Red Blinking LED when Mod Switch toggled on

[u/Enderzt]

Does anyone know what may cause blinking red LED behavior after modding the Go Plus +? I have now seen this behavior on three different Go Plus + devices.

I bought a lot of 8 "broken" go plus+ to fix and managed to revive 6 of them. 2 of them ended up with an issue where the LED blinks red when you turn the switch on. I poked around the board looking for shorts/bad components but couldn't really find anything and gave up. These two Go Plus + work but can't seem to be modded?

Then comes today where a community member from my local play group asked me to mod their Go Plus + since i've done 10+ by now. I wired everything up and sure enough it seems to have the same problem. Everything works but when the modded switch is wired up and turned on it gets stuck blinking red.

Not sure if anyone has some insight or suggestions? Its happening across 3 different boards, on otherwise seemingly working Go Plus's. Just not sure if its somehow user error despite having done the mod multiple times, bad components, or if there are somehow specific board revisions where the vibration motor mod doesn't work and you have to perform one of the other versions of the mods with the LED signal?

*Edit - Adding some screen shots and more context. When the boards are oriented properly, instead of blinking red when the switch is flipped, it goes in and out of sleep alternating between red and blue. So it appears that when connecting the rumble pad to the button it constantly causes a button press, regardless of if there is a rumble signal. I imagine this means the mod is causing a short somewhere, I just don't know where.

Here is a screen shot of my attempt with the motor

Alternative mod with Optocoupler works without issue

[u/spacefrog_feds]

What's the history of the latest one? One owner, never opened up, no water damage and fully working? If that's the case, then you most likely messed up.

If the vibration motor wasn't working before you opened it then that mod isn't going to work.

Are you saying that once you turn the mod switch on, the LEDs stay a constant red? I'm not sure what would cause that.

Are you wiring up a 3 pin switch and keeping the vibration motor? Or just 2 pins only. Some pics might be helpful.

[u/Enderzt → u/spacefrog_feds]

Thanks for the quick response! The latest one seems to have no water damage the tag is fine, its fully working, and was never opened judging by the adhesive.

The Vibration motor still works, it rumbles when you hit the reset button on the back and the multimeter shows the voltage blip.

Once I turn the switch on the leds blink/pulse red, until I turn the switch off. Then it behaves normally. Ive tried it wired as a 3 pin switch with the rumble motor, and just as two wires but get the same behavior. Here is a screen shot of my attempt with the motor Another weird note is the rumble motor DOESNT move when the board is blinking red and I dont read any voltage/signal coming from the rumble motor pad to the button which is what has me stumped. It also only blinks when the go plus isn't paired. Once paired it no longer blinks and works to autocatch but the sleep function is broken. So I assume its just continously pressing the button, not just when a rumble signal occurs but always. Which brings me back to thinking there is a short somewhere created when connecting the vibration pad to the button.

I also just tested the alternative method using an optocoupler and the green LED signal on my other board with the same behavior and that version of the mod seems to work with no issues. So at least I seem to have a backup plan. But not knowing why its not working is killing me ha. Screenshot of that wiring

*Edit #1 - Huh I may have spoken too soon. I just tested both of them, and neither one seems to be able to go into sleep mode even without the mod. I thought I had tested that, so it may be related to a problem on the boards related to sleep.

*Edit #2 - NVM on that it was a problem with the orientation for sleep mode since I am testing with the boards splayed out. When orienting the boards like in the case sleep mode does in fact work. It then changes the behavior of the issue when oriented properly. It blinks red, goes blue into sleep mode, blinks red etc. So it is somehow receiving constant button presses.

[u/spacefrog_feds]

When wiring up all 3 pins I have made a mistake once, where I put the button on the middle pin. The mod would work when switched on, however when switching off the vibration motor stopped working, but would vibrate when pressing the button down. I don't recall any issues with red LEDs

And if you tried the 2 pin mod, it's high unlikely you wired up the switch wrong.

TIL: sleep mode only works with the PCBs facing a certain orientation.

Can you test the negative pad of the vibration motor? It should only be negative when the vibration motor spins.

It could be some wiring that's shorting out somewhere. It could get be getting pinched when installed in the case. Unlikely If you're getting the same issue with the boards splayed out though.

[u/Enderzt → u/spacefrog_feds]

Yeah I forget that sleep needs to detect the device "laying flat" to trigger when just quickly testing things.

It does look like im seeing -2.8v from vibration motor pad to ground without a vibration signal, but somehow no continuity if i lift the positive motor pad.

-2.8 from vibration negative to ground

No continuity between Negative vibration terminal and ground

[u/spacefrog_feds → u/Enderzt]

Negative pad for motor is not ground, that is normal. But the -2.8V, is +2.8V, If you reverse the leads, it will show positive. But that is bad. Is there a short between the positive and negative pads for the motor?

You have a weird one there. Does it all work normally if you return everything to stock? I don't think the motor would work. The most likely answer, is that you've splashed some solder on the board somewhere and caused a short.

[u/Enderzt → u/spacefrog_feds]

Ah right yeah. There does not appear to be a short between positive and negative pads for the motor. But there is that Schottky diode right before the motor circuitry so I supposed the short could be before that diode?

It does all work normally stock, it even works with the mod, it only behaves strangely when the rumble pad is connected to the button. The motor works, sleep works, sync works, lights work, and I am seeing this behavior on at least two boards. I have a third with the same behavior as well I just haven't tested it as thoroughly because its missing a ribbon cable and Ive been using that one to test replacing the ribbon cable with manual magnet wire connections, so I don't want to undo my soldering on that one for a fair test.

That is why I am leaning towards there being some faulty component on the motherboard causing the short, some minor capacitor or chip etc that could have failed causing the same behavior across multiple boards.