Friday, December 11, 2009

Preparing to build the SoftRock

I spent a couple of hours yesterday evening preparing to build the SoftRock 6.2 Lite kit that I hope to use as a panadapter for my K3. I started by printing out all the detailed build notes at WB5RVZ's SoftRock page. This describes building the receiver in seven separate stages, starting with the power supply and ending with the external connections. Each stage has its own bill of materials or components list, so I then checked the supplied components and put them into individual small polythene bags, one for each stage.

When I got to the local oscillator stage I realized that I didn't have a crystal. An email to the Elecraft reflector produced the information that the crystal used for the K3 panadapter version is a 32.768MHz. Even better, it produced an offer from Alan G4LWA to send me one he had that was surplus to requirements. Aren't hams a great bunch?

I'm also missing an unusual component, a 4.7uF ceramic capacitor listed in the operational amplifiers stage as Cxx with the note "for audio test". I can't see where on the board that goes and on a scan through the instructions I couldn't see any mention of it. I'm sure I have a 4.7uF electrolytic capacitor in my parts box which will hopefully do, but I think I'll have to solve this problem when I come to it.

I'm a bit apprehensive at building this kit. I'm going to take it very slowly, in stages, no more than one every few days, not least because I can easily set off my back problems by spending too long hunched over the desk which is necessary to see what I am doing using my magnifier headset.

There are about 4 SMT ICs to be soldered in, and ten SMT capacitors. At the moment, the capacitors look more scary than the ICs. I can't even see how to get them off the backing strip without them pinging off to be lost forever in the carpet. At least the ICs are big enough to hold on to.

Although building the receiver in stages makes a lot of sense, I'm wondering if it would be easier to solder all the SMT parts on first. I think it would be easier to do while I can put the board flat on the bench. As soon as any through-hole parts are on there they will restrict access and make it harder to keep the board in a stable position. I need to think about what is the best way to proceed before I can actually start.
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