Pic Burner-help on R1 signal path

Testing/Troubleshooting
1

:slight_smile: Hello to all

As i’m building a Midibox SID i’m getting troubles assembling the Pic Burner on a predrilled board.

Following the schematic from http://www.ucapps.de/mbhp/mbhp_burner.pdf we can see that:

Resistor R1 (220ohm) is connected to the OUTPUT pin of LM317, then is connected to the trimpot P1 (2.2k).

The central pin of P1 is connected to ADJUST pin of LM317.

My answer is: why this doesn’t happen on PCB’s Burner layout?

http://ucapps.de/mbhp/mbhp_burner_v1.gif

On it we can see that resistor R1 goes to Ground and not to P1. In that way only one copper track goes to P1 central pin from ADJUST LM317’s pin, and nothing comes from the resistor R1.

Let me know so i can go on :-).

Gord the Rogue

2

You cant see the trace on the GIF, dl the *.brd file and hide the top layers, there is a trace that goes to the from R1 to the 78L05.  I made a board based on this and it works fine

3

Following the schematic from http://www.ucapps.de/mbhp/mbhp_burner.pdf we can see that:

Resistor R1 (220ohm) is connected to the OUTPUT pin of LM317, then is connected to the trimpot P1 (2.2k).

The central pin of P1 is connected to ADJUST pin of LM317.

I never told about 78L05, i’m talking about R1 not R2.

Btw i will try with Eagle, thx

4

You can click the traces and they will highlight what pins they are connected to. May make things easier to sort out

5

I think this was a typing error - Altitude is right, R1 is connected correctly to the LM317, but it’s hard to see it without eagle.

Best Regards, Thorsten.