ProffieBoard v2.2 - distorted sound

Hello forum!

I’m sorry that my first post here will be looking for help, but it was recommended to me in a reddit post.

I just got a TxqSaber ProffieBoard lightsaber today. To my surprise, the sound is terrible. I have browsed many forum threads, 99% of those claim that in such case, the problem is battery level. However, it’s been charging for several hours now and nothing changed. Multimeter shows 4.18V on the battery (under load) so in my opinion it’s charged enough, considering 18650 has a nominal voltage of 3.7V. From what I can see, wiring seems to be intact, no visible damages to the wires connecting the speaker.

Here’s a video:

What I was able to determine through some troubleshooting:

  • get_volume in Serial Monitor is 1200
  • beep sounds decent, compared to lightsaber sounds
  • resistance on speaker is about 8 ohm
  • the voltage between 5V and GND when lightsaber is on is about 2.25V. I think it might be a result of a faulty amplifier but I’m not sure since I’m an amateur when it comes to electronics. Also, serial monitor shows “Amplifier off”, I don’t know if that’s relevant.

Thank you in advance for any help. I wonder if there’s anything I can do to try to fix that at home, or is sending it back all the way to China the only way :frowning:

Generally, the amplifier will be turned on automatically when sound is played, although it doesn’t actually say anything when that happens.

This is the problem. When sound is playing, this is supposed to be 5 volts.
That basically means that the voltage booster on your board is not working.
I suggest checking with the seller if they can fix/repair/replace this for you.

Fixing it yourself is doable, but requires replacing surface-mounted components on the board.

Thank you so much for such a quick reply!

That’s what I was worrying would be the problem :frowning: I think that fixing/replacing this issue by the seller is possible, but since it’s a birthday gift for someone, I was hoping it would be possible to fix on spot. Can you tell me if maybe there’s a rough tutorial I could follow to fix this issue? I’m not an expert in soldering but I’ve done that in the past a couple of times.

Basically, there are two components that are likely to be the problem: L1 and and U3.
You can find those on the schematic here: Proffieboard V2.2
And if you click on the BOM, it will tell you what components those are, with possible links where you could buy replacement parts. The replacement parts are only a few dollars.

Next, you would need a hot-air soldering station, you don’t need anything fancy, but don’t try to do it with a regular hot-air gun, that is going to make it much harder. You will also need some solder paste, tweezers and a magnifying class. Ideally the magnifying glass is on a stand or something so you can use it without holding it. Head-mounted magnifiers also work well.

Then set the hot-air solderin station to something like 360 degrees, heat up the component, lift it off. (do not apply force, as that may lift the traces and damage the board.) Add a super-tiny
amount of solder paste if needed, then put the new component in place and heat it up again until the solder paste melts and turns shiny. Just be careful, because you could melt things or blow components of the board if you use too much heat or too much airflow.

Inspect your work and check for shorts before plugging anything in. If it doesn’t work, try again.

Wow, thank you so much for such a thorough instruction, I really appreciate it. I’ll wait for the vendor to propose his solution and if it doesn’t appeal to me, I’ll follow your advice. Thank you so much again. I think we can close this thread now.

Since I didn’t see it mentioned, I thought I would add that a temporary fix that probably wouldn’t void warranty or anything would be to jumper the 5.5 volt pad to BATT+ pad. Maximum volume might suffer slightly, but generally speaking it should clean up the sound for now, and also prove where the problem lies.

Hey @NoSloppy, you mentioned the 5.5V pad, but I can’t see it on the schematic here, can you tell me which one you mean?

@NoSloppy I tried to short 5V with BATT+ and it seems to work for the time being! I wonder though if that’s “healthy” for the board in the long run

Sorry, I mistyped. 5V pad. 6th down right next to BATT+.
If the booster is already bad, I don’t think there’s any “danger” in supplementing the power that way.

Right, I forgot that you can just short them…
Thanks for pointing that out NoSloppy. :slight_smile:

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I’ll probably do just that as this seems to be the easiest solution. I’ll still wait for the vendor to see what he offers though. Thank you so much for all your help! I will definitely stay at this forum now :wink:

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