damaged mm (baite) board, D2?

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.

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

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

(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.

I’m honored to be in such company. I think this will work?

http://m.aliexpress.com/item/32541620627.html

Thanks for all the info!

Oh ! Even cheaper than what I’ve paid …

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.

http://cpc.farnell.com/unbranded/vtmg6/ … dp/PY31106
http://cpc.farnell.com/linear-tools/59- … dp/PY31675
£11 — £13 ukp
i’ve also a set of the spectacle type, tried them on, un-used since.
i use the second, but i also have ‘reading’ glasses of 2.00 and 3.00 which combined the above means i need to be careful of the soldering irons’ hot barrel.
stephen

zmemw16 wrote:http://cpc.farnell.com/unbranded/vtmg6/ … dp/PY31106
http://cpc.farnell.com/linear-tools/59- … dp/PY31675
£11 — £13 ukp
i’ve also a set of the spectacle type, tried them on, un-used since.
i use the second, but i also have ‘reading’ glasses of 2.00 and 3.00 which combined the above means i need to be careful of the soldering irons’ hot barrel.
stephen

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

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?

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 (160.88 KiB) Viewed 352 times