Voltage Issue for terminal 10

[wabibito]

Guys,

I recently built the crack with speedball, everything seems fine.  I added the triad and removed one of the 270ohm.  I also add the cree mod and removed the 4 rectifiers.  All the voltage seems fine except for terminal 10.  It is supposed to be 0 but it is sitting at 10-12v.  What could be the possible cause?

[Paul Birkeland]

That voltage is bled off by the 2.49K resistors on the headphone jack, and in the Crack 1.1 the headphone jack itself will also bleed that down.  I would suspect that you either have a bad solder joint at the headphone jack, or the wire leaving terminal 10 is loose.

[wabibito]

I have the crack version 1.0 with 1.0 speedball. I check all the solder joints and seems fine. I will check again. At first the reading is around 100v. But now it range from 10-13v.

[Paul Birkeland]

Are you sure your meter isn't showing 10mV?  (That would be 0.010V, which is close enough to zero)

[wabibito]

Thank you so much Paul. That was the first thing I checked and was hoping but the multimeter was on correct settings. All others voltage is in range.

The only thing connect to this terminal is white cable to the tip of head phone jack and the 100uF cap. I will try to reflow the solder again tonight to see. The ring on the jack read 0. Just the tip.

[Paul Birkeland]

Again, this voltage is bled off by the 2.49K resistor on the headphone jack.  The white wire you're referring to connects to the headphone jack.  Focus there.

[wabibito]

Unsolder those connection and resolver again seems to solve the issue. The amp sounds great.