Re: R15 and ADE-1 mixer getting very hot
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Check for a solder bridge or a tiny copper trace that remained when the pcb was etched. You can use a magnifier or a meter to check it. What you might also do is to run a knife between the tracks to remove any tiny bridge that may not be easily visible. I also had a piece of equipment where the pcb would short after some time and if you switch off and leave it for a few minutes it would go open again and then again short after a few minutes. I had to isolate the respective contact, strip a little bit of track and connect the component a little furtehr because it appeared to be some contamination in the material itself shorting after a few minutes. You learn by experience when things do what they shouldn't do. Regards Lawrence
On Thu, Apr 27, 2017 at 2:47 AM, William Hemmingsen <lee.hemmingsen@...> wrote:
R15-c17 junction to ground is 13.3k.? I removed c17 and no change.? FYI R11 & Q7 are also removed.? So this resistance is 100% in the ADE-1 itself (as its the only thing left). If I recall correctly, when R11 is in the circuit the resistance is 2k as expected. Even with R11, Q7, C17 out of circuit R15 gets burn you hot when you apply 12v. Also my ADE-1 is mounted the same as your attached picture. I took a brand new ADE-1 from reel and measured resistance from pin 1 to 2 = 20k? & pin 1 to 5 = 40k.? if I remove R15, the ADE-1 on the board matches this.? This makes no sense, because those resistances should limit current.? My guess is the resistance goes down when the diodes are biased...Just a wild guess.? But when 12v is applied R15 heats up like there is a short. With all components installed; When power is applied I measured the voltage at R15-c17 junction which equals only 1.5v (it should be close to 12v correct?).? Gate voltage of Q17 is only .7v. ? So this would leave me to guess that when power is applied the ade-1 must go to ~12 ohms to drop the voltage that much.
I'm lost
W4WHL
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