Share your knowledge on these two classic MPCs
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By Dan Clark Wed Jun 02, 2010 1:44 am
Hi there,

My 3000 has stopped outputting any sound. I opened it up to see if something had come loose but couldn't find anything obvious , switched it back on and it worked, until i powered it up again. Now there's no sound at all. Samples are loading, everything seems fine except there's no sound.

Has anybody experienced the same thing or something like it?

Thanks for any help

Dan
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By Dan Clark Wed Jun 02, 2010 2:30 am
Thanks for reply mr_debauch :D

It's the same from the headphones. I can hear the hiss of the amp, from both the headphone and the main out...... ah i just tried the other "outs" 1/2 and 3/4 there working!!

So the headphone and main out are not working, yet i can hear the hiss from them as i turn it up.
By mpc3000le Thu Jun 03, 2010 10:51 am
Dan Clark wrote:Has anybody experienced the same thing or something like it?
Thanks for any help
Dan


Yes ... sadly...

This happened to my own machine recently.

A fault of the power on mute circuit that resets:

1: the MAIN L/R output relay.
2: the pre DAC digital filter IC.

Open the machine and look at the relay on the main output board. ( The top one )

Switch it on and observe if it changes state visually. ( if its switching mechanism moves )

If not then the power on relay enable system is faulting.

Apart from checking power supply voltages and such...

Its likely that the following will need checking and possible addressing by way of replacement where necessary if faulty: ( maybe a job for a repair technician if you're not up for the task )

Part Location: -- Part type:

RL101 ----------- G5A2337P RELAY
TR101 ----------- 2SC391B TRANSISTOR
D101 ------------ DS135 DIODE
IC107 ----------- M51955BL VOLTAGE RESET IC
R144 ------------ 7.5K RESISTOR
R145 ------------ 1K RESISTOR
R146 ------------ 4.7K RESISTOR
C189 ------------ 10uF/25v ELECTROLYTIC CAPACITOR
C218 ------------ 0.1uF

In my own case, IC107, TR101, RL101 and C189 got things going again when changed over.

Hope this helps.

Rohan
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By Dan Clark Sun Jun 13, 2010 7:08 am
Thanks for the comprehensive reply Rohan. Really great help. I'll check out the main output board. Do you have any recommendations of places to get parts if needed? Also are these parts MPC 3000 specific?

Thanks again :)

Dan
By jimmie Wed Jun 19, 2013 5:57 pm
My mpc 3000 has the same issue now.
There is no sight or sound of the relay switching on any more when I turn the machine on.

The stereo outs are silent.
The individual outs and headphone out emit a nasty tone.
The machine still functions in all other respects.

The above diagnosis by Rohan seems to fit well.


Does anybody have any idea where I can find the following parts:

RL101 ----------- G5A237P RELAY
TR101 ----------- 2SC391B TRANSISTOR
IC107 ----------- M51955BL VOLTAGE RESET IC

??

or know what the current-day equivalents are?

Cheers
By MPCHunter Wed Jun 19, 2013 10:19 pm
jimmie wrote:
Does anybody have any idea where I can find the following parts:

RL101 ----------- G5A237P RELAY
TR101 ----------- 2SC391B TRANSISTOR
IC107 ----------- M51955BL VOLTAGE RESET IC

??

or know what the current-day equivalents are?



TR101 2SC391B -- modern part NTE319P (eBay, mouser, etc)
RL101 G5A237P -- discontinued (ebay, you probably want a 12V version)
IC107 M51955BL -- discontinued M51955B (utsource, the L in the part number is redundant )
By jimmie Thu Jul 04, 2013 1:55 pm
MPCHunter wrote:TR101 2SC391B -- modern part NTE319P (eBay, mouser, etc)
RL101 G5A237P -- discontinued (ebay, you probably want a 12V version)
IC107 M51955BL -- discontinued M51955B (utsource, the L in the part number is redundant )


Cheers for that.

I managed to get a G5A237P relay and fitted it.
The problem remained.

It turns out that I needed to change the capacitor prior to the relay.
Been working for that last two weeks now :)