I just completed replacing all of the mechanical encoders (6) on my Orion 1 and
thought I'd share some info.
Only 1 was bad (had dead spots), but I had this bright idea that I would
replace them all so I wouldn't have to do it again anytime soon.
This did complicate things a bit, but did solve the problem I knew I had with
one, and made one other work much smoother.
KE5C made a series of photos detailing how to get to the encoder board and
replace an encoder
(http://www.w4ish.net/Manuals/pdf/Orion%20RIT%20Encoder%20Replacement.pdf).
This is a very good starting point. I've listed some details I had to deal with
replacing them all.
One additional thing I ran into: The VFO A and B encoder shafts pass through a
bearing. The knob screws had been tightened down so tightly, that a 'nick' was
left on the shafts; large enough to not allow it pass through the bearing. I
had to polish this down to get these encoders out.
Here are the details:
1. The BEST thing would be to order the connector and bare board from
Ten-Tec if they have these items available, and put new encodes on it.
2. Take great care in handling the board that has the gold contacts for
the ‘chicklet’ keys. I consider this a design weakness in the Orion. Not only
are such keys mushy, they are easy to damage. Tactile switches with hinged
buttons would have been so much better. While they work, it does complicate
handling this board when servicing. I used close knit cotton gloves when
handling it and made sure the room was as dust free as possible. Also made sure
to wash my hands before any handling of this board, before putting the gloves
on. It’s very easy to cause these things to bounce or not work at all. Oil on
the pads or dust on the rubber contact inside the switch will cause all kinds
of problems. The smaller section of rubber ‘switches’ will stay on the board
pretty easily, but not the section around the LCD opening. This board and the
chicklets were covered after the encoder board was removed.
3. Don’t waste time trying to preserve an old encoder; clip the pins
and if you have a Dremel or something similar, cut the mounting brackets on the
encoder, then remove the pins and clips from the board. Be careful pulling the
cut pins out because you can pull a pad off with the pin, especially on plated
through holes; make sure the solder is well melted. The pins going through the
ground plane are more apt to be a problem, the others will pretty well fall out
when the pad is heated.
4. I do not have a de-soldering station due to the fact that it would
be very expensive for the occasional use I would give it, so removing the old
encoders was very time consuming. A bulb type de-soldering iron worked fine for
the contacts that were not going through the ground plane, but didn’t do much
with those connections that were. Solder wick and a 100 watt gun did ok, but I
finally had to use the heat and tap method (melt the solder and tap the board
against something to splatter the solder out). The mounting clips required the
100 watt gun and gentle pulling on the encoder. Basically getting one side out
a little and then the other until it was free. 100 watts was required, but not
something you want to leave on the pad too long.
5. There is no wiggle room on this board. The tolerances for the
mounting holes are very close. The holes for the clips have to be as near to
solder free as possible to be able to get the new encoders on. I trimmed what I
couldn’t wick, suck or sling off with an Xacto knife. Even then, I had to push
a small, thin flat head screwdriver into the mounting holes to make them large
enough to press the encoder mounting clips into. Even after all of this, it
took some very firm pressure to push them in.
6. The new encoders have an indexing tab. This needs to be cut off
flush. I used a polishing wheel on a Dremel to make sure it was smooth. The
metal is soft, so it’s easily cut.
7. The encoder pins are very thin, and I expect, could be damage
easily, so be sure to line them up well with the corresponding holes and be
sure the holes are clean before pushing the encoders onto the board (when I
said firm pressure before, I meant really firm at times. Might be easy to break
a pin is it isn’t well placed.)
8. Once I had all of the encoders pressed onto the board, before I
soldered anything in place, I donned the cotton gloves and mounted the encoder
board into place (with the spacers) and tightened the nylon/plastic (not sure
which) ‘nuts’ that hold this board onto the panel switch board. Once I had
verified that all the encoders turned freely. I soldered one clip and a couple
of pins, so the encoder would stay in place. I removed the board and soldered
everything well. Again, the clips required the 100 watt gun (as well as any
pins that passed through the ground plane). Exercise caution in heating the
connection for too long with a 100 watt gun.
9. I clipped any excess from the leads and then used a flux removal pen
to clean up the flux. This isn’t absolutely necessary, but the less ‘sticky’
stuff on the board, the better. Then wiped the board off with a clean
lint-free cloth (gently).
Hope this is helpful,
Anthony, K4ZNO (ex NT4X)
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