Mellotron M400 Preamp and Line Amp

[CJ]

both boards located in the control module with slide in slots

thing started working after de-oxit, equipment coming out of hibernation after two years can be crusty.

 

[CJ]

front

 

[CJ]

back side of boards, locator slots are in different spots so you get the boards plugged in right.

 

[CJ]

better focus after removing fingerprint from lens, preamp on lefter, line amp right,
BC239C and ME 0402 in preamp, BC267 and ME 0402 in lne amp,

 

[CJ]

input level has to be low or you get sq wave out the back, 10 mv P-P max, tape heads must put out low V.

gain of preamp goes up from 60 to 800 when unloaded by tone/vol circuit.

no schematics online, evilbay has a pay for manual, so we traced it out old school, so there you go.

 

[Blue Jinn]

Thanks for this! You wouldn't happen to have a PSU schematic or a CMC-10 schematic? (Does your 'tron have the CMC-10 or a newer motor control board?) There's a hack on gearspace that supposedly makes the CMC-10 more stable. I have several bad ones that I'd like to try and fix and then try out that hack.