[GreenKeys] Current loop not providing (enough) current

Fri Sep 27 19:17:04 EDT 2019

Got it! 

Reset the screw doohicky to the original position. Also I did not know about the range finder. It doesn't seem to make a difference where it is set, it was at 40 when I got the machine.

Right now the coils are one onto another and 1-3 measure 52mA and 2 and 4 also measure 52mA so assuming. 8mA is dropping somewhere between the power supply and the coils. I don't think this would be enough to put a kabosh on the whole thing but maybe? 

I could possibly lower my 2k resistor down to maybe 1.8k on the loop, and see if that pushes it up to 60 at the coil? Though, before doing that I'm going to take the PC board back out of the loop and see if maybe that makes a difference at the coils.

 Like I had shown in the once picture, I can see no other way I'm not great with series/parallel when it comes to coils, not sure why it's so hard for me to grasp but I'm 80% certain this is in series not parallel. 

Thank you everyone so far for your advice and encouragement, I'm sure I'll get this eventually, and I'm learning which is even better!

From: steve.n4tty at gmail.com
Sent: 27 September 2019 13:38
To: paul0926 at comcast.net; shardsofaperture at gmail.com
Cc: greenkeys at mailman.qth.net
Subject: RE: [GreenKeys] Current loop not providing (enough) current

I agree with Paul.  I would make sure of the current and the proper wiring way before making adjustments with the magnets.  Unless you have the maintenance book that tells you the EXACT distance the poles of the magnets should be from the armature.

Steve G./N4TTY

From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net>On Behalf Of Paul Heller
Sent: Friday, September 27, 2019 12:23 PM
To: Zach Zarzycki <shardsofaperture at gmail.com>
Cc: GreenKeys <greenkeys at mailman.qth.net>
Subject: Re: [GreenKeys] Current loop not providing (enough) current

Zach,

I believe you have it backwards. The relay should be energized and the during the stop bit and should open on the start bit.  From the way I read your email, you are looking at it the other way around. Maybe I misread your email.

Once you start changing the distance of the relays you can get into a real problem that is very hard to fix. I’d avoid that at all costs.

It sounds like there is not enough energy in the coils to close the relay. Are you still in a low current situation or have you resolved that problem? Depending on how the magnets are wired (parallel or serial) you need to be at 60ma or 30ma. Maybe try wiring for 30ma?

Paul
W2TTY

ITTY:                      HTTP://INTERNET-TTY.NET:8000/ITTY
AUTOSTART: HTTP://INTERNET-TTY.NET:8030/AUTOSTART
EUROPE:              HTTP://INTERNET-TTY.NET:8040/EUROPE

On Sep 27, 2019, at 4:24 PM, Zach Zarzycki <shardsofaperture at gmail.com> wrote:

Yeah, not sure why if it autocorrected DMR but that was me!

I'm wondering if it's mechanical and the armature needs to be closer to the magnet to sense the start bit?   

From: steve.n4tty at gmail.com
Sent: 27 September 2019 10:06
To: shardsofaperture at gmail.com; greenkeys at mailman.qth.net
Subject: RE: [GreenKeys] Current loop not providing (enough) current

Zach,

From watching your video it looks to me as if the following is happening:
1. You manually move the magnet armature against the magnet and the magnet
has enough current to hold the armature in the mark condition.
2. You then press any key and the "start bit" opens the circuit so the
machine starts running open until you manually move the armature again.  In
other words the magnets are not pulling the armature back to the mark
condition.
3. At one point you adjusted a screw that stopped the running open and even
pressing a key would not start it running open again, even though you could
see the magnet release the armature when a key was depressed.  Not sure what
that screw is since I have never seen the model TTY you are working with.  I
would say return that screw to it's original adjustment, as I don't think it
is a part of your issue at all.  It just appears to me to be keeping the
machine from sensing even the "start bit."

I haven't been following all of this thread, but did I see you, or was it
someone else, mention DMT?  If it was you, were you wanting to use DMR to
talk directly to someone?

Keep plugging away, you'll get it working eventually!

Steve G./N4TTY

-----Original Message-----
From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net>
On Behalf Of Zach Zarzycki
Sent: Friday, September 27, 2019 9:42 AM
To: GreenKeys <greenkeys at mailman.qth.net>
Subject: Re: [GreenKeys] Current loop not providing (enough) current

Removed resistor no change. The magnet is sort of working. If I push it
toward the coil, it closes and doesn't open until I press a key or hit
break. I think thats reverse. It's sort of like the magnet is always
energized and only a keypress breaks the loop, instead of the keypress
energizing the magnet. I've tried flipping polarity, I have it hooked up
just like I showed here minus the resistor https://i.imgur.com/KYAiy42.jpg
and key presses register on the computer still, but typing on the computer
and typing on the teletype doesn't cause the key to press. Best way I can
describe what is happening is everything feels backward.

Here is a video that might better show what I'm seeing is here - maybe
someone else can see something I'm not. https://youtu.be/CbZMtXkXz4w

On Fri, Sep 27, 2019 at 8:52 AM Zach Zarzycki <shardsofaperture at gmail.com>
wrote:

Well, I think as it was suggested, a resistor may be the culprit.

There is a resistor that one the one schematic is labeled as "Station

Line Resistor" with a note "when required". This is on the line relay

- switch control two wire line or line to grnd diagram. This is NOT

how I am wiring this thing up as I don't believe it is necessary for a

single unit, and involves equipment I don't have.  I've highlighted

the resistor in this photo - https://i.imgur.com/QOAsNqX.jpg and the

position of the resistor matches up on my unit here >

https://i.imgur.com/Kk8LU8i.jpg . The parts diagram shows it as a 5k

or 1050 ohm resistor  https://i.imgur.com/TXwsVbi.jpg (highlighted

yellow).

I believe I need to remove the resistor and hook everything up like

this > https://i.imgur.com/KYAiy42.jpg where the loop is in red, the

resistor in question needs removed from the spot in the drawing from

contact 26 to the sending contacts (yellow), this diagram is the

"Local Attended TWX Service, no line relay switchboard" diagram.

I'm not sure what a station line resistor is, can anyone confirm this

is safe to remove? Worth a shot?

On Fri, Sep 27, 2019 at 7:21 AM Zach Zarzycki

<shardsofaperture at gmail.com> wrote:

So there was a little operator error here, therefore, Jordan, I really

don't think the board is bad. I didn't swap my lead on the meter from v to
ma (amperage , ma are separate ports, then volts, ohms, temp, diodes and
caps on another port).

I have 60mA at the supply, between the 2 points it hooks to the PC

interface and therefore at the terminal hookups on the teletype. between two
windings down the loop on unit itself it reads 53mA, and at 2 other windings
0.

The break key and any strike does break the loop. Now it's a matter of

figuring out why the machine itself / magnet won't energize.

I'm going though the schematic again to see if coils are supposed to be

in parallel or series with the way I have the loop hooked in - thinking
about what Ralph had said with regard to reversed coils.

Ralph,  Ohio, and yeah, 40 is 2 far and my hf setup right now is awful,

antenna down and what not!
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