Old Motifator threads are available in the Archive.
playstation
Total Posts: 17
Joined 07-18-2008 status: Regular |
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. |
5pinDIN
Total Posts: 11891
Joined 09-16-2010 status: Legend |
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? |
playstation
Total Posts: 17
Joined 07-18-2008 status: Regular |
Yes, I have a voltmeter. |
5pinDIN
Total Posts: 11891
Joined 09-16-2010 status: Legend |
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. |
playstation
Total Posts: 17
Joined 07-18-2008 status: Regular |
I have around 2.5 volts on them. So, I found another thread and I guess I need to get that JA board - WU494900. |
5pinDIN
Total Posts: 11891
Joined 09-16-2010 status: Legend |
That voltage certainly confirms the cause of what you’re experiencing.
Â
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. |
playstation
Total Posts: 17
Joined 07-18-2008 status: Regular |
Thanks for the help! |
5pinDIN
Total Posts: 11891
Joined 09-16-2010 status: Legend |
You’re welcome. I hope the repair goes smoothly. |
playstation
Total Posts: 17
Joined 07-18-2008 status: Regular |
Update: Repair complete and it fixed the problem! Woohoo! Some pics of the JA board swap: outJA board Image Attachments
|
5pinDIN
Total Posts: 11891
Joined 09-16-2010 status: Legend |
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. Â :-( |
Stashman
Total Posts: 79
Joined 08-24-2014 status: Experienced |
5pinDIN, this only applies to the assignable outputs correct?
|
5pinDIN
Total Posts: 11891
Joined 09-16-2010 status: Legend |
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. |
Stashman
Total Posts: 79
Joined 08-24-2014 status: Experienced |
Thanks for the clarification and the possible problems from electrostatic discharge.
|
5pinDIN
Total Posts: 11891
Joined 09-16-2010 status: Legend |
You’re welcome. Yes, there should be no or very low DC voltage on
|
stefpiano
Total Posts: 15
Joined 08-29-2012 status: Regular |
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 Image Attachments
|