I was having a hard time finding the problem with this Mackie 1604 unit. I didn't have a schematic. Went looking on the web and found your site and the price was more then reasonable. Ordered it and within the hour had the manual and within 15 minutes had the unit fixed. Best $4.99 I ever spent. Thank you.
Text excerpt from page 4 (click to view)
SECTION 1 SERVICING NOTE
HOW TO OPEN THE DISC TRAY WHEN POWER SWITCH TURNS OFF
1 Remove the Case.
3 Pull-out the disc tray.
2 Turn the cam to the direction of arrow.
Note for Installation (ROTARY ENCODER)
Note:When attaching the Base unit, Insert the section A into the groove of BU cam.
Section A Groove
Note:When attaching the BU cam, engage the Rotary encoder switch as shown in the figure.