Author Topic: Car Beeper water damage question (Read 1192 times)

ImpulsiveJames · « **on:** May 07, 2022, 02:31:57 am »

Sooo.... we went rafting and.....had a little accident....

Water got in our car unlock beeper and stopped working. I know very little about RF/transmitting. I actually just picked up my first Oscilloscope last week and am just getting acquainted.

So far I've used the oscilloscope to trace the signal from the main controller chip to the N2t transistor, then it looks like it goes through the cap to the L3 (inductor?), then the antenna. I guess I'm having some issues testing these inductors, they don't seem to be passing any current/can't measure any ohms. The Cap also doesn't make sense to me, won't the cap smooth out the data signal over the air?

inse · « **Reply #1 on:** May 07, 2022, 07:03:01 am »

I suppose to clean the PCB with alcohol and a toothbrush to remove the flux and allow better inspection.
Did you build this yourself?
It looks like hand soldered and 3D printed

Jeff eelcr · « **Reply #2 on:** May 07, 2022, 09:02:39 am »

Inductors that do not read resistance are open.
As to value you need a 2nd working unit for comparison.
Jeff

ImpulsiveJames · « **Reply #3 on:** May 07, 2022, 07:18:31 pm »

Quote from: inse on May 07, 2022, 07:03:01 am

I suppose to clean the PCB with alcohol and a toothbrush to remove the flux and allow better inspection.
Did you build this yourself?
It looks like hand soldered and 3D printed

I did that before, but was poking around again soldering/desoldering and didn't clean it back up - my bad.

I just have it held with a 3d printed magnetic pcb holder

ImpulsiveJames · « **Reply #4 on:** May 07, 2022, 07:41:32 pm »

Once again, I'm just getting into this stuff and am still a total noob

I've been doing some more readings, and do have a second one that I've been testing with. I do see one major difference with the oscilloscope. These pictures are from Auto mode probing each side of the N2t transistor (NPN?)

Bad Unit Collector