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I've killed my gertboard ! ( and havent even finished it )

Former Member

Well this is amusing.. Whilst attempting to solder one of the grains of sand in the kit,  I've managed to burn a couple of surfacemount pads on the board  image.  It's on one of the resistors,  I think I had the iron way to hot.

 

I was wondering ( hoping )  if anyone could advise on a way to fix it..

 

Thanks in advance.

 

 

Ash.

Parents Reply
  • in reply to Former Member

    According to the Gertboard schematic from rev 1.0 of the Gertboard User Manual, R1 and R2 are both pull-ups to +3.3V.  So I think you can just connect the labeled ends of R1 and R2 using a short non-insulated jumper wire.  For the other end of R1, you could scrape the solder resist off the diagonal trace and solder a short bare wire to the exposed trace.  You'll need a sharp X-acto knife or equivalent and stop scraping as soon as you see metal.  Then pre-tin the trace by heating it up with your soldering iron while melting solder onto the trace.  This makes it much easier to solder the actual wire to R1.  Be careful not to short to the copper fill beside the trace.

     

    You could also make the repair on the back side of the board, soldering one end of R1 to the through-hole pin it's supposed to pull up (J11 pin 4) and solder an insulated wire to +3.3V (J7 pin 2) from the other end of R1.

Children
  • in reply to johnbeetem

    Brilliant, thanks :-)  I dont feel quite so sad now, I was thinking of the bin for it ....

     

    I'll have a stab and post back..

     

    The new iron is much better, so hopefully I can finish the board without any further problems

     

     

    Ash>

  • in reply to johnbeetem

    just a thought.....  could I use a standard 10K resistor in place of the SMT one?

  • in reply to johnbeetem

    just a thought.....  could I use a standard 10K resistor in place of the SMT one?

  • in reply to Former Member

    ash068 wrote:

     

    just a thought.....  could I use a standard [axial] 10K resistor in place of the SMT one?

    Sure, totally.  1/8 watt is a good size for a 10K pull-up to 3.3V, though it doesn't hurt to go larger.  You can strip the insulation off some spare wire and put it over the resistor axial leads.  You'll want to put it on the back side of the Gertboard.

  • in reply to johnbeetem

    Superb,  Thank John, you have been very helpful.  Off to my local shop for a resistor.

     

    Thanks

     

    image

  • in reply to Former Member

    As John Beetem says, the schematics show R1 connected from the 3.3V supply to the CSnA pin on J11. J11 is not easy to make out, but it is in the group of header pins next to the GPIO header pins.

     

    CSnA is clearly marked on the top of the board (the R1 side) as the second pin in from the end near R1. R1 and R2 are interconnected at the other end and are connected to the middle pin of J7 which is the 3.3 V set of three header pins for connecting the supply to the rest of the board. I have confirmed that R1 and R2 are connected at one end and to 3.3V with a meter, and also that R1 is connected to CSnA. R2 is connected to CSnB which is the last pin on the header. If there is anything left of the R1 connections on your Gerty you can confirm this for yourself.

     

    CSnA is clearly marked under the board, as well. The three pins on the 3.3V header are not marked, but easily found. I suggest making the wired resistor connection under the board to these two points. When you are done, make sure there is absolutely no connection to the two outer 3.3V supply pins. Please make sure that both of the resistor wires are fully insulated (with tubing or plastic stripped from a wire). Just leave very short bare ends for soldering. Any problem on the 3.3V side will destroy your Raspberry Pi, so check and check again and test for unintended connections.

     

    Roy Leith

  • in reply to royleith

    Hi Roy,

     

    Thanks for your efforts.

     

          I've fixed the issue using John's advice. I soldered a resistor to the underside of the board, there are two 3.3v pins near to the CSnA pin, so I used that. some insulation tape on the board under the resistor took care of the insulation.