Adjusting the pots by ear!
Adjusting your duo's pot can be a daunting task for anyone. With the high cost of replacement hardware, none of use want to permanently damage our precious Duos! Here I will try and explain in idiots terms, the adjustment of the Duo pots.
Preliminary setup:
I do my adjustments live. Meaning I have the system on and hopefully spinning / reading the disc while I do adjustments. To facilitate this, I remove the magnet from the CD lid (turn the retainer ring until it releases the magnet) And then I place a piece of tape or whatever over the lid closed switch. At this point I place an audio CD on the spindle and place the magnet on top of it to hold it in place.
Adjustment:
I use a small philips screwdriver to turn the pots. If you look closely at them, they have 4 little notches that a screwdriver fits into perfectly.
Once you have a CD in place and everything is ready to go, turn on the system. If you don't want to connect your Duo to a tv, you can use headphones instead. Press the run button on the controller. If the CD starts spinning.... Great! If not, we'll start with two of the pots:
VR102 and VR104
VR102 has a small range of adjustment in which the CD will start to spin. If you turn it and the cd starts to spin, then you know you have found one end of the adjustment. Keep turning it until the CD stops again. Once you know approximately where those two points are, you can find a sweet spot in the middle.
VR104 seems to be similar to VR102 in that there is a certain range in which the CD will spin. Again try and find the sweet spot in the middle of the two points of spin/no spin.
By this point, hopefully you have the CD spinning, and maybe even attempting to read! So lets move on to the next pot/s.....
VR101 and VR103
VR101 is kind of a by ear pot. There seems to be a small range that works for proper cd playback. Typically it seems to be in the 0 to 45 degree range with 0 degrees being horizontal. You should hear some scratchy funny noises when VR101 isn't adjusted properly. Try and find a quiet spot for it. If you go too far it will get very noisy. Hopefully you can find a spot where the CD audio will start to play.
VR103 is, from what I can tell, an error correction adjustment. Hopefully you have got a CD spinning reliably at this point. You might hear a whiney faint scratchy noise at this point.... adjust VR103 clockwise until the noise goes away. If you go too far, the noise will come back only it will be a lower tone and not sound good. Razz Try and find the sweet spot where the laser operates quietly.
VR105
Lastly, VR105.... This is an adjustment for the spindle speed correction. I'm not 100% on the best way to describe adjusting this one. Basically if the spindle speed starts to run away (go REALLY fast) then you've gone too far. Hopefully by this point, your CD will play music. Try and play later tracks on the CD and if they struggle to play, try adjusting VR105 until you can play all the tracks reliably.
