Electronics SMT components help

[renaissance_man]

I have a 10 LED sequencer board which uses two darlington arrays and astable/monostable flip flop (I only know this because I looked up the numbers printed on the chips)

The board has two other components I'm not sure about.
The first is the black component at the top of the board it has very faintly "B2" printed in white on top.
The second are the two capacitors, they have no values printed on them they are just brown.
Can anyone help identify the capacitance values and tell me what the black component is please?
If it's any help the board has 2 103 value SMT resistors and 1 000 value resistor.

Here's a picture:

Thanks

 

[propmaster2000]

Hi renaissance_man,

I looked over your picture of the circuit board and it looks like the
4047 is set up with multiple clock outputs from pins 13 (OSC out), 11 (Q[not], and 10 (Q).
Below is a link to a schematic of a astable/monostable multivibrator circuit.
It may give you some clues as to what the R/C (resister/capacitor) values
might be.

Retriggerable Monostable

There appears to be an adjustable resister sitting beside the low value cap. in the upper left corner.

The 000 resister is used as a jumper.
The 103's are 10K resisters. (One is on the reset pin of the 4017).

The "black" component appears to be "inline" with the positive power source and may be a diode to keep the power from being applied in reverse and damaging the IC's.

The other capacitor (10mfd?) may be accross the Positive and Negative leads to filter any noise from the power supply (if not using batteries).

The 4017 also appears to be feeding one of the drivers (nearest to the chip) as well as having 10 direct lines out (without a driver).

I am no expert by any means, so I hope this helped a little...

propmaster2000

.

 

[exoray]

The "black" component appears to be "inline" with the positive power source and may be a diode to keep the power from being applied in reverse and damaging the IC's.

That would be correct likely a diode...

The other capacitor (10mfd?) may be accross the Positive and Negative leads to filter any noise from the power supply (if not using batteries).

Agreed if it's across the positive and negative it's just for filtering and value is not horribly critical in most applications... Just a hunch but it's probaly the same value as the other R/C one on the 4047 circuit...

 

[renaissance_man]

Thanks to both of you for the input.

My next question, as a novice would be, do you know what the part numbers for the diode and two capacitors would be on the Digi-Key website?
Long shot I know, but I really would appreciate yours or anyone's help with this.
Thanks

 

[exoray]

My next question, as a novice would be, do you know what the part numbers for the diode and two capacitors would be on the Digi-Key website?

Well you would need to establish the values you want...

Just a guess on the packages, from a quick look, one package size up or down will still generally work on most board layouts...

The caps appear to be 1812 package
The resistors appear to be 1206 package
The diode appears to be SOD-123

 

[renaissance_man]

I'm not really sure what values I would need, I plan on using a 6V battery to power the circuits.
I had a quick look on the Digi-Key site and there are so many different types of diode, and capacitor.
I'm in a little over my head, well more than a little.

Any suggestions?

 

[exoray]

Any suggestions?

Sure I can suggest values, but the timing and duration of the sequence might not match the original unless my suggestions just happen to be the same values they used...

For the pot I would use at minimum a 10KΩ up to a say a 1MΩ I would likely suggest somewhere in the middle say a 500KΩ...

For the caps I would say drop in 1000pf (.001uF) and see how it works, but it might not hurt to pick up some other values like 100pf(.0001uF), 10nF(.01uF) or even .1uF and given them a run if there is a timing issues as you are only talking pennies... Same with the filtering cap it's more of a safety feature than required in most instances so drop in a .1uF and call it a day unless you have stability issues...

For the diode Digikey part MBR0520LT1GOSCT-ND will likey work just fine, or it could honestly be left off...

Propmaster already gave you the resistor values, assuming the number he read off the picture is correct...