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

[Echo North]

So I have the DMM set to the 2V setting and pad 18 is reading 0 to -.092 and pad 7 is reading 0 to -.089.  Am I still far off?  Where is the power supply test point? This is all new to me. My Lola build was assemble and record.

Your pad 18 is all messed up. It's too low. should be 0 to about -2.5 VDC.

Check the value of R35 (10K) and R60 (3.9K). Are they the right value? Re-flow those joints.

What is your DCV on each side of R35 and then each side of R60. Always using chassis for common.

Mike

 

[Echo North]

I think he's talking about the Diode CR9, turn your unit on and measure it in DC and see if you get -10VDC./

Check the build guide and scroll down to the bottom to see how to test it

Link: http://www.hairballaudio.com/blog/resources/build-guides/fetrack-v2-build-and-calibration-guide

Wait for Mikes response though, that might not be it. Just tryin to help!

Good Luck

Yes also check your -10V test point as described in the guide.

 

[Diamondj421]

Your pad 18 is all messed up. It's too low. should be 0 to about -2.5 VDC.

Check the value of R35 (10K) and R60 (3.9K). Are they the right value? Re-flow those joints.

What is your DCV on each side of R35 and then each side of R60. Always using chassis for common.

Mike

Remounted R35 and R60.  R35 is reading -9.85V and -0.0V. R60 is reading -0.0V and -.08V. I assumed that my meter was just a little off at the power supply test point but should it be exactly 10V or should I be rounding up as I have been from -9.85V?

 

[Echo North]

Remounted R35 and R60.  R35 is reading -9.85V and -0.0V. R60 is reading -0.0V and -.08V. I assumed that my meter was just a little off at the power supply test point but should it be exactly 10V or should I be rounding up as I have been from -9.85V?

Your problem is around R35. You should have the -9.85(ish) on one side and something around -2.5 on the other. I doubt the resistor is dead, that rarely happens, but who knows. Look for a dead pad on R35. Measure it's resistance in place...what do you get. It may not read 10K and that's fine...just tell me what you get.

Mike

 

[Diamondj421]

Your problem is around R35. You should have the -9.85(ish) on one side and something around -2.5 on the other. I doubt the resistor is dead, that rarely happens, but who knows. Look for a dead pad on R35. Measure it's resistance in place...what do you get. It may not read 10K and that's fine...just tell me what you get.

Mike

It's reading -39.1K

 

[Echo North]

It's reading -39.1K

Resistance is not a (-) value. You just measure the resistance across the resistor. A lead on each leg with the meter set to ohms. You should probably be getting between 1-2KΩ.

Mike

 

[Diamondj421]

Resistance is not a (-) value. You just measure the resistance across the resistor. A lead on each leg with the meter set to ohms. You should probably be getting between 1-2KΩ.

Mike

It's still reading at 39,1  I'm going to check all of my components again and I'll get back to you.

 

[ebenchristensen]

I'm a new user to the forum- so I am unsure of the general protocol for throwing a hail mary.

After purchasing the Hairball 1176 rev A, and building it, I have run into a strange issue. After a clean (o what I would describe as a clean) build over the last week, I reached the point of first power on. After running all tests according to the build guides, the VU meter lit up, and with GR engaged pin to the right. After 10 minutes, the need began to slowly fall, and the light would no longer remain lit. Now there is nothing registering on the VU meter.

Are there specific areas/readings I should be looking for along the various test points? I scoured what I could from the forums, but all I can find is a spread sheet that asks me to measure the pins for all of the diodes.

While I am not new to building electronics, this is my first large scale project aside from amps and pedals. Any assistance would be appreciated!

 

[Echo North]

I'm a new user to the forum- so I am unsure of the general protocol for throwing a hail mary.

After purchasing the Hairball 1176 rev A, and building it, I have run into a strange issue. After a clean (o what I would describe as a clean) build over the last week, I reached the point of first power on. After running all tests according to the build guides, the VU meter lit up, and with GR engaged pin to the right. After 10 minutes, the need began to slowly fall, and the light would no longer remain lit. Now there is nothing registering on the VU meter.

Are there specific areas/readings I should be looking for along the various test points? I scoured what I could from the forums, but all I can find is a spread sheet that asks me to measure the pins for all of the diodes.

While I am not new to building electronics, this is my first large scale project aside from amps and pedals. Any assistance would be appreciated!

Hi...you're following the right protocol.

Did your fuse blow?

If you power up the unit and test the +30VDC and -10VDC rail as described in the guide, what do you get?

Mike

 

[Diamondj421]

It's still reading at 39,1  I'm going to check all of my components again and I'll get back to you.

For some stupid reason, R63 had a  270K resistor instead of 1.5K. Replaced it and bam! Step 1 done. The rest are pretty tricky. I doubt you've heard the last from me. Hahaha. Thanks Mike for all of your help!

 

[Diamondj421]

Actually here's a quick question. I misread C2 and C13 and had them mixed up. While removing the cap that was 27pF it broke. I ordered one on Amazon. It doesn't look the same but it's 27pF/50V. Is that ok?

 

[Echo North]

Actually here's a quick question. I misread C2 and C13 and had them mixed up. While removing the cap that was 27pF it broke. I ordered one on Amazon. It doesn't look the same but it's 27pF/50V. Is that ok?

Yup.

 

[Diamondj421]

Anddddddd sure enough... The lowest I can get the VDC across R74 is .31. Any suggestions on this one?

 

[Echo North]

Anddddddd sure enough... The lowest I can get the VDC across R74 is .31. Any suggestions on this one?

Start by going through all of your component values in the meter section and touching up and suspect soldering.

 

[Diamondj421]

Start by going through all of your component values in the meter section and touching up and suspect soldering.

 

[Diamondj421]

I've checked and resoldered. I feel like the more I work on it the worse it's getting though. Do you see any spot I should be concerned about?

 

[Diamondj421]

I've checked and resoldered. I feel like the more I work on it the worse it's getting though. Do you see any spot I should be concerned about?

Bueller...? Bueller...? My soldering is... Anyone? Anyone?

 

[Diamondj421]

New idea. Can someone PLEASE post a picture of a fully functional Rev D PCB that I may compare to. I had some left over resistors that I had to install from the interactive map. I'd just like to see if I possibly have an extra resistor somewhere or not. Can't find a pic of the new Rev D anywhere though. Thanks.

 

[StudioJakubka]

Your problem is around R35. You should have the -9.85(ish) on one side and something around -2.5 on the other. I doubt the resistor is dead, that rarely happens, but who knows. Look for a dead pad on R35. Measure it's resistance in place...what do you get. It may not read 10K and that's fine...just tell me what you get.

Mike

Hi Mike, -9.85VDC and -2.5VDC on R35, rev A? I am way off then.
Is there anywhere Rev A typical voltages? Or voltages on measuring points on the new PCB?
Thanks.

 

[Echo North]

Hi Mike, -9.85VDC and -2.5VDC on R35, rev A? I am way off then.
Is there anywhere Rev A typical voltages? Or voltages on measuring points on the new PCB?
Thanks.

Wait you have a Rev A? Is it the new version that just came out? PCB is V1.12?

What is your DC at pad 18 again?

Mike