PCB testing troubles

[Grantus]

Hi, Brach

Geez, sorry I need so much handholding. The 120 ohm R15 resistor does not glow or spark when the tube is removed. Just to be clear, it starts glowing first, then began to spark, like a small fireworks sparkler. It’s quite … sparky.

I also took a look at the solder side of the board, and there doesn’t seem to be any connections from R15 to nearby soldering points.

Thanks again

Grant

[brach]

It’s no problem. I like helping people get their products working right.
Here’s another edited photo that you sent me earlier…just to illustrate these points…

If it’s sparking, the sparks have to be going somewhere…usually a black spot on the board. Can you find out where they are going? It would helpful if you could try to take a couple more close up pics of R15, both sides of the board. Maybe i could see something.
The via isn’t a soldering point, just a tiny hole through the pcb with no blue solder mask on top of it, so they are easy to accidentally bridge solder to if it overhangs the pad much.
-Brach

[Grantus]

Hi Brach

I’ll send you some pictures by email. The sparks were generally going straight up from the resistor, so I don’t see much of a black spot on the board.

Thanks

Grant

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