[GreenKeys] M28 ASR Print Issue

W2HX w2hx at w2hx.com
Tue Jun 4 19:25:51 EDT 2024


Yes mine has a relay. It is operated by the main line. Then a local supply (within the lesu) operates the page printer. 
I'll check the bias. I think this relay is not an adjustable one (it doesn’t appear to be, but I could be wrong). But bias is the first thing I'll check.



73 Eugene W2HX
My Youtube Channel: https://www.youtube.com/@w2hx/videos
 

-----Original Message-----
From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net> On Behalf Of John, W9DDD
Sent: Monday, June 3, 2024 11:18 PM
To: greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] M28 ASR Print Issue

So does your LESU have a line relay in it?  Mine does.  I'd like to bypass it, but it is involved in a function that I find useful.  So maybe the line relay has become maladjusted?  Or if a mercury wetted one maybe on way to failure?  A lot of guessing on my part of course?


On 6/3/2024 7:59 PM, W2HX wrote:
> Ok Thanks everyone for the input and suggestions. I'll do some lubrication, I'll check range finder settings etc.
>
> One thing I should mention, the KSR has the selector magnets directly on the loop. The ASR has a LESU between the external loop and the page printer.
> Could this be a bias adjustment issue?
>
> Here is the real problem I'm facing. If I send RYs or QBF, both printers work the same (perfect copy). However, in real-world situations (off the air) they are far from the same. The ASR has a much worse copy. Even though they are using the same TU (CV-2460) to convert the audio to loop current, and the loop by definition, has the same traffic (and signalling characteristics) for both printers, the ASR is much worse.
>
> I have not been able to duplicate the problem using the character generator EXCEPT when doing dot cycles. And if this is not a valid test for page printers then I can't really reproduce the problem.
>
> This isn’t 100% true. I have recorded audio from some past RATT sessions that I can use. I will note that in the past, I have attempted to use those off-the-air recordings and use the range adjustment to produce better copy. It never really was conclusive. I was hoping to generate the loop traffic locally to have a more controlled environment.
>
> Perhaps I should try to introduce some distortion on the loop to see how sensitive the ASR is to this, and try to compensate somehow with the range finder. Not sure...
> Ok more work to do here. Thanks everyone!
>
>
> 73 Eugene W2HX
> My Youtube Channel: https://www.youtube.com/@w2hx/videos
>   
>
> -----Original Message-----
> From: greenkeys-bounces at mailman.qth.net 
> <greenkeys-bounces at mailman.qth.net> On Behalf Of John, W9DDD
> Sent: Monday, June 3, 2024 7:21 PM
> To: greenkeys at mailman.qth.net
> Subject: Re: [GreenKeys] M28 ASR Print Issue
>
> My impression is that dot cycle is designed to test a circuit for bias.
> Square wave in and hopefully square at the other end of the line.   The
> QBF and RY are for testing terminal equipment.
>
> One normally would think of the dot cycle being a square wave with no bias.  (can't tell from the panel controls if it provides for putting a bias in the dot cycle.)  On the other hand the test signal QBF etc on older tests (and I assume this one too)  allowed you to introduce all different kinds of bias to test the terminal's ability to deal with them.
>
>
> On 6/3/2024 5:14 AM, Nick England wrote:
>> Yes to the range adjustment.
>>
>> Note that “dot cycle” or “reversals” is NOT the same as RYRY.
>> Reversals 01010101010101
>> RYRY. 0101011/0010101/
>> (/just to show characters)
>>
>> Depending on the machine it might print RYRY for reversals or might 
>> not. I suspect 7 vs 7.42 speed makes a difference but haven’t 
>> bothered to verify that.
>>
>> Anyway set the range control with real RY characters, not reversals.
>>
>> Reversals are great for adjusting polar relays and transmission 
>> circuits, not printers.
>>
>> Nick England K4NYW
>> www.navy-radio.com <http://www.navy-radio.com>
>>
>>
>> On Sun, Jun 2, 2024 at 10:13 PM Duncan Brown 
>> <duncanancy at earthlink.net <mailto:duncanancy at earthlink.net>> wrote:
>>
>>      Eugene,
>>
>>      With the "Dot cycle" signal, you are generating a short stop pulse
>>      (22ms).
>>
>>      Check the motor speed and the Range control.  You can probably get
>>      it to print correctly with a Range adjustment.  If the Range
>>      setting is much different than the other unit, it indicates
>>      another problem.
>>
>>      Good luck,
>>
>>      Duncan
>>      K2OEQ
>>
>>
>>
>>      On 6/2/2024 10:04 PM, W2HX wrote:
>>>      Thanks Jeff. They both used to work 100% in sync a few years ago.
>>>      This is something that has changed in the last few years.
>>>
>>>      One thing I’ll do is put the character generator on a scope (in
>>>      series with a voltage source) to see what exactly is the
>>>      difference between setting two characters of R and Y vs. dot cycle.
>>>
>>>      As you suggested, I just tried the dot cycle on the ASR only
>>>      (removing the KSR) and still had the same result RYYRYY.
>>>
>>>      I should also mention that, the rhythm of the machine sounds
>>>      “off” almost like it is running faster than 45 baud. Not much
>>>      faster, but just sounds off. It used to be when I ran both
>>>      machines together, they audibly would be perfect. Now the ASR
>>>      sounds like it is running a little faster. That is the only thing
>>>      I can think of to describe the sound.
>>>
>>>      73 Eugene W2HX
>>>      My Youtube Channel: https://www.youtube.com/@w2hx/videos
>>>
>>>      *From:*Jeffrey Golas <jeffg at junknet.net> <mailto:jeffg at junknet.net>
>>>      *Sent:* Sunday, June 2, 2024 9:56 PM
>>>      *To:* W2HX <w2hx at w2hx.com> <mailto:w2hx at w2hx.com>
>>>      *Cc:* Greenkeys <greenkeys at mailman.qth.net>
>>>      <mailto:greenkeys at mailman.qth.net>
>>>      *Subject:* Re: [GreenKeys] M28 ASR Print Issue
>>>
>>>      Id compare selector magnet resistance/inductance, the repeating
>>>      letters aImost seem like a signal issue than mechanical. Id also
>>>      try an RY paper tape by itself (or try your tester on just that
>>>      machine).
>>>
>>>      I wonder if one is intended for a different current rating or has
>>>      any resistors on the loop that are aging or just too large.
>>>
>>>      Jeff
>>>
>>>
>>>
>>>          On Jun 2, 2024, at 9:37 PM, W2HX <w2hx at w2hx.com
>>>          <mailto:w2hx at w2hx.com>> wrote:
>>>
>>>          
>>>
>>>          Hi all,
>>>
>>>          For the last several years, I’ve noticed that my ASR does not
>>>          print traffic the same as my KSR both are on the same loop. I
>>>          would say the accuracy of the print is much worse than the
>>>          KSR. But since I had the KSR working well, I never had the
>>>          impetus to look into in detail. Tonight, I did a simple test
>>>          and saw some interesting results.
>>>
>>>          First, I am using a character generator which seems to work
>>>          well (see attached picture).  The character generator has
>>>          several modes, QBF (sentence) is one mode, then you can set
>>>          up two individual characters and send an alternating series
>>>          of these characters. It also has a “dot cycle” mode, which I
>>>          believe is simply alternating mark and space.
>>>
>>>          When I set up R and Y and send them out, both printers work
>>>          perfectly. However, when I use the DOT CYCLE mode, the KSR
>>>          again works FB, but the ASR shows RYYRYYRYY. Below are links
>>>          to the print copy. Note there are two “paragraphs” on the
>>>          page. The top paragraph is using the individual R and Y
>>>          characters set up using toggle switches. The second paragraph
>>>          shows the results of the DOT CYCLE mode. Again, these are on
>>>          the same current loop.
>>>
>>>          KSR page:
>>>          
>>> https://w2hx.com/x/What-Is-It/ASR-Printing-Issue/20240602_191335.jpg
>>>
>>>          ASR page:
>>>          
>>> https://w2hx.com/x/What-Is-It/ASR-Printing-Issue/20240602_191352.jpg
>>>
>>>          Anyone have any suggestions where to look?
>>>
>>>          Thanks
>>>
>>>          73 Eugene W2HX
>>>          My Youtube Channel: https://www.youtube.com/@w2hx/videos
>>>
>>>          <20240602_191208.jpg>
>>>
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>>>>>>      Jordan Spencer Cunningham's GreenKeys Search Tool:https://teletype.net/gksearch
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>>>>> Jordan Spencer Cunningham's GreenKeys Search Tool:
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>>>>> 1998-to-2001 greenkeys archive:
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> --
> ---
> ----
> The above comments or recommendations are SWAG. Use at your own risk.
>
> John, W9DDD
>
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>>>> Jordan Spencer Cunningham's GreenKeys Search Tool:
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>>>> 1998-to-2001 greenkeys archive:
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>>>> 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 
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>>>> Jordan Spencer Cunningham's GreenKeys Search Tool: 
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>>>> 1998-to-2001 greenkeys archive: 
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>>>> 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 
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--
---
----
The above comments or recommendations are SWAG. Use at your own risk.

John, W9DDD

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>>> 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

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