Rock-Mite

The Rock-Mite arrived last week and I eagerly opened up the package and as soon as I could began work on the kit.

I followed the very useful instructions written by NE1RD as well as Dave Benson’s and after neatly placing out all parts, I checked them over to make sure everything was there.

NE1RD’s notes do have a few minor errors, there one large one re the check list (a mix up on Capacitors), but it is quite obvious and after checking the web I noted that other builders had also warned about this.

So with all parts accounted for I set to work and had the circuit board built by Saturday evening. Sunday morning I did a thorough check of my soldering to make sure there were no dry joints, I had also ordered the controls so by Sunday midday I was wired up and ready for the smoke test.

 Things then started to rapidly go downhill, connecting the circuit board to an antenna and applying power via a 9v battery I listened out for signals, nothing, it was dead. I replaced the headphones, (just in case) and tried again, nothing, not a whisper.

So I checked I was getting power in to the board it was quite low, 4v, I checked the battery and got 6volts, not a lot of power, so I looked around to see what I had available. I found my small adjustable DC power unit and set it to 12 volts and re-applied the power.

This time I got a puff of smoke by R6 and C103, C7, so I quickly switched off. Was it a small amount of flux burning or was it a problem? I persevered and re read the instructions, checking the wiring etc.

Resetting the power to 9v I fired up again, no smoke this time but still dead, not a sound. So the conclusion is I’ve either mounted a wrong part somewhere or there is dry joint/join or the worst case a part is damaged.

Power is definitely there and I have thoroughly checked for bad connections/dry joints, so at some stage I will have to a check of each part to make sure it is in the correct place and providing the correct resistance and voltage.

Interestingly on the Yahoo Rock-Mite support group there is a ham with a similar problem M6CLL, only he was getting signals off 9v but moved on to his PSU and something smoked. I may well contact him to compare notes. The investigations will continue and I will update as I go along, wish me luck…

……..Ah the joys of home building!

The completed Rock-Mite but sadly not working!