QA-101 v3.2 Modification Instructions

The modifications required are:

1.      Change the µC clock crystal.

2.      Insert 100µH choke in series with µC power supply.

3.      Change the firmware EPROM.

Remove Main Circuit Board:

First you need to remove the main circuit board from the QA-101.  Unplug the AC power cord from the player.  Remove the four screws on the bottom of the chassis, which secure the top cover.  Remove the top cover by sliding it toward the rear of the QA-101. 

Disconnect all connectors on the main PCB (16-009).  The white 6-pin plugs should be removed by pushing them out of the sockets with a small flat-blade screwdriver or other pointed object.  There are small slots on each side of the socket for this purpose.  Do not pull on the wires.  Remove the ribbon cables by moving the locking arms outward.  You can now remove the five screws holding the PCB.

Change the Crystal:

To change the crystal, simply unsolder the existing crystal X1, and install the new 24 MHz crystal.  The orientation of the crystal doesn't matter.

Install the Inductor:

To install the 100 µH inductor (which looks like a resistor), you must first cut the trace on the printed circuit board which supplies +5v to pin 40 of the microprocessor U5.  The enclosed photocopy shows where to make the cut.  You just want to separate pin 40 from the power trace running along the top of the chip.  Use a small flat-blade screwdriver or other pointed object to make the cut.  You can see if the trace is cut though, by holding the board up to the light.  You should also check to see that there is no longer continuity between U3 pin 14 and U5 pin 40.  Now solder the choke between U5 pin 40, and the +5v supply as shown on the photocopy.  The orientation of the inductor doesn't matter.

Mount the board in the chassis, and connect the connectors.  You may need to use a tool to get some of the connectors into their sockets, as there is not much room for your fingers next to the CD mechanism.  Try not to pull on the plug that goes to J4, as the other end is connected to the circuit board under the CD tray.  You should look under the CD mechanism to make sure that the other end of J4 has not pulled loose.  You can push on the other end with a screwdriver to make sure it is still in the socket.  If the QA-101 won't play after you put it together, this is the most likely reason.

Install the new EPROM:

The firmware EPROM is an integrated circuit located on the main circuit board labeled 16-009.  This IC is in a socket labeled U4.  It should have a label on it with the Clover Systems logo.  Remove the chip from the socket using an IC removal tool or small screwdriver.  Gently pry the chip from the socket, being sure that you are prying up the chip only, and not the socket.

Installation is simply a matter of pressing the new IC into the socket.  One end of the EPROM IC has a notch in it.  Align the chip so that the end with the notch is facing the rear of the QA-101.  Make sure all pins go into the holes in the socket, and press the IC into the socket.

Slide the top cover on from the rear of the chassis.  Notice that the top cover has a lip on one side that engages the front panel.  If you have trouble getting the top cover to align with the top flange on the front panel, use an ice cream stick (or something that will not scratch the paint) to gently pry it into alignment.  Be sure that the display cable does not get pinched in this lip when you engage the front panel.  Use  the ice cream stick to push the cable out of the way if necessary.