On Sunday, April 05, 1998 4:06 PM, Wayne Karlin wrote:

> After reading some of the messages on "Overheat" it came to mine.
> Usually I have no problem with the 416 cooling, living at 56deg. lat. in
> northern British Columbia, but recently with the weather warming I`ve
> noticed a rise in the head temp. display as I shoot more images, which
> has added extra noise to the images. When I first started using the 416
> I had a problem with the cable disconnecting when I slewed the scope, so
> what I`ve done was to wrap 2in. duckt tape around from the color wheel
> across the camera fins around the back of the camera holding down the
> cable across the other side of the fins and back to the other side of
> the color wheel, which works well for securing the cable to the camera
> but probably is reducing the head cooling. I would appreciate any better
> ideas for securing the cable to the camera head properly. Thanks, Wayne
> Karlin / BUTLER RIDGE OBSERVATORY
>

I believe the following text posted quite some time ago will
provide a simple, but effective solution for unwanted head cable
disconnects and inadequate air . I will forward a small GIF file to
Ed Stewart along with this text for consideration on his fine MAPUG
Topical Archives: http://www.austin.cc.tx.us/astro-ES/AstroDesigns/

The GIF shows the relative locations for the head cable clips.
The illustration also shows the location of a small 1-9/16" cooling
fan. Both have been in use over 3 years. The small fan prevents
overheating during low air flows such as indoor testing. I cover
proper selection and use of supplementary cooling under the subject:
Supplementary Fan Cooling of the Pictor 416/1616.

Early Pictor 416/1616 CCD cameras made no reference to
avoiding head cable disconnection while the control box is
powered up. Later, Meade felt the camera's electronics
could be damaged if the head cable was removed while
powered up and so advised in subsequent user manuals.
I allowed cable removal to avoid pulling the control box
and possibly my laptop during a slew.

Since Meade now advises against head cable removal,
I added cable clamps which allow no tools cable attachment,
even during sub-zero weather. In spite of many head
disconnects without any problems, I decided to add the clips
to assure that the head cable could not disconnect.


----------------------------------------------------------------------------------------
Hardware store parts needed:

(2) #3304S Serva-Lite 1/4" X 3/4" wide nylon cable clamps
(2) 3-48 X 1/4" stainless machine screw
(2) 3-48 stainless machine screw nuts
(2) #2 stainless flat washers

3/32" drill bit
Locktite medium strength thread locking compound.
-----------------------------------------------------------------------------------------

Similar clamps made out of polyethylene or polypropylene are
not suitable. If the clamp doesn't spring back, it's not nylon.

I used stainless steel screws, but brass or steel are fine.

Mark the locations for the cable clips as shown in the attached
picture. You may want to drill more to the outside of the camera
to avoid drilling into the sealed camera case. Use a 3/32" drill
to make your holes. Next, drill the nylon cable clamps just inside
the molded mounting hole. I slightly enlarged the cable clamp
with an Exacto knife and a #11 surgical blade (standard Exacto
blade) to enable insertion of a screwdriver for tightening.

Install the #2 washer onto the screw and into the cable clamp.
Insert the assembly through the clamp. Add Locktite to the threads.
Next, turn the camera over and slide the nut into the cooling fin.
Using a jewelers screwdriver or similar object, start the nut on the
screw. You may want to slightly pull the screw out to enable
starting the nut. Use the jewelers screwdriver to jam the nut
while using another small jewelers screwdriver to tighten the
screw.

To install the head cable, simply spread the clips with your
fingers and insert the cable. Next, plug the cable into the
Pictor camera. Reverse this procedure to remove the head cable.


--
Michael Hart
Husen Observatory

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