ETX TECHNICAL TIPS
From: email@example.com Greetings from over the pond from the U.K.! You will be pleased to know that your site was a major influence of my recently purchased ETX90EC. I would like to clarify the set up for both the external power supply, and the P.C. serial cable, from a UK perspective. There is obviously lots of advice from the U.S., but alas the part numbers and store details do not apply over here. As an electronics engineer, I decided to investigate and pass on my findings. One common fault in using a serial cable taken from a telephone handset is that the release tab on the connector is cut off. This means that once it is inserted in the Autostar, it is almost impossible to get it out!!! NOTE: The usual disclaimers apply here! Power Supply =========== I currently use a UNIROSS PSU, fully regulated, and rated at 12V and 1A. This is more than enough for the MEADE ETX90, and is readily available here in the UK for around 12 (Part number VN10, see MAPLIN, below). Be sure to configure it for 12V, and use the 2.5mm connector, (the RED tipped connector). ENSURE THAT THE TIP IS CONFIGURED FOR POSITIVE (else expect some smoke!) Serial Cable ============ The connector that fits into the Autostar is known as a 4C4P (4 connectors in a body designed for 6). The 8C8P is commonly known as an RJ45, used in computer LAN connections for example. I have seen some postings that use an RJ11, with the edges filed down, which seems to work. This is because it is a 4C6P connector, i.e. it uses 4 individual connectors, in the width of a connector designed for 6! That explains why it is too wide. To cut this short, this is what you need here in the U.K. :- 1 x 4C4P connector part No. JW42 (about 0.39), 10 x metres of XR86 (0.41 per metre flat cable), 1 x RK61 (9way D connector), 1 x FP27 (Hood). The above part numbers refer to MAPLIN, (www.maplin.co.uk), the biggest consumer electronics supplier here in the U.K. Manufacture the cable as per the other postings at Mike's ETX site, but the 4C4P connector is a little fiddly. Cut back precisely 4mm of outer insulation from the flat cable. Insert this into the 4C4P connector, MAKING SURE NO WIRES ARE BENT OVER. Don't worry, it will go in first time! If you do not have a crimping tool to hand, GENTLY push the 4 gold contacts into the connector with long nosed pliers, one at a time, until they are tight. Also, using a small screwdriver, push on the small rectangle which sits over the main cable - this indents the plastic of the cover into the cable, and forms a primitive strain relief. If you do have a crimping tool, this is done in one fell swoop. Incidentally, the crimping tool from MAPLIN is around 6.00. Once you have soldered the 9 way connector to the other end of the cable, check the cable using a multimeter or simple lamp & battery. This took me around 5 minutes to make, and worked first time. And that's it ! one P.C. to Autostar cable for around 5.00! Keep up the good work, and now lets go outside and see if I can actually SEE anything with it!! Steve Jarman - Bexleyheath, Kent, England mailto:firstname.lastname@example.org
Return to the top of this page.
Go back to the Tech Tips page.
Go back to the ETX Home Page.