PC Engine Duo RX Pot Knob Caibration HELP!!!

[terrybogard]

I tried changing the pot knob locations but still wont work. I tried 2 lasers which I know work since i tested them in my Duo R. The knobs on the duo RX are big and white with numbers on them, alot different than the duo's. Can someone help me calibrate them to the correct locations? Please help maybe get me a pic or something.... Thanks in advance

[NecroPhile]

Unfortunately, you're stuck with trial and error to get it adjusted properly.  I don't think there's a universally correct setting; if there was, there'd be no reason for them to be adjustable in the first place, so good luck with the fiddling. 

P.S. - Make certain that the cd assembly is properly reinstalled.  A few peeps on here have had problems with the shroud around the laser being ever-so-slightly too high, making the laser too far away from the disc to focus.

[terrybogard]

the problem is there are 4 knobs with endless possibilities when trying to find the right combination.... Its literally impossible to figure it out.... I need help or guidance....

[terrybogard]

Ok i found this information on the forums:

  A
   |
 -----
| VR |
 -----
 |    |
 B  C


vr101:AB=12.33 AC=10.65 BC=19.55
vr102:AB=7.89 AC=8.11 BC=11.28
vr103:AB=7.25 AC=7.14 BC=18.46
vr105:AB=0.38 AC=0.00 BC=0.38

Now can anyone tell me what the hell this means? I understand the diagram with the VR symbolizes the knob and the optional locations you can put it in but what the hell does the rest mean and how do i use this to help my situation lol. Thanks in advance to anyone who replies

[blueraven]

@terrybogard,

Please reference this thread, If your question hasn't been answered by Monday I'll do my best to help. VR102 is the laser focus pot, iirc.

Unless you have a Duo RX (not sure about the R) There are actually 5 knobs, you missed vr104.

https://www.pcengine-fx.com/forums/index.php?topic=3586.0

blueraven

[BlueBMW]

When I was fixing the two broken duos I had, I ran the unit with the cover off, tape over the door close switch and the magnet holding the disc on.  I'd run the system and carefully adjust each pot with the system running. 

VR101 seemed to affect the noise coming from the laser, when it was too far off the sound would garble.  I adjusted this later once I got the unit to spin up a cd properly.
 
VR102 had a very narrow range in which the laser would pick up the CD and request it to spin.  Any other spot and the unit would do nothing.  This was the first POT I adjusted.

VR103 also seemed to affect noise level of the laser.  Eventually you'll find a sweet spot with this pot and VR101 in which your laser is quiet.

VR104 seemed to affect things similar to VR102.  IF it was too far off, the cd would stop spinning.  Typically I tweaked with VR102 and VR104 first.

VR105 seemed like a final fine tune POT.  If its off, things wont work right, but you can get things mostly functioning before you adjust it.  It also seemed to affect noise level a bit.

Finally, I used an audio cd to do the adjustments, mostly because it was constant CD access across the whole disc and you had audible feedback throughout.  Sometimes I could get a CD to play up to a certain track and then it would start to struggle after that. 

Of course, all of this is on a US Duo, not an RX.  Though the effects of the pots might be the same.  If this helps, great, if not, sorry to waste your time 

Also note, I did NOT adjust the plastic adjuster on the laser unit itself.  I tried, but in the end it seemed like the factory position was the best location for that unit.  It must be a factory calibration setting.

Here's a picture of the pots on one of my DUOs where it ended up fully functional.  Now my second duo was a bit different than this one which tells me each system is different.

/tduopots.jpg