[GreenKeys] MOD 28 TD LXD 38L AND LXD 31 (ON EBAY)

[Albert Last]

--------------------------------------------
On Wed, 2/7/18, Jerry Murphy <gfmurphy at earthlink.net> wrote:

 Subject: Re: [GreenKeys] MOD 28 TD LXD 38L AND LXD 31 (ON EBAY)
 To: Al.Last at sbcglobal.net
 Date: Wednesday, February 7, 2018, 9:07 AM
 

Hello Jerry,

Thanks for the response. I'm trying another email system now so I hope I am responding correctly!!
The unit I am referring to is Stamped on the mech as LXD 38 L. I just reconfurmed the stamped nominclature in the td. It is the "miniturized" small stand alone td and does work except that the "free  run" slide switch is broken off and is difficuult to use. Also, I removed the snall contact cover and found it appears that the normal resstosition of contat is in the SPACE position. I changed it to be in the mark position???? it does seem that it works but accordint to your email if it is low level then thee gold contaccts may not handle to 60 ms current and could burn them. Hummm

Al W6GSQ



 Hi Al:
 
 You say that you have an
 LXD38L.  LXD38 is a standard Teletype number while LXD38L
 is one that I'm not
 familiar with. 
 LXD38 is a 7.42 transmission pattern, low-level TD.  LXD31
 is a 7.00 transmission pattern, high-
 level  TD.  Low-level means the transmitting
 contacts are optimized for low voltage and low current while
 high
 level means that the transmitting
 contacts are optimized for 60ma and high loop voltages.  An
 LXD31 will fit
 and the gears will mesh but 
 the transmitted signal will not be correct.  You could
 remove the 7.42 transmitting
 cam from the
 LXD38 and put it in the LXD31 and everything would be OK. 
 Replacing the cam does not
 require doing any
 adjustments.  The information regarding LXD31 and LXD38
 comes from the Navy Teletype
 cross reference
 document:
           
 http://www.navy-radio.com/tty/navelex-tty-1977.pdf
 
 Is it possible that your
 LXD38L is actually an LXD28L?  28L is a common Bell System
 identification.  What kind
 of problem are
 you having with your existing TD?  Is it being used in an
 ASR or a stand-alone base?
 
 Regards, Jerry Murphy
 
   
 
 -----Original Message-----
 
 From: Al.Last at sbcglobal.net
 
 Sent: Jan 29, 2018 1:46 PM
 
 To: greenkeys at mailman.qth.net
 
 Subject: [GreenKeys] MOD 28 TD LXD 38L AND
 LXD 31 (ON EBAY)
 
 
 
  
  
 
 
 I have the lxd 38l head but its has some problems. Ii I
 see an LXD 31 
 listed and want to know if they are interchangeable. Any
 help would be 
 appreciated. I do have the manual from on line of the LXD
 maintenance Bulletin 
 235B dated 1968 (updated).
  
 Thanks, Al  W6GSQ