BetaFPV Lite FC V1.0 w/ Busted Gyro?

Hey all, fairly inexperienced so please bare with me. I’ve got an early lite board (flashed with NFE Silverware) that’s recently been acting up. Shortly after arming, the motors will spin up to what seems higher than normal and then cut completely, and the board will begin flashing its LEDs like it has low voltage. The flashing is sporadic however; it’ll flash for a moment, return solid, and go back to flashing. I get no throttle while the LEDs are flashing, but sometimes the board will spin up the motors again when they return solid. This generally lasts a second or two until the LEDs return to flashing. Interestingly, if I turn the quad upside-down, while armed, sometimes the motors will power on.

All of the components on the board look fine with no obvious marking. Ran fine until recently. I’ve tried the FC on a different frame, with different motors, but the issue persisted. The batteries don’t seem to be the culprit either as they work fine on an Inductrix board I have.

Looking for a final sanity check from the experts before I trash the board.

Hi buddy, welcome. Ok, that sounds like it is first finding bind with the tx, LEDs go solid, then you throttle up, something cuts out and then it flashes looking for autobind, finds tx again and then you’re armed again?

Couple of things it could be, but I’d first look at the crystal, if it’s the V1.0 board it’ll be the cylindrical component in the top. Most of the time the legs can sheer off half way up and will hold position up until you throttle up, the vibrations will break the connection, FC will failsafe sending the last TX packet, which in this case will likely be the throttle, and this will hold for a few seconds (that’s why it seems likes it rising) and then cuts out. Take some fine nose tweezers and carefully check if the legs are still intact. It may look fine but those old school crystal cylinders are one of the main culprits when you lose bind

Appreciate the response yets. Took a look at the crystal and everything appears fine on the outside. I was going to try to get some video of the board acting up, but now it just flashes like it’s receiving low battery voltage immediately after binding. I might comment out the low voltage check and see what it does, but I’m not sure how much time I want to commit to the project. Thanks again!

Maybe it is short circuit somewhere?

Post a video and will have a look

Have you replaced the battery lead? I have removed the pins and noticed they looked kind of black.

I once had a problem where 1 motor would not spin, yet if I plugged it in another connector it would work. And if I moved it back it would spin for a couple of seconds. I turned the quad upside down and did the gyro cal–right stick down 3 times. Oddly enough that solved the problem. You can always keep the pcb to use the mosfets in case you blow one.

You manage to replace mosfets? I have one board where I need to put new mosfets, but they are so tiny and no way I can desolder and solder them with any soldering iron I have… :frowning:

Hello SilverAG I use Hakko T11-B Tip for FX-901. The FX-901 runs on 4 AAs. I use rechargeable nicads. The iron does not come with the T-11B tip. It heats up in a jiffy around 40 seconds of so. For the BetaFPV brushed V1 I used IRLML6244TRPBF - Power MOSFET, N Channel, 20 V, 6.3 A, 0.021 ohm, SOT-23, Surface Mount. Newark Part number 84R9705. Looks like they are on sale for a little over 5 cents.

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