New to Soldering - checking solder joints Pro Mini

Other Hardware General Electronics
1

Hello,
sorry for my trivial question but I was not able to understand the schematics of the Sparkfun Pro Mini.
Practically, I have started soldering for the first time and I begin with the Pro Mini (maybe not a good idea).
Pics attached.
Because of my unsteady hand, I wanted to check the joints through the continuity test of my multimeter.
I did two types of checking

  1. the same joint one lead to the header on the front and one lead over the solder on the back
  2. two adjacent joints to see if I created an unwanted bridge

I notice that everything seems fine except for BLK and the adjacent GND. There is continuity between these two joints. Is it ok or did I mess up?

Thanks

promini_2.JPG

promini_1.JPG

2

What does the schematic for the Pro Mini show ?

3

Did you reverse the probes to see if you are measuring a diode?

Paul

4

srnet:
What does the schematic for the Pro Mini show ?

it should be this:
link
but I cannot find the pin called BLK, hence, I do not understand how to read it.

5

Paul_KD7HB:
Did you reverse the probes to see if you are measuring a diode?

Paul

Do you mean as a general rule to check two adjacent joints?
I did now, but I have no seen any difference.
Still, BLK and GND have continuity
thanks

6

AntroxEv:
I cannot find the pin called BLK, hence, I do not understand how to read it.

Which of the connectors on that schematic looks most like the programming connector on the Pro Mini ?

A good clue is that the Pro Mini programming connector has 6 pins ......................

7

srnet:
Which of the connectors on that schematic looks most like the programming connector on the Pro Mini ?

A good clue is that the Pro Mini programming connector has 6 pins ......................

It shpuld be JP1 (FTDI basic) and although the order is completely different, by exclusion, BLK could be denoted as DTR. In any case, I cannot see any connection between them. So, I should not have continuity?

8

Just tried the same test on a spare pro mini.
The same thing, hence it should not be a problem of my soldering, hopefully.

9

You have found the right connector, and the order is exactly as expected, its standard for a Pro Mini.

Note the pins (on the schematic side) are labelled;

GND, GND, VCC, RXI, TXD, DTR.

What do the names suggest ?

10

srnet:
You have found the right connector, and the order is exactly as expected, its standard for a Pro Mini.

Note the pins (on the schematic side) are labelled;

GND, GND, VCC, RXI, TXD, DTR.

What do the names suggest ?

Found here (it is JP2 so not sure if the schematic is the same but it seems so) :

So, it seems that BLK is GND and they are connected (as illustrated in the pic). Interesting

11

Rather than show a new schematic image it would be best to stick to comments on the schematic you linked to at post #3, less confusing that way ?

12

"BLK" may be Chinglish for "BLANK". But if connected to ground, it is not blank.

Paul

13

srnet:
Rather than show a new schematic image it would be best to stick to comments on the schematic you linked to at post #3, less confusing that way ?

You said the order is correct, hence BLK corresponds to GND.

14

Paul_KD7HB:
"BLK" may be Chinglish for "BLANK". But if connected to ground, it is not blank.

Paul

I found it in ADUFRUIT that BLK stands for black "(Black BLK wire on FTDI Cable)" and corresponds to GND.

15

The outer two pins of the connector are labelled with the colour of the wire that is used on many FTDI serial - USB cables, rather than the signal names that are used on the rest of the pins.

GRN = Green
BLK = Black

This is done to aid the user in connecting the connector in the correct orientation

16

One more question about checking joints,
in the case of desoldering or cutting the trace of the LED.

I did not manage to desolder it and I am worried to have touched with the hot iron other adjacent components.
In the end, I just managed to break the LED with a knife and the upper part slipped over.
The board seems still working without the LED.

  1. do you have a figure of the Arduino pro mini I am using (see pic in post #1) with the definition of each surface component?

  2. Could I check with a multimeter if I damaged any components?

Thanks