[GreenKeys] 28ASR Selector Magnet Driver and "Blinding"

[John, W9DDD]

Good morning Robert,

Could you describe the symptoms is greater detail?  Is the printer doing 
absolutely nothing, or is there some motion going on, but no printing? 
In what position is the print suppression code bar?  If it kind of goes 
through the motions but never prints you may have a situation with  a 
similar solution to the one for the sync pulse problem. Is there a 
solenoid on the left side of the printer?

If there are no signs of anything going on then about all the documents 
about the blinding are in the link I gave you earlier off list.  I've 
never run into anything that documented the source of the blinding 
(doesn't mean it's not there is some of the Navy versions of docs).  It 
would be either stunt box contact (but I don't think blinding yourself 
really works too well), a relay or a switch since it has to be an 
isolated contact.  Any relays unaccounted for?

---
----
The above comments or recommendations are SWAG. Use at your own risk.
John, W9DDD

On 6/20/2021 12:27 AM, Robert Goff wrote:
> Many thanks to John (DDD) and Nick for the good info on the sync pulse
> magnet.  Whudda thunk it would be such an easy fix! And a special
> thanks to Nick again for the great resource of his website!
> 
> Having the sync pulse problem licked the next challenge has been the
> 177010 Selector Magnet Driver installed in the LESU of this 28ASR.  It
> seems like it is stuck in the marking position all the time, leading
> me to believe it either a) is broken or b) is blinded.
> 
> The manual for the selector magnet driver gives instructions for
> blinding both when the signals need to be monitored and when they
> don't.
> 
> The example for the first instance is : "the stunt box of a Page
> Printer (which would be receiving the line signals through its own
> selector) could be arranged so that its contacts would blind the
> Driver of a Reperforator at the receipt of a certain character
> sequence, and would unblind it at the receipt of another sequence."
> ---that part I understand. In this case a jumper in the PS is removed
> and the terminals run out to relay contacts on the stunt box.
> 
> With unmonitored signals the PS is simply jumpered to put the
> transistor in a steady marking state.
> 
> Question is: why would a person ever want to do this? There doesn't
> seem to be any way to switch in and out of blinding. Is there a way to
> see if a selector has been blinded without pulling the whole LESU out
> of the cabinet?
> Anybody run into this?
> Robert
> W7MKA
> ______________________________________________________________
> 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 w9ddd at tapr.org
>