[BUILD] New FET/RACK Official Help Thread - Please read first post!

[Maxwell.ravitz]

ok, flipped the caps and it removed the dc in the output knob.  I'm still hearing a slight click when I turn the knob completely ccw, almost like I can hear the audio click off, it's minor, but wouldn't mind figuring out what it is.  or is that normal behavior, and I'm being finnicky?  Happy to be almost done! . Thanks for the quick help.

 

[Echo North]

ok, flipped the caps and it removed the dc in the output knob.  I'm still hearing a slight click when I turn the knob completely ccw, almost like I can hear the audio click off, it's minor, but wouldn't mind figuring out what it is.  or is that normal behavior, and I'm being finnicky?  Happy to be almost done! . Thanks for the quick help.

On the output?  Pots always have a little end of track noise.  If it's at the end that should be well out of operational range.

Mike

 

[bjohnsonaudio]

Q7? VDC?

I have no idea. You could remove it and try the transistor diode test.

http://www.hairballaudio.com/uploads/pdf/fet_rack_a_v1.14_voltages.pdf

You may want to reflow and double check everything in the GR Amp.

Hey Mike! So I went through and checked the DC Volts of my GR Amp part of the PCB. The resistors are the right resistors and the Diodes are in the right polarity. My transistors are not checking out at this part of the board.

My readings are

Q7 - B = 16.17 DC V
E= 23.64 DC V
C= 27.4 DC V

Q8 - B = 27.41 DC V
E= 26.91 DC V
C= 30.52 DC V

Q9 -
B = 4.97 DC V
E= 4.37 DC V
C = 5.3 DC V

Q10 - B = 5.3 DC V
E = 4.69 DC V
C = 30.53 DC V

The transistors on the rest of my board checked out great, it is just this part of the board I am trying to figure out. I went and checked my solder and did some reflow but I am still getting the same readings.

Let me know if this is clear and again I appreciate your patience and support!

 

[Echo North]

I would guess you have something like a 4.7K, 47K, 470K mix up (there are many in the section) or one of those transistors is bad.

You could carefully pull and test them as described in that link. I would start with Q7, seems like that might be blown out.

Something is out and cascading through the circuit.

Mike

 

[Maxwell.ravitz]

On the output?  Pots always have a little end of track noise.  If it's at the end that should be well out of operational range.

Mike

ok cool, then I'm up and running!  8) Thanks again for all of your guidance and quick help!

 

[Echo North]

ok cool, then I'm up and running!  8) Thanks again for all of your guidance and quick help!

Enjoy!

 

[bjohnsonaudio]

I would guess you have something like a 4.7K, 47K, 470K mix up (there are many in the section) or one of those transistors is bad.

You could carefully pull and test them as described in that link. I would start with Q7, seems like that might be blown out.

Something is out and cascading through the circuit.

Mike

Hey Mike! I figured it out, and it is working awesome! So I put in the 1k ohm and belows first. I ended up receiving 270k resistors instead of 270 ohm resistors. Since I saw 270 when measuring I must have thought nothing of it when I stuffed them.

I appreciate all of your help with this (I know it was a huge learning experience for me). Just heads up on your end, my build kit didn't have fuses and I got a wrong measurement for the 3.9 M resistors (4.2 ohm I think it was I got and I sent in a missing parts report). But after finding this I see that I was given 270k instead of 270 R. I should have caught it right away and I would have saved myself so much headache!

Also when calibrating the needle between -10 and 0 should I expect it to not be precise? I seem to be slightly off when I switch back and fourth but not by much.

Thanks again!

 

[Echo North]

Hey Mike! I figured it out, and it is working awesome! So I put in the 1k ohm and belows first. I ended up receiving 270k resistors instead of 270 ohm resistors. Since I saw 270 when measuring I must have thought nothing of it when I stuffed them.

Ahhhh ya I thought we'd caught all those.  We had a temp guy doing kits and it's been a bit of a mess to clean up.

I appreciate all of your help with this (I know it was a huge learning experience for me). Just heads up on your end, my build kit didn't have fuses and I got a wrong measurement for the 3.9 M resistors (4.2 ohm I think it was I got and I sent in a missing parts report). But after finding this I see that I was given 270k instead of 270 R. I should have caught it right away and I would have saved myself so much headache!

Ya it's been a mess. Sorry about that.

We have been re-checking every single kit now to make sure all the kits are perfect.  Email me if you want a second one, I'll cut you as much of a deal as I can.

Also when calibrating the needle between -10 and 0 should I expect it to not be precise? I seem to be slightly off when I switch back and fourth but not by much.
Thanks again!

It takes a second to settle and it may drift a little between power ups, but it should be close.

Mike

 

[bjohnsonaudio]

Hey Mike.

Someone who bought my compressor sent me a message saying that when using an 8:1 ratio with about 5db GR that his waveform looks a little lopsided ... like DC offset but not that. He said everything sounds great he just is wondering what that is.

Do you have any idea what that could be or if that is normal?

Thanks for your help!

 

[Echo North]

Hey Mike.

Someone who bought my compressor sent me a message saying that when using an 8:1 ratio with about 5db GR that his waveform looks a little lopsided ... like DC offset but not that. He said everything sounds great he just is wondering what that is.

Do you have any idea what that could be or if that is normal?

Thanks for your help!

Probably asymmetrical clipping. Which is desirable and part of "color". 

Or could just be nothing, the protools waveform is just a computer representation of what the software thinks the waveform look like.

Mike

 

[bjohnsonaudio]

Probably asymmetrical clipping. Which is desirable and part of "color". 

Or could just be nothing, the protools waveform is just a computer representation of what the software thinks the waveform look like.

Mike

Thanks!

 

[bjohnsonaudio]

Hey Mike. We are back at it again. I am building my new Rev A compressor and again I'm having difficulty with the power supply.

I checked all of my solder joints and they all look solid. I checked my resistors and they are correct. My diodes and caps are the right polarity.

I checked the AC Voltage of my IEC input and I am reading 120 VAC when I check the "L" Connector. I am also getting 120 VAC when I check my voltage select switch and I am getting a 120 VAC reading at the "Do" pin. I checked the resistance on my Power Transformer cables and they all read the same numbers. However when I check the AC at Main PCB board (checking the orange and yellow wires when everything is connected and turned on) I am not getting any reading...about 2.7 Milivolts so I am getting no power to the main PCB.

What in the world do you think is going on?

I can't seem to get a smooth build going can I

 

[scott2000]

However when I check the AC at Main PCB board (checking the orange and yellow wires when everything is connected and turned on) I am not getting any reading...about 2.7 Milivolts so I am getting no power to the main PCB.

What in the world do you think is going on?

I can't seem to get a smooth build going can I

Is it supposed to be AC there??? Are you talking power board ???  Where are these test points? I don't see them on the schematic...

 

[bjohnsonaudio]

Is it supposed to be AC there??? Are you talking power board ???  Where are these test points? I don't see them on the schematic...

Quote from: Hairball Audio on February 05, 2018, 05:04:33 PM
Those two orange and one yellow wire connect to the right angle connector that makes the connections to the main PCB.  What is the AC voltage at those connections between one of the oranges and yellow, and the other orange and yellow. You can use the pads on the PCB that correspond to the connections to test the AC.

 

[scott2000]

Quote from: Hairball Audio on February 05, 2018, 05:04:33 PM
Those two orange and one yellow wire connect to the right angle connector that makes the connections to the main PCB.  What is the AC voltage at those connections between one of the oranges and yellow, and the other orange and yellow. You can use the pads on the PCB that correspond to the connections to test the AC.

I'm sure Mike will step in and answer. I'm pretty impressed with how active he is here.

I'd have to look at the building notes to make sense of what is being measured and where but, my thought and question was that, even if there is no or minimal ac present somewhere, the main board may be getting the proper B+ (DC)???? But, I'm not sure if that's the main board you are even talking about.....or where that test spot is.....pre reg...etc..

Sorry to add any confusion to your issue...lol


edit___/// ok I see you've had a similar issue in the past and, if you're measuring right, it sounds like an issue...

I'm guessing you've re read the info you have from before and checked everything? .....I see you mention the transformer measures right...... 

I don't have one of these yet but have been following a lot of the builds so I can be prepared when I do.....

They seem pretty straight forward but there are a lot of areas that can be missed accidentally....

Good Luck!!!

 

[nolanthies]

Check your relay and ratio PCB connectors.  Make sure all the solder joints look good and reflow/test again.

Mike

Ended up getting my tech to go thru it, and now everything is good.  Only weird thing is it seems like somehow my ration PCB is upside down (20:1 sounds like 4:1, and vise versa).  The cable is obviously only long enough for it to be installed one way, and it looks like the harness connection to the main PCB is oriented correctly.  Anything else stupid I could have done here? 

 

[bjohnsonaudio]

Hey Mike. We are back at it again. I am building my new Rev A compressor and again I'm having difficulty with the power supply.

I checked all of my solder joints and they all look solid. I checked my resistors and they are correct. My diodes and caps are the right polarity.

I checked the AC Voltage of my IEC input and I am reading 120 VAC when I check the "L" Connector. I am also getting 120 VAC when I check my voltage select switch and I am getting a 120 VAC reading at the "Do" pin. I checked the resistance on my Power Transformer cables and they all read the same numbers. However when I check the AC at Main PCB board (checking the orange and yellow wires when everything is connected and turned on) I am not getting any reading...about 2.7 Milivolts so I am getting no power to the main PCB.

What in the world do you think is going on?

I can't seem to get a smooth build going can I

Hey Mike. Just following up on this issue that I am having with my Rev A. Wondering if you had a chance to give it some thought?

Thanks!

 

[Echo North]

Hey Mike. Just following up on this issue that I am having with my Rev A. Wondering if you had a chance to give it some thought?

Thanks!

You have your old build there?  If so, the easies option is to swap out components to see what the issue is (power transformer, V select PCB, Meter PCB).

Mike

 

[Echo North]

Ended up getting my tech to go thru it, and now everything is good.  Only weird thing is it seems like somehow my ration PCB is upside down (20:1 sounds like 4:1, and vise versa).  The cable is obviously only long enough for it to be installed one way, and it looks like the harness connection to the main PCB is oriented correctly.  Anything else stupid I could have done here?

Read through the operational FAQ. Your answer is in there.

http://www.hairballaudio.com/blog/resources/post/fetrack-operational-faq

 

[bjohnsonaudio]

You have your old build there?  If so, the easies option is to swap out components to see what the issue is (power transformer, V select PCB, Meter PCB).

Mike

Hey Mike! I wish I did have my old build, but I do not.