Spark Logic

damaged mm (baite) board, D2?

kolalde Thu Dec 10, 2015 5:38 am

Not sure how I did it, but it seems like I damaged my maple mini clone (baite BTE14-07). Monkeying around on the breadboard I’d most likely.

When I attach a USB cable the board doesn’t power up. I checked the cable and USB supply, both OK.

With the USB cable attached (into a powered hub at the other end) I measured 0V out of the lm1117 regulator. Looking at the schematic I guessed it was worth trying applying 5V to VIN. Frankly I don’t quite understand the dual-transistor circuit connected to PB9, so tried VIN first, which worked. Everything seemed to be functioning, I just can’t power the board from USB anymore.

Not a big issue since 5V for VIN, or 3.3V for VCC are both available on my desk, and when I finally get around to putting this into a project, I won’t be powering from the USB jack anyway, just kinda sucks I damaged it.

I measured the D2 diode, very high resistance in both directions. Could I remove the diode and replace with a solder connection (I don’t have any S4 diodes), but would that put my USB port at risk? If I never use both VIN and USBVCC would I be ok (just living with the risk of damaging my computer or hub USB port)? What purpose does the diode serve?

Can you tell I’ve never really done this before?

Thanks.

Replies

bianchifan Thu Dec 10, 2015 8:29 am

kolalde wrote: maple mini clone (baite BTE14-07)..

ahull Thu Dec 10, 2015 8:53 am

Welcome to the Magic Smoke club :D You should find this of interest. Lots of useful stuff and stories about mishaps with STM boards and the like.

martinayotte Thu Dec 10, 2015 2:57 pm

(I don’t have any S4 diodes)
Yes, Andy and myself purchased some of those S4 after our Magic Smoke club experiences, they are pretty cheap.

martinayotte Thu Dec 10, 2015 4:08 pm

Oh ! Even cheaper than what I’ve paid …

kolalde Fri Dec 25, 2015 9:30 pm

Well that was mighty small. I was going to take a couple pictures, but I don’t have anything that will make something that small clear enough to see. Still not sure how I did it, but the new D2 S4 diode restored my being able to power the board from the USB. 99 grains of diode salt left over.

I think I’ll get a late Christmas present, something to add light and magnification.

zmemw16 Sat Dec 26, 2015 5:04 pm

i suspect depth perception is affected as well?

do you ever think must find the dremel and convert these lens to bi-focal or is it the 6x you’re after?
as i’m normally at 2x for the laptop, for the kindle & bread boarding i need the x3 and for smd the band as well with it ‘s range of magnification.

don’t know if you can, have a look at january nuts & volts p55 fig 2 is what i thought you could use to calc/estimate when to shut off

stephen

ahull Sat Dec 26, 2015 7:39 pm

zmemw16 wrote:i suspect depth perception is affected as well?

do you ever think must find the dremel and convert these lens to bi-focal or is it the 6x you’re after?

zmemw16 Sun Dec 27, 2015 3:39 am

this is the sort of graph i was thinking you could use to check for rate of discharge changing as the
battery loses it.
battery-load.png
battery-load.png (160.88 KiB) Viewed 352 times

Sign in to reply