[TenTec] Ten Tec 301 Remote TU Knob

[John Hensley]

Here is some helpful information for those of you using the Ten Tec 301 RS232Remote knob or perhaps would run if it worked.  
The A and B encoder outputs can be looked at on a dual trace scope.  The squarewave trace of A to B is 90 degrees out of phase.  If it moves cleanly as yourotate the knob back & forth, the encoder is good.  Although they are not foolproof, the encoder is protected with diodes to prevent damage if the + and -power leads are reversed. 
Now check the wiring  (data courtesy of Dale, KG5U) :

		
	
	
		
			
				                                 Description


			
			
				Encoder                                                  DB-25


			
		
		
			
				Ground                                                    " - neg" pins 1 & 14

				Phase 1 ("A")                                          pin 6
Phase 2 ("B")                                          pin 8
+5v                                                           pin 16

			
			
				

(Shielded control cable should be used for long lengths and a snap on
Toroid suppressor wouldn't hurt around other computer gear or transceivers).

The best news comes from Bill Cotter who kindly provided me with this:
If you need another encoder:

Original encoder: OAK-GRIGSBY 90Q125-02-00245

Substitutes: Bourns ENA1J-B28-L00128 (same bottom connects as Grigsby)or Bourns ENS1J-B28-R00128 (side connect version)
I found the Bourns encoder at Allied Electric for about $34, quantity of one.  Thatis a great price.
The data sheets for both the original and the Bourns are temporarily available onmy website:
http://www.w5jv.com/Ten_Tec/301_RS232_Encoder/
Cheers,
John W5JV


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