Here's examples of the 3 different switch LED brightness's. left light: right is brighter, middle light: left is brighter, right light: even. Out of 10 Q8's, 2 had uneven brightness. The center light below is the one from feralcomprehension which had the infamous "flicker/then out" problem. Note it's a little less bright than the others, that's because I swapped the resistor to a 16.9K from the stock 15K. After many hours on this, replaced the resistor, touched the iron to the LED pads to re-melt the solder - this works may times to fix poor solder connections. After that, the problem just took longer to happen, but was still there. DEL recommended to pull all the parts off the board,clean them up, and take a look. He noticed a couple of potential issues, but at that point, I already reflowed all the parts back on the board, re-assembled, and was testing. So far now, it's 6 1/2 hours without a flicker. If it survives the night, I'd assume it's good:
Here's a couple more. The original prototype (baked one) had only one LED, so clearly looks unbalanced in room light, looks much better actually in the dark. The one on the right uses the stock 15K resistor with a blue on the left, pink on the right. The pink doesn't show well in the pic for some reason:
Close-up of the blue/pink one. It's not as bright,still using the 15K stock resistor, but I prefer it at this level anyway:
So what does this mean for the flickering/failing problem of the switch LEDs? Well, it seems fixable with no new parts, but sure helps having a hot air rework station, and some soldering skills with the required tools. Also just because this one was fixable this way, doesn't necessarily they all can be fixed the same way, but chances are good I would think. There probably was some fault in the PCB board and/or combined with the production process that resulted in some failure rate, maybe 1%, maybe higher. Having 10 Q8's that worked is actually 2% of the first 500 piece batch.
Here's the view in front of me while typing this post:
Ok, that's totally useless but seemed relative at the moment. Flashlights everywhere...