Help with Speedball

[jt]

I have installed Speedball and one LED does not light up - the D2 LED in the left PC board.

The following voltages are off:
T1: 170
T7: 170
T20: 0
A6: 0
B1:170
B3: 170

I double checked LED orientation before soldering.

 

[PassionForSound]

Have you checked all of your solder joints for good, shiny finishes with sufficient solder, but not too much?

 

[jt]

Yes I checked the soldering, board connections and resistor placement. Unfortunately couldn't confirm LED orientation since the LEDs are flush mounted to the board.

 

[jt]

On closer inspection that D2 LED is working but it's very faint. I plugged in some old phones and the left channel has low volume. Right channel sounds ok.

 

[sjeffrey]

T20 should be 0V, there is a typo in the Speedball manual.
See here: http://www.bottlehead.com/smf/index.php/topic,1398.0.html

Make sure that the transistor (MJE350) on the small board has the writing on the left side.
double check the resistors are on correct board, the 2 small ones are easy to mix up.

 

[Paul Birkeland]

Neither of your small PC boards is functioning correctly.  Possible causes are:

LED's in backwards (the silver stripe should be visible)
Transistors in the incorrect positions (especially the 2N2222/2N2907)
Smaller pair of resistors is swapped

Feel free to post some pics and we may be able to spot what's going on.

-PB

 

[jt]

You are right PB. I have two transistors swapped. What is the best way to remove these? I have some solder wick but don't know if it will work. Thanks, JT.

 

[sjeffrey]

Just heat up the solder at each lead and pull gently.  It's easier if you can have a friend gently pull while you heat up the joints.  Some wick will also help.  Remove as much as you can, then pull...

 

[2wo]

Don't try it in one go. hold the body with one hand and heat one lead while applying light tension on it till it moves a little. Then do the same with the next lead, 2 or 3 go around's and you walk the transistor right out. just be gentle and let cool if the body gets hot...John

 

[jt]

Swapping transistors fixed the problem! Thanks for all the help guys.

I had a hell of a time removing the transistors. Did some googling and came up with this approach which worked a treat - use solder sucker with a notch cut out of the end of the nozzle so the soldering iron tip can be in contact with the pin while the nozzle is flush with the board. Gives max suction and cleans the joint right out.

 

[Doc B]

Excellent tip, have to try that.