Technical questions for the MPC2000xl and the MPC2000
By C_murder Sat Jul 20, 2019 4:31 pm
I picked up a used 2kxl with the 8 output board. The board is being seen by the OS but no audio. When the channel signal is turned up I can here the mono sample but it's garbled and distorted. I looked around on this forum and everyone is talked about installing the expansion wrong or if it's a mutecs. This is an akai expansion board and the R2 resistor is still metering continuity. I have loads of experience fixing vintage gear so has anyone experienced something like this or knows of a service manual for reference of what voltages and resistances that should be happening. It's my bet it's ic501 or ic525 on the fritz. Both fuses on the board are also metering continuity so any help would be greatly appreciated. Thanks!
By C_murder Tue Jul 30, 2019 11:33 pm
Yes, I have those but was looking for a better service manual for the 8 output board. Doesn't seem to be to much info on just that. I put in new digital to analog converters IC's as those were socketed and easy to switch to no avail. Im starting to think I need to probe the IC's with a logic tester. If anyone else has any input would like to hear it. Will keep this updated as someone in the future may face a similar issue.
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By Phonetic Mon Aug 05, 2019 3:30 pm
Any word on this? I have an 8 out (Mutec) board & can't get any sound out of it. The MPC recognizes it but no output.
Sounds a very similar problem to the OP
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By Phonetic Wed Aug 07, 2019 8:19 am
C_murder wrote:I have a new op amp on the way will let you know when I solder it in. Fingers crossed


Sweet man, please do. Would love to finally get this sorted
By C_murder Mon Aug 12, 2019 12:57 pm
So I replaced the op amp on the 8 output board this weekend and there was no change. The audio is still distorted and underpowered. I have a logic probe on the way to see if I figure out which ic is acting up.
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By Phonetic Tue Aug 27, 2019 2:17 pm
C_murder wrote:So I replaced the op amp on the 8 output board this weekend and there was no change. The audio is still distorted and underpowered. I have a logic probe on the way to see if I figure out which ic is acting up.


Any joy with this yet? Don't mean to rush you of course...
Would really love to get mine done & any advice would be well appreciated cos I'm stumped with the thing!
By C_murder Fri Sep 06, 2019 7:12 pm
Ok, so here's what I did to fix the board. I went through and checked all the IC's and we're getting all weird readings, nothing was right. I started to meter the voltages on the board and went to check the 5v regulator and there it was. It was putting out a 3.2v reading which was throwing all the chips out of wack. Apparently these 4085 regulators are well know to over heat and send various voltages. I fixed a older rack effects unit the same week and it was literally the same regulator that was shot. It will meter continuity but those voltages weren't 5v. Check that and if it's off just replace it.
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By Phonetic Wed Sep 11, 2019 12:14 pm
C_murder wrote:Ok, so here's what I did to fix the board. I went through and checked all the IC's and we're getting all weird readings, nothing was right. I started to meter the voltages on the board and went to check the 5v regulator and there it was. It was putting out a 3.2v reading which was throwing all the chips out of wack. Apparently these 4085 regulators are well know to over heat and send various voltages. I fixed a older rack effects unit the same week and it was literally the same regulator that was shot. It will meter continuity but those voltages weren't 5v. Check that and if it's off just replace it.


Ah ok, thanks for posting your results. Glad to know it can be fixed.
Better get the ol' multimeter out :)