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

[beaustep]

Few things:

1. Fuse is in?
2. All three L brackets have the PCB secured to the enclosure?
3. DMM set to DC?
4. Do you have <0 ohm of resistance between the transformer yellow lead pad and enclosure? (power off)
5. What are your +30VDC and -10VDC readings?

Mike

1: Fuse is definitely in. Double/triple checked.
2: All 3 brackets are secured.
3: DMM is set to DC
4. 0.2 ohms
5. 0.003VDC

 

[Echo North]

1: Fuse is definitely in. Double/triple checked.
2: All 3 brackets are secured.
3: DMM is set to DC
4. 0.2 ohms
5. 0.003VDC

1. You have 0.003 VDC at your +30 VDC test point AND you -10 VDC test point?
2. You have the unit turned on and plugged in correct? Meaning you have the GR pushbutton selected?
3. What is your AC V between the yellow secondary pad and each orange (give me 2 readings).

 

[stringmike]

Hi Mike.
Here’s what I measured:
TP1: 0.122V
TP15: 2.10V
Brown wire: 6.25V
Output xlr: 6.22V

Is this the Rev D?

Set your compressor controls:

Input: 12 O’Clock
Output: 12 O’Clock
Attack: GR OFF
Release: Full CW
Ratio: 20:1
Meter: GR
Signal: Sine 1kHz @ 0dBu (0.775 VAC across input + and -)

With your DMM measure AC at the following test points using the chassis as you reference (black probe).

TP1
TP15
BRN Wire on Output

Then measure between + and - on the output XLR.

Mike

 

[stringmike]

And yes, it’s the D

Hi Mike.
Here’s what I measured:
TP1: 0.122V
TP15: 2.10V
Brown wire: 6.25V
Output xlr: 6.22V

 

[nickcion]

Start by testing without.

test results with Q1 pulled.
input XLR    0.777V
TP1    2.5mV
TP15    139mV
tp17    20mV
brown    nothing?
out    310mV

 

[Echo North]

Hey Guys,

Sorry was out of the country for a week.

We have a new help doc.  Start with this and post back:

http://www.hairballaudio.com/blog/resources/post/fetrack-troubleshooting-guide

Mike

 

[beaustep]

Thank you Mike for the troubleshooting guide! Fantastic. I just read through it to see if my answer was there.

Quick question for you.

I am at the stage where I am adding all of the resistors and at R012, it calls for a 2.2k ohm that is brown brown black red red. I cannot find that color combo anywhere in my kit.

Since I've purchased 2 kits, I looked in the other and do not see it there either.

Is there another color combo that will work? I can't remember which one it was, but I used my meter to test them all and found a few that measure at about 2.35k ohms. The color combo is something like brown brown black yellow red.

Thanks Mike!!

 

[Echo North]

Thank you Mike for the troubleshooting guide! Fantastic. I just read through it to see if my answer was there.

Quick question for you.

I am at the stage where I am adding all of the resistors and at R012, it calls for a 2.2k ohm that is brown brown black red red. I cannot find that color combo anywhere in my kit.

Since I've purchased 2 kits, I looked in the other and do not see it there either.

Is there another color combo that will work? I can't remember which one it was, but I used my meter to test them all and found a few that measure at about 2.35k ohms. The color combo is something like brown brown black yellow red.

Thanks Mike!!

RED-YELLOW-BLACK-BROWN-BROWN is 2.4K.

Is there a 2.4K on that board?

Mike

 

[nickcion]

hey mike!

I had pulled q1 based on bad early tests. and now i have tests with Q1 pulled. but don't know what to make of that in terms of  the new guide.

thanks

input XLR    0.777V
TP1    2.5mV
TP15    139mV
tp17    20mV
brown    nothing?
out    310mV

 

[Echo North]

hey mike!

I had pulled q1 based on bad early tests. and now i have tests with Q1 pulled. but don't know what to make of that in terms of  the new guide.

thanks

input XLR    0.777V
TP1    2.5mV
TP15    139mV
tp17    20mV
brown    nothing?
out    310mV

Hmmmm something is wrong early on.  Is your input transformer and t-pad soldered properly?
All your L brackets in plate?

Mike

 

[nickcion]

Hmmmm something is wrong early on.  Is your input transformer and t-pad soldered properly?
All your L brackets in plate?

Mike

L brackets are all good.. continuity to chassis. transformer is not installed backwards. T-pad looks superb on all 9 pads

 

[Echo North]

L brackets are all good.. continuity to chassis. transformer is not installed backwards. T-pad looks superb on all 9 pads

Under the original test conditions above. What is your AC V between the two outer pins on the primary side and two outer pins on the secondary side of the transformer?

Mike

 

[nickcion]

i feel like my meter doesn't do so hot on the 1 kHz signal if i move my common off chassis?

I have the input 1 khz signal across my primary when i scope the primary and nothing on the secondary.

but the crappy meter is struggling to do much in that same measurement.
Noticing i have some low resistance between TP1 and chassis.

(also noting i have my signal on the output xlr when i scope)

Should i be trying to pull T1 and ohm it out?

 

[Silmica]

Built a Rev D with 1.14 board. But something is not right.

I checked the power supply before continuing on and got the proper voltages on CR8(30vdc) & CR9(-10VDC).

Now that I have continued building the unit and went to calibrate it and I am not getting any voltage out of the output with the .775VAC 1K sine wave on the input. I then checked my CR8 & CR9 again and I get 30.95Vdc on CR8 but 0Vdc on CR9. I poked around with other measurements on various areas of the board and compared to the schematic and got similar results but I am a bit stumped on this one and could used some help. I re-flowed many of the pads on the board just to see if that would do it but nothing.

At TP18 I get 0Vdc no mater where I put R59 at. What would make the voltage go to 0Vdc?

When building it, I double checked every resistor with a multi-meter just to be sure I was putting in the proper resistor in place.

 

[Silmica]

Built a Rev D with 1.14 board. But something is not right.

I checked the power supply before continuing on and got the proper voltages on CR8(30vdc) & CR9(-10VDC).

Now that I have continued building the unit and went to calibrate it and I am not getting any voltage out of the output with the .775VAC 1K sine wave on the input. I then checked my CR8 & CR9 again and I get 30.95Vdc on CR8 but 0Vdc on CR9. I poked around with other measurements on various areas of the board and compared to the schematic and got similar results but I am a bit stumped on this one and could used some help. I re-flowed many of the pads on the board just to see if that would do it but nothing.

At TP18 I get 0Vdc no mater where I put R59 at. What would make the voltage go to 0Vdc?

When building it, I double checked every resistor with a multi-meter just to be sure I was putting in the proper resistor in place.

Well I pulled out the zener diode and measured the resistance both ways and get .2 ohms on either side of it. That does not seem right. I have no clue on what happened here. I will see if I can get another one to try.

 

[Silmica]

Well I pulled out the zener diode and measured the resistance both ways and get .2 ohms on either side of it. That does not seem right. I have no clue on what happened here. I will see if I can get another one to try.

Okay, got a new zener diode from a local electronic store and just tacked it into place (having trouble getting the leads through the holes right now as they are a little thicker than the one that came with the unit).

Now I get -9.88Vdc on the -10 side of the zener diode - Great!

Now trying calibration but now I still get 0vac at the output. I can measure between 0vdc and -2.982vdc at TP18 when I sweep the R59 pot. So that is good it seems.

Now what is next that could be the problem?

 

[Silmica]

Okay, got a new zener diode from a local electronic store and just tacked it into place (having trouble getting the leads through the holes right now as they are a little thicker than the one that came with the unit).

Now I get -9.88Vdc on the -10 side of the zener diode - Great!

Now trying calibration but now I still get 0vac at the output. I can measure between 0vdc and -2.982vdc at TP18 when I sweep the R59 pot. So that is good it seems.

Now what is next that could be the problem?

Well working through this some more (by myself apparently LOL) i found that the signal was only getting to TP1. I found out that if I play with C1 by wiggling it I could get the signal to TP15 and 17 and the output which is good. So I tried various times re-soldering C1 but still have that problem. I'm wondering if my 1uF cap has a intermittent problem within itself. i got the Orange drop upgraded caps. i may just put the 1uF electrolytic in to see if I have any problems with that. i may need to have a new 1uF cap sent to me but I will see.

Now either way when I can the cap to work i can actually calibrate it now which is good but still the C1 is an issue that needs to be resolved.

 

[lunchbox06452]

Hi Hairball team,

Currently am on my second FET/RACK Rev A. everything has gone great with the build and calibration went about the same as my first unit. I am noticing that my second rack is showing that it is much more aggressive with the same compression settings. often reading 5db more reduction then my first unit. So much so when I was using it on a session the input was nearly off in order to not have it drop the needle.

Do we have a recommendation on where I should start. I have got through calibration from top down and even opened up my first unit as reference to make sure I didn't get anything wrong. 

I also thought it could have been a mixed resistor value in the signal preamp or the signal line amp but everything is checking out to spec and each other.
Thank you.

 

[Echo North]

Hi Hairball team,

Currently am on my second FET/RACK Rev A. everything has gone great with the build and calibration went about the same as my first unit. I am noticing that my second rack is showing that it is much more aggressive with the same compression settings. often reading 5db more reduction then my first unit. So much so when I was using it on a session the input was nearly off in order to not have it drop the needle.

Do we have a recommendation on where I should start. I have got through calibration from top down and even opened up my first unit as reference to make sure I didn't get anything wrong. 

I also thought it could have been a mixed resistor value in the signal preamp or the signal line amp but everything is checking out to spec and each other.
Thank you.

Could be the t-pad itself, they have tolerances. Also make sure it's mounted so the line is in the same spot FCW. Are both T-pads grey?

Start by going through here:
http://www.hairballaudio.com/blog/resources/post/fetrack-troubleshooting-guide

Particularly the Pad 22/21/CR stuff.

Mike

 

[Echo North]

i feel like my meter doesn't do so hot on the 1 kHz signal if i move my common off chassis?

I have the input 1 khz signal across my primary when i scope the primary and nothing on the secondary.

but the crappy meter is struggling to do much in that same measurement.
Noticing i have some low resistance between TP1 and chassis.

(also noting i have my signal on the output xlr when i scope)

Should i be trying to pull T1 and ohm it out?

TP1 low resistance is normal.  What is it?  Something like 16Ω (I can't remember exactly).

Which pins on T1 are shorted to the can of T1 (using your Ω meter)?

Mike