Colin's Astronomy Pages

Power box
Scope Power Distribution Box

Contents

As this is quite a large project, I've decided to split this project into several pages. Each page dealing with a different aspect of the project.

Overview

This box is attached to the scope, it is used to as a connection point for the power box, and the electrical elements on the scope.

Design

Whilst in my local Maplin store, I decided to pick up an Ice Blue plastic Enclosure, outer dimensions are 100x50x21(mm). It's semi transparent, so you'd better be good a soldering and wiring - it's on display!

A quick look at the box will show that it's got groves in the side walls, which are just the right width to slot in a PCB, however, it means that the PCB needs to be less than 21mm wide! So that it can fit into the box. For my purposes this is ideal.

The plan is to place two PCB's into the box, one to provide power to heater elements, and the other, will provide power to the scope and also to the lighting circuit.

Finally, in middle of the box, I will place a standard 8 Pin Din socket. This will be where the cable that travels to the power box will plug in.

PCB creation

For this part of the project, you'll need two small PCB's. I used a single sided PCB, to create both boards at the same time. Then seperated the boards with a hacksaw. This part of the project wastes alots of PCB. As there isn't a standard size PCB available.
The two PCB's are 10cm long, and 20mm wide.

To use this image, print the board layout into transparency, the use the photo-etching techinque to produce the two boards. Once etched, you should then seperated the two boards.

The top board is used to distrubute power to the heater elements. To complete this, you'll need to solder 6 PCB mount 3.5mm Mono jack sockets onto the board.

The bottom board has one mono jack socket, this is for the lighting loom. the other pair of pads and tracks are for the main telescope power. You might want to omit these from your box.

The pads are will be used to connect to the DIN socket. The order for connection is entirely up to you, but it's important that you know which circuit is which. The last thing you want to do is damage your expensive scope, with incorrect wiring. (I've got a test box, that lights an LED when the connected to the scopes power supply.)

Box Modification

Next you'll need to modify the box, by cutting out the holes needed for the jack sockets, DIN socket and wire that connects to the scope.

I placed the PCB's into the box and pressed them hard into the two outer most slots. Then I marked where the holes needed to be for the jack sockets. And drilled them out using a bench drill. Take your time with this, and make sure that you're accurate, as it will ruin the box if you make a mistake.

Next I drilled the large hole for the DIN socket. As there's a plate in front of the socket, accuract isn't as vital here. It's important that the hole remains covered by the plate though. Also drill the big hole first, then the two smaller screw holes, that wat the socket will act as a template and mark the holes for you

Once you've completed drilling all the holes, you'll need to knock off the top corners of the PCB, so that it will fix firmly against the box lid. Then attach the sockets through the holes and tighen up the nuts on the sockets. This will hold the PCB's in position.

Add the wires that connect the PCB's to the socket, and solder everything together. Also don't forget to make the lead that attaches to the scope. You'll also need a hold in the box to allow that lead to escape. This is part of a power lead, so uses a DC 2.5mm jack plug at the free end. Make sure that you cut this cable long enough so that it will run from the place you intend putting the box, into the DC jack on the LX90.

Finally, use sticky backed velco to attach the box to the scope.

Power box Scope Power Distribution Box

Power box
Scope Power Distribution Box