I’m kind of at a position where I don’t know what to do, and I’m having a feeling that I shouldn’t be working on machinery today (the temporary knack muse has left me). I got the power supply and local oscillator installed, but I’m now at an block: when I powered up my Softrock with a current limiting resistor in place, I see a current of about 3.5ma, which seems within reason. I then power it up without, and see a current of 22ma, which is not so good (it should be less than 4ma) and no hint that it is oscillating when I tune in my FT-817 anywhere near the 28.224 Mhz that the oscillator should be running at. I measure the following voltages:
- R11 hairpin: 4.92 volts, nominal, indicates that the voltage regulator is working.
- R15 hairpin: 3.94 volts, nominal value should be < R11, mine is significantly lower than the supply voltage, might indicate a problem.
- R12 hairpin: 2.37 volts, should < 2.5, seems nominal.
- R17 hairpin: 4.7 volts, should be > 2.5, mine seems high perhaps.
I’m going to ponder it, and read through the softrock40 Yahoo! group for help.
Here are some pictures in the meantime.
Addendum: It oscillates! I found that I had a solder bridge across the leads of C12. Now, I can hear it LOUDLY in my FT-817, although the oscillator doesn’t sound all that smooth. Still, all it has to do is drive those flip flops, so I doubt it matters. Current draw is 13.6ma, which seems a bit high, at least if you take the builder’s guide as true, but it has a fairly obvious mistake, so I am not sure that I should trust his 1.8ma as true either. Still, I’ll go back and remeasure the voltages going forward, and take a bit of a break before I go onto the next round of adding SMT caps and ICs.
Addendum2: Coil, coil, toil and trouble. Man, making 38T through one of these coils is tough, even with #30 wire. Photographing it with a digital camera does make it easier to double check your work.