Speaker Buzz

I was sent a hilt to repair. Owner thought it was a bad speaker. There’s a hum in it - see the video. This happens with or without a blade.

I’ve replaced the following:

  • speaker
  • SD card with files copied from original zip rather than the old SD
  • proffieboard

Still the same hum. I can only conclude it’s a wiring issue, but damned if i know what to look for. The wiring all appears to be PTFE. Speaker wires are twisted - the only thing I can think of is putting shielding around them. Which is to say, I’m kind of stumped. Thoughts?

Here’s the config: #ifdef CONFIG_TOP#include "proffieboard_v2_config.h"#define NUM_BLADES 1#d - Pastebin.com

That almost sounds like the sound you get if you use the broken ProffieOS 6.8 that I put on github for half a day before I fixed it. Are you using ProffieOS 6.8?

6.9. not sure what it was running prior but I’d guess 6.7 at the vet latest. Probably older.

Are you sure that’s not how the font(s) sound?
It’s hard to tell with fonts I don’t know.

Yup. I can send you the fonts but it’s absolutely not correct. I’m almost wondering if it’s the battery or something. That or a ground loop.

I think it would be easier to try it with the a super-simple config file and the default fonts instead of sending the fonts to me. This would rule out any programming or font issues.

Based on what I see though, the sound is super weird, and the buzz seems fairly strong. Minor wiring issues aren’t going to cause this, but maybe some major ones:

  1. a short between one of the two speaker wires and something else (like GND, batt+ or an LED pad.)
  2. A bad battery. (If the battery protection circuit is turning on-off many times per second, it could possibly create something like this?)
  3. A short between the 5V pad and something else.
  4. A short between batt+ and something else. (This one would be easy to notice though, because it would get hot!)

1 - nope
2 - nope - isolated with a known good battery
3 - nope - new board, soldered it myself
4 - maybe?

I’m gonna do a full rebuild. I hate the build in this thing anyway. Gonna do a chassis with a removable battery and a chassis PCB connection, not this wire’s nest that’s probably hiding a short.

son of a… it was the font. The fonts were all kinds of dodgy. I hooked it up to serial monitor after basically isolating every single thing from the hilt, and damned if it didn’t still do it. cycled through the presets (i’m really starting to love serial monitor for this) and come to find two of the fonts are a problem for the board to parse through. i loaded BLUE and GREEN on there and wouldn’t you know it.

Whatever, i’m doing a full rebuild anyway. This chassis sucks. Thanks prof. It never even occurred to me that the “good” copies of the fonts could be bad. I just assumed font creators, you know, test them.

1 Like

Some people like buzz.

Glad yo found it, FWIW @NoSloppy has a voice-saber font a lot of us use to isolate stuff. I can’t find the link right now though.

LMK if you find it, that sounds great. Just another experience added to my troubleshooting library. we learn by breaking things.