNN
>
> -------------- Original message from WA5CAB at cs.com: --------------
>
>
>> Kevin,
>>
>> It's been far too many years since I last played with an M15 or M19 to
>> answer
>> most of your questions so you'll have to wait for someone with more
>> recent
>> experience to speak up. But I can answer your questions about the RA-87.
>> Yes,
>> it is the DC loop supply. And although odds are that you need to add at
>> least
>> one jumper to close the loop for the printer and probably some others to
>> put
>> the keyboard in series with the line printer (as the machine would
>> normally
>> have been connected into external circuits), odds are also that the
>> RA-87 isn't
>> working.
>>
>> First, it has filter capacitors that may need to be replaced (not really
>> a
>> big deal other than finding something that fits mechanically). Second,
>> it uses
>> a selenium rectifier and odds are almost 100% that it is bad. Selenium
>> rectifiers turned out to have a 30-50 year shelf and service life (fact
>> not
>> known
>> when they were new). So it needs to be replaced with a silicon
>> rectifier.
>> Until that is done, I would unplug the AC cord for the RA-87.
>>
>> Also, if the 19 set has a rectifier with an RA-87 or RA-87-A nameplate,
>> it's
>> may be a military set. Look around for a nameplate or nameplates for the
>> set
>> or the other components. Something beginning with TT, TG or AN/FGC for
>> example. If you can locate anything like that, it's possible one of us
>> may have
>> the
>> TM 11 on that particular set.
>>
>> In a message dated 8/22/2008 11:12:19 AM Central Daylight Time,
>> kh-phillips at 9-5usa.org writes:
>> > First for the parts, I need the cord that pulls the carriage back on
>> the
>> > return. The second part I need is, I think, one of the Y-levers. It is
>> > the longest one. I hate to admit it but in my ham-fisted attempts to
>> > get the thing running I got the carriage off track and ended up with
>> the
>> > couple of broken parts (that I know of).
>> >
>> > The set has been sitting unused for 35-40 years in a house which had
>> > been closed up but still had utilities connected and running. The man
>> > who sold it really thought it would still be in operating condition.
>> > The AC has been kept on in the house but this was in south Louisiana
>> so
>> > the humidity level, even with AC, is much higher than anyplace else!
>> > The set has a Signal Corps RA-87 Rectifier. I had to replace the DC
>> > cord. The machine runs but is running open. The bars under the
>> > carriage just vibrate back and forth. (I'm new to teletype so I'm not
>> > familiar, yet, with a lot of the terms.) The tape punch works fine but
>> > the keys on the carriage do not operate whenever a key is pressed on
>> the
>> > keyboard.
>> >
>> > One question I have is whether or not the 60ma loop is being supplied
>> by
>> > the RA-87? Second question is, assuming the loop is supplied by the
>> > RA-87, what/where should I check to get the thing to run closed?
>> >
>> > One DC socket on the power supply has apparently gone dead. The other
>> > is still active but the plug doesn't fit well at all. I'm tracking
>> down
>> > some schematics and may try to have the PS rebuilt.
>> >
>>
>> Robert & Susan Downs - Houston
>> wa5cab dot com (Web Store)
>> MVPA 9480
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