Gearporn: Korg Monologue teardown


#1

Someone (panelist) on the Elektronauts forum discovered points on the Korg Monologue PCB labeled ‚high boost‘ and ‚low boost‘. They seem to alter the EQ or overdrive.
Since I couldn‘t find any pictures of the inside of the Korg Monologue, I opend my unit up and took some photos.

Here is a link to my Flickr album: https://flic.kr/s/aHsku9z8Qd

Here are some additional informations:

All potentiometers are mounted with nuts to a plastic chassis which holds the interface PCB. The pots have a really nice quality (metal shafts/no wobble) and feel more sturdy than the pots on my Moog Sub37!

There are three microcontrollers inside: two on the main-pcb and one on the interface-pcb.

Additionally to the low- and high-boost points there are lots of other test points on the main-pcb. They are labeled: D, W, M, S1, A2, S2, P2, F, P1, A1, N, A, R.

All ICs and electrolytic capacitors are marked with a black line (was hard to read the labels of the ICs).
Also the nuts from the pots are marked with black lines.

Here is a list of almost all ICs:

IC2 SPANSION (now Cypress) FM3 MB9BF324M (32-bit ARM cortex M3)
IC6 ST TL084 (general purpose JFET quad operational amplifier)
IC7 TI CD74HC4053 (triple 2-channel analog multiplexer/demultiplexer)
IC8 ST TL084 (JFET quad operational amplifier)
IC9 TI SN74LV04A (hex inverter)
IC10 JRC NJM4580 (dual operational amplifier)
IC11 TI TL064 (low power JFET quad operational amplifier)
IC12 TI TL064 (low power JFET quad operational amplifier)
IC14 SPANSION (now Cypress) FM3 MB9BF121M (32-bit ARM cortex M3)
IC15 TI TL064 (low power JFET quad operational amplifier)
IC16 TI CD74HC4053 (triple 2-channel analog multiplexer/demultiplexer)
IC17 ST TL084 (JFET quad operational amplifier)
IC18 JRC NJM4556A (dual high current operational amplifier)
IC19 TI TL064 (low power JFET quad operational amplifier)
IC20 TI TL064 (low power JFET quad operational amplifier)
IC21 ST TL084 (JFET quad operational amplifier)
IC22 JRC NJM13700 (dual operational transconductance amplifier)
IC23 TI TL064 (low power JFET quad operational amplifier)
IC24 ST TL084 (JFET quad operational amplifier)
IC25 TI CD74HC4053 (triple 2-channel analog multiplexer/demultiplexer)
IC26 TI CD74HC4053 (triple 2-channel analog multiplexer/demultiplexer)
IC27 TI TL064 (low power JFET quad operational amplifier)

PC1 Toshiba TLP2368 (high speed optocoupler)

X1 ROSON 4.000F20EJK (4MHz crystal resonator)
X2 ROSON 4.000F20EJK (4MHz crystal resonator)


#2

My KORG Monologue inside:

DRIVE value from KORG Monologue: https://www.youtube.com/watch?v=qynZkqb2LlA

The filter is very nice, but output have little noise (VCO level down).

Greetings from germany. Rolf