Rane MP 24 User Manual

MP 24 SERVICE INFORMATION

CHANGING INTERNAL JUMPER BLOCKS

There exists several programmable options built into the
MP 24. All are located on the Main Board which is the top­most PCB. Access is gained by removing the seven (7) screws
from the top cover. See the main board assembly diagram on
page Schematic-2. Dots on the circuit board indicate jumper
positions as shipped from the factory. To change: pull the
jumper block straight up, move over one pin and push back
down. That's all there is to it.

ZONE OUTPUT JUMPERS

The Zone Outputs are shipped from the factory to include
the output of the Program Equalizer and the Mic signals.
Moving jumpers J18 and J19 to BYPASS changes the Zone
Output to pre-EQ, with no mic signals. Locate J18 and J19
behind the R81 BASS pot on the main circuit board.

TAPE OUTPUT JUMPERS

The Tape Outputs are shipped from the factory to not
include any Mic signal. Moving jumpers J25 and J26 to MIC
add the Mic signal to the Tape Output. Locate J25 and J26
behind the S12 SYSTEM MONO switch on the main circuit
board.

PHONO/LINE JUMPERS

The Phono Inputs are shipped from the factory with a
Phono (RIAA equalization) preamp. Move each respective
pair of jumpers to LINE to convert each of these into line
level inputs. Phono 1 jumpers J27 and J28 are located behind
the PHONO 1 and LINE 1 jacks. Phono 2 jumpers J21 and
J22 are located behind the PHONO 2 and PHONO 3 jacks.
Phono 3 jumpers J23 and J24 are located behind the LINE 4
and LINE 5 jacks.

REMOVING THE CROSSFADER

The Crossfader may be removed from the front of the MP
24 without any disassembly of the unit itself:

1. Remove the two (2) ASSIGN knobs.

2. Remove the nuts holding the ASSIGN switches to the

cover.

3. Firmly pull the Crossfader Assembly forward, unplugging

it from the connector on the bottom board.

4. Install the replacement assembly by reversing the above

instructions.

MP 24 ASSEMBLY

In the following pages lie a rather large selection of
drawings to help with any service problems that may arise on
the MP 24. Included are full schematic diagrams, a block
diagram, component placement drawings for all of the printed
circuit boards and a diagram of the overall placement of the
PCBs and their interconnects. All of the information you will
need is found in these drawings. Begin with a thorough study
of the SCHEMATIC GUIDE found on page Schematic-5. It is
the Hitchhiker’s Guide to the MP 24!

Tracing signal through the MP 24 is easy if you refer to
the schematic and pay close attention to the connector and pin
information. The signal appears at pins on the top PCB as it
travels through the unit. You may use these as well as the pins
on the ICs to make your troubleshooting safari easier.

It may be necessary in some cases to remove the chassis to
access internal components. To accomplish this in a manner
that will make it possible to reconstruct the unit once you are
finished fixing it, please follow these simple directions:

1. Remove the three (3) philips-head screws on each side of

the front panel.

2. Remove the fourteen (14) nuts from the various ¼"

connectors on the rear panel.

3. Remove the five (5) philips-head screws holding the RCA

connector assemblies and the one securing the bracket in

the center area of the rear panel (near LIGHT OUTPUT

LEVEL).

4. Remove the three (3) knobs from the rotary controls

protruding through the rear.

5. Carefully lift off the chassis, spreading it slightly so it

clears the obstructions created by the circuit boards.

If resistance is encountered, re-check for missed screws or
sticking 3-pin connectors before you take a tire iron to it. You
(and we) will be glad you did. Having successfully removed
the chassis, the PCB assemblies will be far easier to service. If
it is required to get to some of the parts on the individual
Channel PCBs, the only way to extract these is to either
remove the top or the bottom PCBs. You must first remove
the screws adjacent to each connector or they will not budge.
Once all of the connector screws are removed from the top or
bottom PCB, you should be able to remove the board.

All integrated circuits are in sockets since active compo­nents statistically have a shorter life expectancy than their
passive cousins. Most of the ICs may be removed and
replaced without separating any of the PCBs. All it takes is a
little patience and a pair of long nose pliers with a curve at the
tip. Hang in there, you’ll get it.

If any of the sliders get noise or scratchy they can be
cleaned with CiaLube MCL

®

spray.The use of any other

cleaner may shorten the life of the sliders.

CiaLube MCL Spray is available from:

CAIG Laboratories, Inc.

16744 W. Bernardo Dr.

San Diego, CA 92127-1904 ( USA)

TEL [phone]

FAX [phone]

WEB www.caig.com

Schematics-1

Schematics-2

Schematics-3