Mastering Surface Mount Technology

The MIC3289 is an interesting chip. Using a Saleae Logic Probe I have looked at the one wire pulses sent to the Digital Control pin (DC).

There is an error in the version 1.0 software. You can store any intensity value between 0 and 15 into the PIC eeprom. When the PIC code starts, it retrieves this value and sends out brightness presetting pulses before the LEDs are turned on, so that any brightness value will be first used.

But, when storing intensity value 15, there should be no presetting brightness pulses. And yet there is 1, just like when storing intensity value 14. The code does not handle the value 15 correctly. Does this matter. Not really. I just thought it odd that there was such a fundamental coding error.

Bought this back in 2014. Just finished building all 3 kits, since I finally bought a hot air station, fine tip soldering iron, really nice tweezers. Used Maker Paste Low Temp Solder. Learned a lot.

LED tester: did one side, chip by chip, everything very neat. But when I did the underside, held hot air on too long and desoldered some components on the other side. Got everything back on but stuff was crooked.

PWM controller. Again, did one component at a time using Maker Paste and hot air. Had some trouble with a cap and resistor next to each other. This stuff is small! Had the most trouble with the electrolytic as their leads do not show much when mounted for soldering. Had to trim some metal off of the pot as it would have shorted something on board.

Ring Light. Again did one component at a time. The U1 chip managed to bounce off my bench. That took about 20 minutes to find it. But soldered it on first. Then caps and resistors, building out away from components already soldered. This went much smoother. LEDs were easy, one at a time, as I finally learned to hold the hot air nozzle farther away from board.

Everything works. Have Ring Light on with max brightness for last hour, draws about 350 mA at 5.0 volts. U1 and L1 get pretty hot.

Made me (almost) want to build the Lab Stiks but I don`t have parts and probably will not spend time to track ICs down as they are probably too old and obsolete.

Thanks to Elektor and Vincent for these kits. Difficult but worth it.