I just purchased a used XF6.  On power up, when the audio engine starts there is a bit of a pulse sound on the main outs.  If I power it down with the monitors on, there is a HUGE percussive pulse.  I had a XS6 before, and I don’t recall it behaving this way.

Do you know if the previous owner gigged with the XF6? The output muting transistors can be damaged if the line outputs were connected to a mixer that had phantom power turned on.

Do you have access to, and know how to use, a DC voltmeter?

Yes, I have a voltmeter.

playstation - 27 January 2017 12:24 AM

Yes, I have a voltmeter.

OK. Plug a TS cable into each of the line outputs, L/MONO, R, and the two ASSIGNABLE, L and R. Check for DC voltage at the unconnected end of each cable, from Tip to Sleeve. When things are normal the voltage will be quite low (typically very close to zero), and no higher than about 50 millivolts (0.050 volts). When the muting transistor at an output is leaky, the voltage is often several tenths of a volt, and can be as high as a few volts.

Leaky muting transistors cause more than pops when powering up and down, they also can cause distortion and crosstalk between channels.

Most of the time, in my experience, even if the line outputs have a problem, the headphone output won’t have damaged muting transistors. If you verify the problem, but need to use the XF before it’s fixed, you can use the headphone output with a cable that breaks out the TRS connection to two TS type.

I have around 2.5 volts on them. So, I found another thread and I guess I need to get that JA board - WU494900.

playstation - 27 January 2017 02:15 AM

I have around 2.5 volts on them.

That voltage certainly confirms the cause of what you’re experiencing.

 

playstation -

So, I found another thread and I guess I need to get that JA board - WU494900.

I’ve posted about leaky muting transistors in several threads, and a member provided the part number for the XF board in one of those threads. The individual muting transistors can be replaced by someone familiar with surface-mount component repair. However, service charges for that could be more than the cost of the entire jack board, so buying one might be the better alternative.

Thanks for the help!

playstation - 27 January 2017 11:10 AM

Thanks for the help!

You’re welcome. I hope the repair goes smoothly.

Update:  Repair complete and it fixed the problem!  Woohoo! 

Some pics of the JA board swap: outJA board

JA board out

Click thumbnail to see full-size image

playstation - 04 February 2017 02:17 PM

Update:  Repair complete and it fixed the problem!  Woohoo!

Congrats!

Just make sure to never connect the XF’s outputs to any mixer inputs having phantom power turned on - or you might need to change the jack board again.  :-(

5pinDIN - 04 February 2017 03:42 PM

playstation - 04 February 2017 02:17 PM

Update:  Repair complete and it fixed the problem!  Woohoo!

Congrats!

Just make sure to never connect the XF’s outputs to any mixer inputs having phantom power turned on - or you might need to change the jack board again.  :-(

5pinDIN, this only applies to the assignable outputs correct?
Not the main L and R ?

Stashman - 04 February 2017 06:50 PM

5pinDIN - 04 February 2017 03:42 PM

playstation - 04 February 2017 02:17 PM

Update:  Repair complete and it fixed the problem!  Woohoo!

Congrats!

Just make sure to never connect the XF’s outputs to any mixer inputs having phantom power turned on - or you might need to change the jack board again.  :-(

5pinDIN, this only applies to the assignable outputs correct?
Not the main L and R ?

All of the outputs - L/MONO, R, ASSIGNABLE, and even PHONES - have muting transistors, and are susceptible to damage from being connected to phantom power. Common phantom power voltages are 12, 24, and 48 volts, although there are some others in between. The higher the voltage, the more likely to cause problems. Since it may not be possible to know what the voltage level is, try to be certain that phantom power is not turned on.

It’s also a good idea to try to avoid electrostatic discharge - for example, don’t walk across the studio carpet and then touch a connected audio cable without discharging yourself to ground first.

Thanks for the clarification and the possible problems from electrostatic discharge.
I’m definetly going to check outputs when I get home.
The same measurements apply for checking audio L and R outputs too?

Stashman - 04 February 2017 09:11 PM

Thanks for the clarification and the possible problems from electrostatic discharge.
I’m definetly going to check outputs when I get home.
The same measurements apply for checking audio L and R outputs too?

You’re welcome. Yes, there should be no or very low DC voltage on
all audio outputs. See my second post in this thread.

I wrote this article to tell my personal experience about this breakdown that I also met with the First Motif.

http://keyboardwaves.com/repair-motif-line-output/

You can fix it for less than $ 10

Click thumbnail to see full-size image