Author |
Message |
altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
|
|
Back to top
|
|
|
ashleym
Joined: Aug 20, 2009 Posts: 181 Location: uk
|
Posted: Sat Nov 03, 2012 3:19 am Post subject:
|
|
|
I can try to answer the power supply part of your question.
The 2 caps you are talking about (C13&14) are power supply by-pass capacitors. They by-pass the effect the local chip can have on the power supply. When the local chip needs some extra power it can draw this from the bypass caps without draining too much from the main supply because if it did other parts of the circuit could be effected. THere are other uses but that is for another day.
The earths on the circuit diagram are virtual earths. Ray has made these to be half way between +9 and 0V, the local virtual earth for this part of the circuit is section with R37 and R42. Wire back to that earth point.
Without testing the LED section my tip is to check the cap polarity and spin it round to check.
I hope this helps and I hope I have aimed my advice at the right level. _________________ http://soundcloud.com/for-mash-get-ash |
|
Back to top
|
|
|
altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
|
Posted: Sun Nov 04, 2012 10:10 am Post subject:
|
|
|
That's how I thought C13 and 14 were supposed to function. Will they work as supply bypass if I connect them as shown but also connect the pins directly to the supply rails? I got the impression that the caps were the only connection to the power pins.
I suspected that the R37 and 42 assembly was a virtual ground. Thanks for clarifying that.
For the LED section -- is R70 to positive and C26 to negative intended to minimize the LED's effect on the circuit? It's kinda hard to miss the polarity markings on a massive 470uf cap but I tried reversing it anyway. Even connected correctly it just seems to be creating too much resistance to the negative rail for the LED.
Thanks again for your help! _________________ Noise is for heroes! |
|
Back to top
|
|
|
ashleym
Joined: Aug 20, 2009 Posts: 181 Location: uk
|
Posted: Tue Nov 06, 2012 12:58 pm Post subject:
|
|
|
You dont NEED the bypass caps and if you arent sure what to do with them then leave them out.
If the LED isnt lighting properly make sure you have the right LED type or resistor value. Look at something like this
http://led.linear1.org/1led.wiz
Click the ? and you will see that different coloured LEDs have different forward voltages.
Always happy to help the trouble is I am not always right!! We all live and learn _________________ http://soundcloud.com/for-mash-get-ash |
|
Back to top
|
|
|
|