[GreenKeys] New to me Model 28 and needing assistance

[Mike]

I like that your 28 has the Teletype globe badge. Very niceMike
-------- Original message --------From: SK Campbell <campbellsk at comcast.net> Date: 1/1/22  5:58 PM  (GMT-07:00) To: GreenKeys at mailman.qth.net Subject: Re: [GreenKeys] New to me Model 28 and needing assistance Happy New Year everyone! I have been a GreenKeys subscriber for some time and really enjoy readingthe messages daily. Always great and informative!This is my follow-up and update message from October when I startedrestoring a handsome Model 28 KSR unit. First things first, a big thank youto the many GreenKeys members helping me with my questions and concerns withthis special machine: especially Nick England (K4NYM), Jim Cooper (W2JC),John Koster (W9DDD), and Jerry Murphy.A very special thank you to Paul Cembura (Mr. RTTY) for his parts,suggestions and real-world operations with Teletypes from the past. Always apleasure talking with him. I have the unit working with my HAL-5000 and copying ITTY with no errors;the next step will be interfacing it with my vintage Collins S-line setupand/or my ICOM 7100 (set-up as a desktop). Any suggestions with thoseseparate arrangements, please feel free sharing with your suggestions. Theonly issue I need to fix is the signal bell, which someone disconnectedincluding removal of the stunt box switch, wiring and upper case "S"function bar (Mr. RTTY is working on those part requests for me).I am now in the market for a standalone LDX (60 wpm) and Reperforator (60wpm) and will gladly pay costs and shipping. Mr. RTTY has my request, aswell.Here is a short video of the Model 28 copying ITTY and sounding like a happy1970's machine:https://youtu.be/osJZDypBMfUThank you all for the helpful and continued information. I am so glad thereis a great resource for this vintage historical equipment.73,W7SKCW7SKC1 at gmail.com <mailto:W7SKC1 at gmail.com> campbellsk at comcast.net <mailto:campbellsk at comcast.net> Steve		_____________________________________________		From: SK Campbell <campbellsk at comcast.net> 		Sent: Thursday, October 7, 2021 14:21		To: GreenKeys at mailman.qth.net		Subject: New to me Model 28 and needing assistance		I have been a GreenKeys subscriber for some time and this ismy first attempt generating a message seeking information and guidance fromthe experts. I have acquired a nice-looking Model 28 KSR from Wayne(WB4OGM). Thank you, Wayne!		With assistance of Nick England (K4NYW) and his Navy-Radiowebsite, we suspect the unit had a life with the Army, which was unusualsince they mainly used Kleinschmidt's. 		It has the following components:		.	Typing unit, MX-3311/UG, LP 77 YD AGM		.	Keying unit, LK 25ARN, Stunt box AEP (WD 3047?)		.	Cabinet, LAC 203		.	Motor unit, LMU 3. The motor intermediate and piniongears have part numbers for 60 wpm. (I have an extra set, verified via partnumbers for 107 wpm.)		.	LESU 42, WD3716 (Nick suggested that the TT-243/FGis similar, since I could not find the WD on the Navy-Radio site for theLESU 42, I did find a TM on eBay). Fortunately, or unfortunately, the unitappears to have been heavily modified for other service, because the LESUequipment does not match the original specifications. There are solid-statedevices underside of each LESU sections. (I have not tried reverseengineering the motor control, shunt and line relays or the DC sourcesections of the LESU, yet.)		I have made a cautionary power up with the unit and the"Maintenance Light" works as advertised, however, no joy with the motor ortyping unit with the "Normal On" and main power switches on. After someserious wire tracing, resistance and voltage checks, I believe the unitcould fire up. I have tested the motor and it does run. And I cleaned thecontacts on Ji/P1 and J2/P2.		The signal path from TB 1 (back of cabinet terminals 5 and15) route through the signal network on the bottom of the cabinet to two RCAjacks (labeled "keyboard" and "printer"). The motor control component on theLESU has one lead to the same location on the bottom with its own RCA jacklabeled "motor". I believe this is the main motor control lead for the startrelay, etc. With caution, I added a 100-ohm resistor to the tip and sleeveof the "Motor" RCA connections and the motor starts and runs without anyapparent issues. The unit appears having a satisfactory current loop (notrunning open) and the red keys are operational, however, the green keys arenot responding. (The keyboard is mechanically unlocked with the red key"UNLK"). The code bar and transfer levels indicate the correct alphanumerickey when pressed.		I have measured approximately 143vdc on numerous terminalsof the main TB1 (back of cabinet), I suspect for the local loop voltage. 		Resistances to ground (RCA jacks):		"Keyboard" = open		"Printer" = 55 ohms		"Motor" = open		Voltages to ground (RCA jacks) Normal power ON:		"Keyboard" = 2.6 vdc		"Printer" = 3.3 vdc		"Motor" = 7.0 vdc		My expectation is to use an acquired HAL 5000 as ademodulator and interface the Mod 28 and one of my vintage radios. Again,before I heavily modify this unit back to semi-stock operation for amateurradio use, I wanted to ensure it is mechanically sound and functionallyoperational.		Since I do not want to damage any components, I am seekingany and all guidance and information on moving forward with least amount ofconsternation, on possible interface connections, testing andtroubleshooting. Was this unit used with a PC and software, e.g., MTTY orsimilar? I do not know.		My experience is limited; however, I have worked with aKleinschmidt and built a TU for it back in the 70's and always wanted to getback into RTTY. During my telecommunications career, I was assigned to thetoll test board department and TOC (I really enjoyed that work), where weused Model 28s for monitoring and testing of local loops for the USAF, NWS,and law enforcement; any TTY mechanical issues went to the localprivate-line repairman. Recently, I have watched numerous RTTY YouTubevideos (Marc and Ethan) and have gained a greater understanding andextremely thankful that GreenKeys is so active and a positive resource!		Thank you all, in advance.		Steve W7SKC		W7SKC1 at gmail.com <mailto:W7SKC1 at gmail.com> 		campbellsk at comcast.net <mailto:campbellsk at comcast.net> ______________________________________________________________GreenKeys mailing listHome: http://mailman.qth.net/mailman/listinfo/greenkeysHelp: http://mailman.qth.net/mmfaq.htmPost: 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.htmlThis list hosted by: http://www.qsl.netPlease help support this email list: http://www.qsl.net/donate.htmlMessage delivered to mmcauley at cox.net
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