[GreenKeys] Model 14 keyboard adjustment

Sun Aug 6 09:43:39 EDT 2023

Thanks all, makes sense. I am using deramps adapters, and I am fairly
certain that if I can remove the deep layer of gunk/oxides/whatever that
formed over many decades of shed storage on these contacts that were open,
it will work great on the low voltage circuit.

I say that because the start bit contact works beautifully. It is the other
5 contacts that were left open to the air (were mechanically open when
stored badly) that I am having trouble with.

I bet a good shot of high voltage would help, I have a high voltage supply
out in the shed I may bring in. I expected the contact cleaner to
chemically remove the problematic materials when combined with my
mechanical cleaning, but apparently not.

-Eric

On Sun, Aug 6, 2023 at 8:33 AM Paul Heller <paul0926 at comcast.net> wrote:

> It was around 2009:
>
> [GreenKeys] why high loop voltage
> <http://mailman.qth.net/pipermail/greenkeys/2009-January/013324.html>
> mailman.qth.net
> <http://mailman.qth.net/pipermail/greenkeys/2009-January/013324.html>
> [image: favicon.ico]
> <http://mailman.qth.net/pipermail/greenkeys/2009-January/013324.html>
> <http://mailman.qth.net/pipermail/greenkeys/2009-January/013324.html>
>
>
> Paul
> W2TTY
>
> ITTY: HTTP://INTERNET-TTY.NET:8000/ITTY
> <HTTP://internet-tty.net:8000/ITTY>
> ITTY 100:  HTTP://INTERNET-TTY.NET:8010/ITTY100
> AUTOSTART: HTTP://INTERNET-TTY.NET:8030/AUTOSTART
> <HTTP://internet-tty.net:8030/AUTOSTART>
> EUROPE: HTTP://INTERNET-TTY.NET:8040/EUROPE
> <HTTP://internet-tty.net:8040/EUROPE>
>
> On Aug 6, 2023, at 7:31 AM, Paul Heller <paul0926 at comcast.net> wrote:
>
> I remember a discussion years ago where a number of folks said high
> voltage was important for the contacts. The design voltage was much higher
> than 15v. You might try a loop source that delivers higher voltage and
> 60ma. That might work better with your contacts.
>
> Paul
> W2TTY
>
> ITTY: HTTP://INTERNET-TTY.NET:8000/ITTY
> <HTTP://internet-tty.net:8000/ITTY>
> ITTY 100:  HTTP://INTERNET-TTY.NET:8010/ITTY100
> AUTOSTART: HTTP://INTERNET-TTY.NET:8030/AUTOSTART
> <HTTP://internet-tty.net:8030/AUTOSTART>
> EUROPE: HTTP://INTERNET-TTY.NET:8040/EUROPE
> <HTTP://internet-tty.net:8040/EUROPE>
>
> On Aug 6, 2023, at 7:27 AM, Jeffrey Golas <jeffg at junknet.net> wrote:
>
> 
> Dont use sandpaper! The MA is important as it does affect the waveforms.
> The machine wants to see 60ma whether it's 120vdc or 15vdc. Set the scope
> to be wide enough to get an entire character if you havent already, it
> almost looks like the pic may just be showing the stop bit (33ms?).
>
> Dial in the loop first, verify its 60ma at idle.
>
> Jeff
>
> On Aug 6, 2023, at 9:05 AM, Eric Moore <mooreericnyc at gmail.com> wrote:
>
> 
>
> https://deramp.com/downloads/teletype/Model%2015/loop%20interface%20board/Schematic%20Rev%20A.pdf
>
> Verified the printer loop at 60ma. The keyboard loop runs at 15V, not sure
> on the ma, but not sure it matters much as it just opens and closes without
> driving any coils or similar.
>
> I am fairly certain my issue is the contacts somehow. I see voltage (and
> continuity) up to those contacts, but despite cleaning fairly extensively
> with contact cleaner, they are still too high resistance. I am going to try
> some sandpaper today and see what is what...
>
> -Eric
>
> On Sun, Aug 6, 2023, 12:10 AM Gerry Block <gblock at sbcglobal.net> wrote:
>
>> typo:  "60 ma"
>>
>> Sent from my iPhone
>>
>> On Aug 5, 2023, at 10:07 PM, Gerry Block <gblock at sbcglobal.net> wrote:
>>
>> eric
>>
>> what does your loop schematic look like?  sketch it out and enclose
>> photo.
>> what is the loop power supply voltage.
>> what is the series resistance to make the 60ms.
>> are you sure it is running at 60 ms?
>> where is the scope probe grounded and where is the loop supply grounded?
>> i doubt it is the contacts.
>>
>> gerry
>>
>> Sent from my iPhone
>>
>> On Aug 5, 2023, at 5:49 PM, Eric Moore <mooreericnyc at gmail.com> wrote:
>>
>> 
>> I have cleaned with contact cleaner and paper tape pretty extensively,
>> but can always go another round.
>>
>> I do not think that is a good waveform, but similarly, no idea.
>>
>> -Eric
>>
>> On Sat, Aug 5, 2023, 7:23 PM Jeffrey Golas <jeffg at junknet.net> wrote:
>>
>>> Correct me if Im wrong but could just be "dirty"; as the cam rubs
>>> against the switch youre seeing noise like a dirty volume pot.
>>>
>>> Id use some alcohol and a business card and scrub the contacts (plus Im
>>> not sure thats even a terrible signal for a 1940s device. Going machine to
>>> machine I dont think that tiny bit of leakage woulda mattered.
>>>
>>> Again, correct if wrong, Im here learning too.
>>>
>>> Jeff KC3GJX
>>>
>>> ______________________________________________________________
>> GreenKeys mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:GreenKeys at mailman.qth.net
>>
>> Jordan Spencer Cunningham's GreenKeys Search Tool:
>> https://teletype.net/gksearch
>>
>> 2002-to-present greenkeys archive:
>> http://mailman.qth.net/pipermail/greenkeys/
>>
>> 1998-to-2001 greenkeys archive:
>> http://mailman.qth.net/archive/greenkeys/greenkeys.html
>>
>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
>> http://comcents.com/tty/greenkeyssearch.html
>>
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to gblock at sbcglobal.net
>>
>> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
> Jordan Spencer Cunningham's GreenKeys Search Tool:
> https://teletype.net/gksearch
>
> 2002-to-present greenkeys archive:
> http://mailman.qth.net/pipermail/greenkeys/
>
> 1998-to-2001 greenkeys archive:
> http://mailman.qth.net/archive/greenkeys/greenkeys.html
>
> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
> http://comcents.com/tty/greenkeyssearch.html
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to phearvada at gmail.com
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20230806/c8303ccf/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: favicon.ico
Type: application/octet-stream
Size: 2494 bytes
Desc: not available
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20230806/c8303ccf/attachment.obj>