Replace either the LED or more likely the C1815.  That's usually the culprit for me. 

 

Edit:  Very nice Kerry and nice work on the mini boards.    Mine didn't light up the CCS but then I didn't bother to get it working.  The PCB was correct though so some part was faulty. 

Edited June 28, 201312 yr by spritzer

if the outputs are at +VCC then probably Q20 is shorted.

 

or the led is toast.

 

Need to know the voltages at the top of D11 and D12

Edited June 28, 201312 yr by kevin gilmore

if the outputs are at +VCC then probably Q20 is shorted.

 

or the led is toast.

 

Need to know the voltages at the top of D11 and D12

Not much... -240mV and -175mV. So what do I change? The C1815? The OK board shows ~10V at the top of the diodes.

Shorted 1815 or open led or led in backwards.

Shorted 1815 or open led or led in backwards.

Changed the 1815. Same symptoms. I don't have spare LEDs other than white. Would the voltage drop be too big while i wait for red to come in?

don't do that. go to radio shack if you have to.

 

white led's are 3.8 volts

Make sure that is really a 10k resistor feeding the led

I am red faced... I went to Radio Shack first thing in the morning to get LEDs, got home, heated up the iron to desolder the LED, only to realize that one of the LED legs was not soldered. How could I miss that?!? I put a bit of solder, turn on the amp and voila, all is well. Thank you for your guidance, now comes the fun of zeroing the outputs. Btw, for my voltage settings, the offset resistors are at the lowest setting so I may try a 1k in series with the pot.

  Things like that happen.  Hope all go well now.

Music! I still have plenty of work to on the casework before i can post pictures, but right now is a happy moment. Thank you Kevin for the design and the tips, lil knight and eggil for the boards, picaudio for some neat connectors, and the head-case community in general for the sharing your knowledge.

P.S: I replaced the 2k series resistor for the offset pot with 1.2k. Offest and balance on the outputs drift below +/-1V, close enough.

Correction: I didn't do squat besides helping distribute some of them.

Kevin and Birgir are the great guys behind this.

LilKnight is the driving force on making the boards.

I am very thankful for the wonderful sound coming out of my build.

Grats for getting it alive eslover! Now you get to enjoy the music

 

Kerry, I'm eagerly waiting to look at your completed results!

http://gilmore.chem.northwestern.edu/knobs2.jpg

http://gilmore.chem.northwestern.edu/knobs3.jpg

 

finished Arizona desert ironwood knob and

Hawaii burl red mallee blank with interesting voids

Very nice Kevin! I particularly like the burl.

Has anyone encountered an issue where LED at the input stage doesn't light up until after your power the psu down? Could it be that I installed something backwards?

 

Clarification- it briefly lights up during when I first power things up, then fades after about half a second.

Me too.  I love the burl, but both are beautiful.

My goodness. That is art

Got the heat sinks in today.  Here's how it's going to lay out...

 

Got the new mini PSU powered up fine Voltage is pretty much right on.

I am using new devices, ksc5026 and ksa1156, instead of the 2sc3840 and 2sa1486.

 

That's good as we reworked a lot to make it so small.. 

Good job all round gentlemen. Will you make the pcb available to us now?

And thanks for the post Kerry. That is an inspiration!

shrunk kgsshv power supply board available to anyone that wants them, but lil-knight has them so

boards will be available from him.

Love the floor tiles Lil Knight.

 

 

well if you already start on the floor you have less far to fall when you get knocked on your ass

if you make the mistake of touching any of the high voltage wires