November 28, 2022


Best Technology Perfection

Epoxy Blob Excised Out Of Broken Multimeter, Replaced With A QFP

The black blobs on low-priced PCBs haunt those of us with a practice of having points apart when they fall short. There is no aspect selection to glimpse up, no pinout to probe, and if magic smoke is released from the epoxy-buried silicon, the entire PCB is toast. That is why it matters that [Throbscottle] shared his journey of restoring a vintage multimeter whose epoxy-covered one-chip-multimeter ICL7106 heart developed an interior reference fault. When a multimeter’s inner voltage reference goes, the meter by natural means will become worthless. More affordable multimeters, we bin, but this one arguably was well worth reviving.

[Throbscottle] does not just demonstrate what he completed, he also demonstrates precisely how he went by way of the approach, in a way that we can master to repeat it if at any time needed. Guidelines on eliminating the epoxy coating, isolating IC pins from shorting to recently uncovered tracks, matching pinouts in between the COB (Chip On Board, the epoxy-lined silicon) and the QFP offers, carefully attaching wires to the board from the QFP’s legs, then examining the connections – he went out of his way to make the trick of this fix accessible to us. The Instructables UI does not make it evident, but there’s a big range of high-good quality photos for each and every phase, way too.

The multimeter actions when once again and is back again in [Throbscottle]’s arsenal. He’s acquired a prolific background of sharing his techniques with hackers – as far back again as 2011, we have coated his guide on reverse-engineering PCBs, a skillset that no question produced this repair service feasible. This hack, in convert proves to us that, even when facing the void of an epoxy blob, we have a shot at repairing the thing. If you ponder why these black blobs plague all the low cost units, here’s an intro.

We thank [electronoob] for sharing this with us!