My Dream Aleph 2 Coming True - Page 12

JPDuarte · 12:03 AM

Quote:

Originally Posted by BobEllis

OK, I have no idea what you measured, but lets start here:

What is the voltage across R13? This should be rail-9.1.

5.6v

What is the voltage across R14? Should be ~4V[/QUOTE] 0.00v

What is the voltage to ground at Q1 and Q2 source pins? Should be ~4V[/QUOTE] Q1= 6.04v Q2= 6.04v

BobEllis · 30th October 2010, 12:04 AM

The source voltages are high.

R11 still 0V?

how about the others I asked for?

Bill Fuss · 30th October 2010, 12:05 AM

Gotcha, carry on.

JPDuarte · 30th October 2010, 12:09 AM

Quote:

Originally Posted by BobEllis

Bill, I'm just working off the board image and imagining the schematic.

Not Brian's latest board, but may be an early version.

Sure they are an early version, I got them 02 0r 04. _MG_2638.jpg

JPDuarte · 30th October 2010, 12:11 AM

Quote:

Originally Posted by BobEllis

The source voltages are high.

R11 still 0V?

how about the others I asked for?

0.0 mv

BobEllis · 12:21 AM

Let's get them all in one post, please.

Also measure across R12.

Post a picture of the bottom of your board. I suspect a solder bridge G-D on Q3

Also, please post rail voltages.

So, we need:
Rails
R11 = 0 Should be ~5
R12 should be 0
R13 should be rail -9.1
R14 should be ~4V

JPDuarte · 30th October 2010, 12:46 AM

Rails =48 , R11= 0 v , R12 = 0 v , R13= -5.49 , R14=0vAleph2_SolderSide.jpg

BobEllis · 12:57 AM

Guess I should have specified a picture of your assembled board.

R13 - is that top to ground? Something is wrong there - the junction of R13 and Z5 should be 15V above ground. With power off, measure the value of R13.

Are the rails symmetric - +/- 24V?

So your CCS isn't working. Replace the zener with another. Then we'll have to look at Q3.

Bill Fuss · 30th October 2010, 12:59 AM

I believe he has 48V rails, or thats what they should be for an Aleph 2.

BobEllis · 30th October 2010, 01:03 AM

Oh, in that case R13 should have around 39V across it.

Any ideas how he can have 48V rails, with .7V across Z5 and 5.5V across R13?

Did you measure the rails recently?

Are you measuring DC volts?

30th October 2010, 12:15 AM	#116
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	Let's get them all in one post, please. Also measure across R12. Post a picture of the bottom of your board. I suspect a solder bridge G-D on Q3 Also, please post rail voltages. So, we need: Rails R11 = 0 Should be ~5 R12 should be 0 R13 should be rail -9.1 R14 should be ~4V Last edited by BobEllis; 30th October 2010 at 12:21 AM.

30th October 2010, 12:54 AM	#118
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	Guess I should have specified a picture of your assembled board. R13 - is that top to ground? Something is wrong there - the junction of R13 and Z5 should be 15V above ground. With power off, measure the value of R13. Are the rails symmetric - +/- 24V? So your CCS isn't working. Replace the zener with another. Then we'll have to look at Q3. Last edited by BobEllis; 30th October 2010 at 12:57 AM.

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30th October 2010, 12:04 AM	#112
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	The source voltages are high. R11 still 0V? how about the others I asked for?

30th October 2010, 12:05 AM	#113
Bill Fuss RIP Join Date: Oct 2005 Location: Central Florida	Gotcha, carry on.

30th October 2010, 12:46 AM	#117
JPDuarte diyAudio Member Join Date: Jan 2010 Location: Providence. RI	Rails =48 , R11= 0 v , R12 = 0 v , R13= -5.49 , R14=0vAleph2_SolderSide.jpg

30th October 2010, 12:59 AM	#119
Bill Fuss RIP Join Date: Oct 2005 Location: Central Florida	I believe he has 48V rails, or thats what they should be for an Aleph 2.

30th October 2010, 01:03 AM	#120
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	Oh, in that case R13 should have around 39V across it. Any ideas how he can have 48V rails, with .7V across Z5 and 5.5V across R13? Did you measure the rails recently? Are you measuring DC volts?