F'd up MPC3000...headphone jack actin up

I get a whole bunch of different noises out of my 3K on stereo outs and mainly the headphone jack.
If i turn off the LCD backlight that takes care of some of it.
Turning of SCSI to my CF reader doesnt do anything, but i can hear it make noise while its loading or saving.
There is always a constant high pitched whine and the weirdest thing of all is if i plug in headphones i cant play sequences, they stop after several ticks, and usually the tempo gets changed to mad slow. WTF how can headphones **** with the actual computer? some kinda interference?
anyone know whats goin on?
chris

Subby32 wrote:I get a whole bunch of different noises out of my 3K on stereo outs and mainly the headphone jack.

The head phone jack is often quite noisy on these machines as a result of how the grounding system is set up.

Subby32 wrote:If i turn off the LCD backlight that takes care of some of it.
Turning of SCSI to my CF reader doesnt do anything, but i can hear it make noise while its loading or saving.

You have a grounding fault some where in your system by the sounds of it.

Subby32 wrote:There is always a constant high pitched whine and the weirdest thing of all is if i plug in headphones i cant play sequences, they stop after several ticks, and usually the tempo gets changed to mad slow. WTF how can headphones **** with the actual computer? some kinda interference?
anyone know whats goin on?
chris

MPC3000 machines MUST be run grounded.

What you are describing sounds reads like symptoms of a grounding fault.

Either in the machine or as a result of a incorrectly earthed mains distribution / MPC3000 / other connected devices.

Similar weirdness has been observed with grounding issues where internal card readers are concerned.

viewtopic.php?f=4&t=113476&hilit=earth+ground

Is your MPC3000 connected directly to the mains power outlet ?

Is the mains power outlet earthed correctly ?

Or ...

Via a step down / step up converter ?

If it's connected via a step down / step up converter then is it an un-earthed switch mode type ? Or is it a good old linear chunky transformer type ?

Do you have a multi meter with continuity checking capability and an ability to use it

I can guide you through some trouble shooting steps if you have the above and are capable in this regard.

Rohan.

Interesting. I have a whine in my mpc3k headphone jack as well. Not the stereo outs. I never use headphones so I said fuggit, but I'd hate grounding issues to cause future problems.

What do you think? Is it OK to leave be for now?

lifesabatch wrote:Interesting. I have a whine in my mpc3k headphone jack as well. Not the stereo outs. I never use headphones so I said fuggit, but I'd hate grounding issues to cause future problems.

What do you think? Is it OK to leave be for now?

Ideally, you want everything grounded as best as it can, so in the case of ESD or some kind of static discharge, the zap will go via the past of least resistance (the grounded path) instead of going through the circuitry and potentially frying something inside. Static shocks can have in excess of 2000V in them....

If your headphone jack isn't grounded, you may just need to make sure the ground path of the headphone jack is making contact with something else that's grounded in the MPC -- usually the chassis. You can verify this with a multimeter too as Rohan suggested.

lifesabatch wrote:Interesting. I have a whine in my mpc3k headphone jack as well. Not the stereo outs. I never use headphones so I said fuggit, but I'd hate grounding issues to cause future problems.

What do you think? Is it OK to leave be for now?

A whine out of the head phone jack alone is normal behavior.

When the whine appears in the other outputs or on the record inputs then there is an issue.

Now ... to a quick chassis ground check method.

Power off.

Disconnect all audio cables from the MPC3000

Disconnect the IEC mains power from the MPC3000.

Set your multi meter to continuity ( beeper ) mode.

Touch one probe to the MPC3000 power IEC earth pin ( the center lower one ).

Touch the other pin to the SCSI port outer metal jacket. ( or VGA port outer metal jacket )

Beep ? Internal mains earth intact.

No beep ? Internal mains earth open.

If you have a "non contact" voltage meter.

Plug the MPC3000 back into the mains power.

Switch on the MPC3000.

Run the "non contact" sensor over the front panel.

If it lights up ? You have a mains grounding problem.

If it doesn't ? You might not have a mains grounding problem.

Any further testing of correct continuity for ground paths will require the MPC3000 to be opened and further probed by a tech who is experienced on working with these sort of issues.

For the original thread poster, "Subby32" ...

Please answer these questions from my initial response:

Is your MPC3000 connected directly to the mains power outlet ?

Is the mains power outlet earthed correctly ?

Or ...

Via a step down / step up converter ?

If it's connected via a step down / step up converter then is it an un-earthed switch mode type ? Or is it a good old linear chunky transformer type ?

Rohan.

Its plugged straight into the power outlet, and the cable is grounded.
My dad's got a multimeter so when i get a chance i'll have him check it out
and try the steps u posted above
thanks

BUMPITY BUMP BUMP!!!!!!!!!!!!!

YOOOOOOOOO I FIXED IT

I been having that same loud ass noise comin from the headphone jack for the past year and it pissed me off. A few months ago I called Bruce Forat out cali. about this and he said some times the four bolts under the floppy/card reader need to be tighten SUPER TIGHT because it acts as a ground. I thought i checked it out but i guess i didnt take him serious. So tonight i was reading this thread and i went at it one more time. It turns out that there is some type of plate directly under my card reader that has its own set of four bolts. I remembered at one time I did take it off to see what it looked like but i guess i didnt tighten it tight enough .So i pulled out the screw driver and tightend the hell out of it and I was mising a bolt for my card reader. I tightened all theses bolts as far as they would go!!(and I mean super tight!!) Plugged my headphones in the headphone jack b4 i turned on the mpc and BAM!! NO MORE NOISE OUT OF THE HEAD PHONE JACK!!! I CANT STOP JUMPNIN UP AND DOWN!!!!!! AGGGHHHHH! WOOOOOO!

DJ Supreme wrote:BUMPITY BUMP BUMP!!!!!!!!!!!!!

YOOOOOOOOO I FIXED IT

I been having that same loud ass noise comin from the headphone jack for the past year and it pissed me off. A few months ago I called Bruce Forat out cali. about this and he said some times the four bolts under the floppy/card reader need to be tighten SUPER TIGHT because it acts as a ground. I thought i checked it out but i guess i didnt take him serious. So tonight i was reading this thread and i went at it one more time. It turns out that there is some type of plate directly under my card reader that has its own set of four bolts. I remembered at one time I did take it off to see what it looked like but i guess i didnt tighten it tight enough .So i pulled out the screw driver and tightend the hell out of it and I was mising a bolt for my card reader. I tightened all theses bolts as far as they would go!!(and I mean super tight!!) Plugged my headphones in the headphone jack b4 i turned on the mpc and BAM!! NO MORE NOISE OUT OF THE HEAD PHONE JACK!!! I CANT STOP JUMPNIN UP AND DOWN!!!!!! AGGGHHHHH! WOOOOOO!

I tried this last night. I was getting a high pitch noise from the headphone jack. I tightened the floppy drive screws at the bottom of the MPC and no more noise. What a weird fix but it worked . Since joining this forum, the info here has been so helpful. Thanks Everyone!!!!

wow

my first 3000 had this and it really pissed me off. It was one of the various reasons I sold it.
Good thing to know now.

.toon

tight ass thread! :praise:

yes! great thread, to the dude who started it, please take the honor of transferring this info to the bible up above

Subby32 wrote:I get a whole bunch of different noises out of my 3K on stereo outs and mainly the headphone jack.
If i turn off the LCD backlight that takes care of some of it.
Turning of SCSI to my CF reader doesnt do anything, but i can hear it make noise while its loading or saving.
There is always a constant high pitched whine and the weirdest thing of all is if i plug in headphones i cant play sequences, they stop after several ticks, and usually the tempo gets changed to mad slow. WTF how can headphones **** with the actual computer? some kinda interference?
anyone know whats goin on?
chris

Did you try tighten the floppy screw at the bottom?..i mean you have to make them super tight. This fixed the headphone noise i had. Combined with the info for grounding might solve the issue.