Definitive pc cd /tg cd pot adjustment guide?

[pas7680]

I was wondering guys is there was a definitive guide on adjusting the pots on the pce cd? i read threads where people mention using frequency probes and oscilloscopes but can't find no actual guide on doing this.

I was fortunate enough to pick up a box full of ifu systems on a recent trip to Japan and are in the process of refurbing them and it would be nice to have a guide to the cd drives.

i don't currently own a oscilloscope or anything like that but would purchase one if that's the best way to calibrate the drives.

[schweaty]

Dude,  there is sticky on this page that does exactly that.  Laser swap and adjustment guide?

[pas7680]

i think you must be looking at the Turbo Duo sticky.....

Neither the tg cd laser swap guide nor the capacitor replacement and adjustment sticky have the info in them

[780racer]

Addendum:  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.   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.





Copied from Somewhere else...

Is this not what you need? I think we are not understanding what you need. Hope the above helps.

[pas7680]

no that's not what I'm after, those instructions are basically random testing.

There is supposedly exact measurements you can get using frequency readers and oscilloscopes.

Also the above guide is copied from the DUO guide, i'm taking about tg16 cd / pce cd - are the pots the same?

[ConHuevos]

1)  Pull the RF signal from pin 2 on the P5 connector, and ground it on pin 1 of P5.
2)  Set your scope to 2.00V/Div and 1.000us/Div.  Get your readings while your CD system is trying to load the disc.
3)  While the CD attempts to load, use a plastic or other non-metal small Phillips-head screwdriver to turn VR102.  You're trying to get the greatest amplitude (biggest wave) you can.  Once you've found the spot that makes the wave as large as it can be, move on to VR101 and do the exact same thing.
4)  After you've made the biggest wave you can, set your scope trigger to be at the far left of your screen, and about 3/4 of the way up the waveform you're pulling.  Turn VR104 clockwise until the disc stops spinning.  Once this happens, make the smallest turns you can COUNTER-clockwise and wait a few seconds between each turn to see if the disc starts spinning.  Once it does, move on to VR103.
5)  VR103 is kind of the odd pot out - it's incredibly touchy, and it seems to vary on a per-Duo basis how to set it.  Ideally, you want to turn it until your drive is making no real noise - no squeaks, no whines, no chugs or repetitive clicking noises.  It should run almost silently.  You can find your starting point by turning it counter-clockwise until it starts making a faint whine-like noise.  When this happens, turn it CLOCKWISE by a hair, and I do mean 'just a hair'.  I'm not exaggerating when I say that the VR103 pot has a very small window of operation.  Use a game with a soundtest available right off the bat, like Rondo of Blood.  Playtest the first and last tracks while making minute adjustments.  There should be no crackling or audio dropouts at all.  This can take some time, so be patient, and you'll pull through.