[Top] [All Lists]

Re: [TowerTalk] HDR-300 wiring

To: Rick Craig <>, TowerTalk <>
Subject: Re: [TowerTalk] HDR-300 wiring
Date: Sun, 27 Dec 2009 21:00:22 +0000 (UTC)
List-post: <">>


Your observations are helpful.  I did reverse these two pins 9 and 10 and now 
have readings but they are way off, ranging from 328 to 870!  Yes, 870.  That 
indicates the shaft traveled some 540 degrees, verified by eyeball.  It would 
have been more had I not stopped short of using up all the slack in the loops.  
So, it seems that the limit switch in at least one direction did not stop the 
motor before it went too far.  Now, when I try to reverse direction, I cannot 
get very far before the other limit switch actuates, stopping rotation.  
Probably going back thru a switch and then hitting the otherI had inspected the 
gears on the limit switch actuator and found good gear engagement, nothing 
looking funny.  I did not check the setscrew on the gear but doubt it is loose. 

Given this, has anyone seen the rotor 'coast' by the limit switches and how 
does one prevent it or adjust it, if there is an adjustment.  Yeah, I know I 
can always ensure I stop short of the limit.  I assume I will need to somehow 
reset the physical calibration of the pot to the limit switch actuator 
position.  The manual does not give the resistance readings for full CCW or 
full CW.  It simpl y states the range of readings making me guess.  Also, my 
control board is the original.  Not the one that allows a North centered or 
South centered option.  The manual is not very specific and led me to believe I 
need to see 180 degrees with the rotation in the halfway position. 

----- Original Message ----- 
From: "Rick Craig" <rick. craig> 
To: " al n6ta" < al> 
Sent: Sunday, December 27, 2009 8:09:14 AM GMT -08:00 US/Canada Pacific 
Subject: Re: HDR-300 wiring 

Hi Al, it looks like you have two wires swapped going to the pot.  Pin 10 
should ground one side of the pot, pin 9 is the wiper of the pot, and pin 8 
will normally have 5 VDC on it.  Your measurements show pin 10 to be the wiper 
and pin 9 is probably the grounded side of the pot.  So you need to reverse the 
wires going to Pins 9 and 10. 

Good luck, Rick, N6ND 

Well, I replaced the T2X with an old HDR-300 (S/N 40) and it turns the 4 el 
Stepp I r fine.  But, the digital readout is hosed.  As currently wired, I get 
no numbers, only three dashes.  I climbed to the rotor, pulled the housing off 
and confirmed the wiring of the potentiometer.  The resistance measurements at 
full CCW , half way and full CW are: Pin 8-9: always 1000 Ohms regardless of 
position Pins 8-10: CCW : 520, half: 344, CW: 141  Total range is ~380 Pins 
9-10: CCW : 480, half: 656, CW: 861  Total range is ~380 The totals always add 
to 1000 as expected and the range is about 380 Ohms, near the specified 400 
Ohms for the expected travel and overage. What bugs me is that the manual says: 
8-10: 1000 9-10: 150-550 8-9:   450-850 I have checked three different 
revisions of the manual: the oldest that I have, a newer 300 rev and the 300A 
rev.  The details are the same in terms of the definitions of what pin goes to 
what physical terminal on the pot and the Cinch connector. I pulled the lid on 
the control box and checked the connector to PCB wiring and it is correct. Any 
suggestions or readings from your rotor would be welcomed. Like I said, the 
beam will turn and that is an improvement! 73, Al 

n6nd at arrl dot net

TowerTalk mailing list
<Prev in Thread] Current Thread [Next in Thread>