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

[Echo North]

OLΩ nothing...

Unplug the transformer and the 3 pin from the V select PCB.  What is your DC Ω between pin 1 and pin 5 (where white and blue would be) and Pin 3 and Pin 7 where (where black and red would be).

Make sure your switch is on 115V.

Unplugged.

 

[lackstudios]

Unplug the transformer and the 3 pin from the V select PCB.  What is your DC Ω between pin 1 and pin 5 (where white and blue would be) and Pin 3 and Pin 7 where (where black and red would be).

Make sure your switch is on 115V.

Unplugged.

1 & 5 .2Ω
3 & 7 .2Ω

 

[Echo North]

1 & 5 .2Ω
3 & 7 .2Ω

Cool.

Now check between Pin 1 on the seven pin and pin 1 on the three pin connector above it. What do you get for DC Ω?

Then check between Pin 3 on the seven pin and pin 3 on the three pin connector above it. What do you get for DC Ω?

 

[lackstudios]

Cool.

Now check between Pin 1 on the seven pin and pin 1 on the three pin connector above it. What do you get for DC Ω?

Then check between Pin 3 on the seven pin and pin 3 on the three pin connector above it. What do you get for DC Ω?

Pin 1 on the seven pin and pin 1 on the three pin connector .1Ω
Pin 3 on the seven pin and pin 3 on the three pin connector .1Ω

 

[Echo North]

Pin 1 on the seven pin and pin 1 on the three pin connector .1Ω
Pin 3 on the seven pin and pin 3 on the three pin connector .1Ω

I'm stumped.

Having OLΩ on the outer pins of the three pin connector, would indicate that both your primary windings are broken. We've have yet to have a defective transformer. I also tested the second one I sent you and both were tested by the manufacturer.

I can't imagine anything you could be doing to damage them, that's what the fuse is there for.

You'll have to send them back for testing, email me.

Mike

 

[lackstudios]

I'm stumped.

Having OLΩ on the outer pins of the three pin connector, would indicate that both your primary windings are broken. We've have yet to have a defective transformer. I also tested the second one I sent you and both were tested by the manufacturer.

I can't imagine anything you could be doing to damage them, that's what the fuse is there for.

You'll have to send them back for testing, email me.

Mike

Hold up!!!!!! 

I switched back to the old transformer and now I'm getting all the correct readings...

around 100Ω on the BLK/WHT and BLU/RED...

now 52.8Ω on the outer 2 pins of the 3 connector...

I'm not sure if I am testing wrong, I have a Fluke 117...

 

[Echo North]

Hold up!!!!!! 

I switched back to the old transformer and now I'm getting all the correct readings...

around 100Ω on the BLK/WHT and BLU/RED...

now 52.8Ω on the outer 2 pins of the 3 connector...

I'm not sure if I am testing wrong, I have a Fluke 117...

You must have a shady solder joint somewhere.  You might want to reflow everything. Your readings are good though.

 

[lackstudios]

You must have a shady solder joint somewhere.  You might want to reflow everything. Your readings are good though.

ok, on which PCB?

 

[Echo North]

ok, on which PCB?

No idea. You're just getting weird inconsistent readings.

There is a bad connection somewhere. This old transformer had OL secondaries before, but now in parallel on the switch you're getting 52Ω which would indicate that they are both ok now.

How are you voltages? Working now?

 

[lackstudios]

No idea. You're just getting weird inconsistent readings.

There is a bad connection somewhere. This old transformer had OL secondaries before, but now in parallel on the switch you're getting 52Ω which would indicate that they are both ok now.

How are you voltages? Working now?

yeah, sorry about that...been using a mutimeter a long time... :-/ not sure whats going on......

so, I'm getting 3.4 VAC on the orange secondary (next to black) and 4.0 VAC on the orange secondary (next to white)
this is with the unit powered on and my black DDM lead in the chassis screw hole...
the secondary connector is unplugged from the main PBC and probing the red DMM lead in each orange connector...

 

[Echo North]

yeah, sorry about that...been using a mutimeter a long time... :-/ not sure whats going on......

so, I'm getting 3.4 VAC on the orange secondary (next to black) and 4.0 VAC on the orange secondary (next to white)
this is with the unit powered on and my black DDM lead in the chassis screw hole...
the secondary connector is unplugged from the main PBC and probing the red DMM lead in each orange connector...

You sure you're measuring AC V and not AC mA or something?

Measure you primary. With the unit on and everything in place....BE CAREFUL....measure the two tabs on the V select PCB left side.  I'm talking about the 6 tabs between the 7 and 3 pin connector.  The two on the left. What does the top one read in AC referencing the chassis, and what does the bottom on read?

Also confirm your ground lug is solidly in place, and all three of your main PCB L brackets are solidly in place.

Mike

 

[lackstudios]

You sure you're measuring AC V and not AC mA or something?

Measure you primary. With the unit on and everything in place....BE CAREFUL....measure the two tabs on the V select PCB left side.  I'm talking about the 6 tabs between the 7 and 3 pin connector.  The two on the left. What does the top one read in AC referencing the chassis, and what does the bottom on read?

Also confirm your ground lug is solidly in place, and all three of your main PCB L brackets are solidly in place.

Mike

ok, Top left 43.8 VAC
bottom 55.8 VAC

 

[Echo North]

ok, Top left 43.8 VAC
bottom 55.8 VAC

Wow. Ya that's crazy.

You have all the L brackets in place? They provide grounding to the chassis, not just structural support.

And both transformers behave differently?

You may just have to send the whole thing in. None of this adds up.

Mike

 

[lackstudios]

ok, Top left 43.8 VAC
bottom 55.8 VAC

OK, I'm having a twighlight zone moment...I SWEAR I checked the DC voltage 1,000 times on CR8!!!!
Now I'm getting the correct readings....30v and -10v
I am completely stumped and happy at the same time!

Sorry to waste your precious time!

 

[Echo North]

OK, I'm having a twighlight zone moment...I SWEAR I checked the DC voltage 1,000 times on CR8!!!!
Now I'm getting the correct readings....30v and -10v
I am completely stumped and happy at the same time!

Sorry to waste your precious time!

Glad it's sorted.

Please send back one of the transformers with the return label I send.  Whoop! Weekend!

 

[lackstudios]

Glad it's sorted.

Please send back one of the transformers with the return label I send.  Whoop! Weekend!

Yes, of coarse...have a great weekend!

 

[Diamondj421]

Somehow, I reconnected everything and have made it through the first two steps of calibration. Now, on step 3, I can't seem to get the input pot to reach 2.44VAC at the output. I'm maxing out at 2.09VAC. Would this be caused by the ghetto rigging that just took place on Q9,10,12 and 13? I'm getting real close to just sending this in but would feel so much better if I could at least get through one of these beasts!

 

[lackstudios]

Hey there...ALL the way to the last step and DANG! everything was going smooth until I got to:

"Set your DMM to measure DC volts and set it to measure the DC volts across TP10 and TP11 for the Rev A and accross R74 for the Rev D.

Zero the compressors "GR" meter with the R71 zero adjust pot on the front panel.
Adjust pot R75 (null adjust)  for 0.0 Volts across TP10/TP11 (Rev A) or R74 (Rev D).
Repeat 1 & 2 until both conditions are met."

I got 0.00 DCV between TP10/TP11, but my R71 adjust pot wont budge the GR meter...

 

[Echo North]

Hey there...ALL the way to the last step and DANG! everything was going smooth until I got to:

"Set your DMM to measure DC volts and set it to measure the DC volts across TP10 and TP11 for the Rev A and accross R74 for the Rev D.

Zero the compressors "GR" meter with the R71 zero adjust pot on the front panel.
Adjust pot R75 (null adjust)  for 0.0 Volts across TP10/TP11 (Rev A) or R74 (Rev D).
Repeat 1 & 2 until both conditions are met."

I got 0.00 DCV between TP10/TP11, but my R71 adjust pot wont budge the GR meter...

Does the null adjust change the DC voltage?

You'll need to go through the values in the GR meter amp section, only a few parts, confirm them and reflow ant suspect joints.

Mike

 

[Echo North]

Somehow, I reconnected everything and have made it through the first two steps of calibration. Now, on step 3, I can't seem to get the input pot to reach 2.44VAC at the output. I'm maxing out at 2.09VAC. Would this be caused by the ghetto rigging that just took place on Q9,10,12 and 13? I'm getting real close to just sending this in but would feel so much better if I could at least get through one of these beasts!

Are you sure your in GR OFF mode?