REPAIR GUIDE - TurboDuo/PC Engine Duo/R/RX: Laser Swap & Adjustment Guide

[geise]

So you're talking about the pot on the lens itself.  What about the others mentioned like VR101-105 on the board?

[thesteve]

dont adjust the pot on the new laser, as you could kill the laser.
its the ones on the system you want to adjust

[geise]

Thanks for the reply Steve.  For the high pitched weeeee sound which pots to do recommend?

[thesteve]

if i recall right it was one on the left, closest to the drive

[geise]

Did the adjustment live and did about a 1/8 turn.  Took care of the sound right away.  Everything is reading fine.  Thanks again.

[Keith Courage]

Has anyone here ever seen a duo lens vibrate and buzz? I recently had this issue on a Pcengine duo. The lens would work well for about 15-20 minutes and then just start vibrating uncontrollably right to left. Even made buzzing noises when the system was just turned on without even using the CD drive. I have fixed the problem with a new lens but man that old one freaked me out.

[thesteve]

it had a broken wire on the focus or tracking coils keith

[Keith Courage]

Thanks for the reply steve. However the same thing happened with my new lens after about 30 minutes as well so I kept at it and found the problem. It was one of the surface mount capacitors on the under side of the motherboard. Weird huh. I've never had one of those go bad on me before.

[thesteve]

that is odd keith as those rarely fail
how did you find it?

[Keith Courage]

strangely enough there was some black looking goo on the top of it so I figured I'd change it out. Also, there was a whole mess of red looking crud almost like rust underneathe it that I brushed off. Maybe that was the cuplrit and not the actual capacitor.

[thesteve]

was it a tant or ceramic?
a tant cap is my guess, as thats how they fail.
rarely does a tant or ceramic cap fail (without abuse)
ceramics tend to short suddenly
tant tend to slowly short, often recovering when power removed (causing lots of heat)

[whitecatangel]

thx very much for all info. and guide here, this thread is Gold!
cheer
darren

[whitecatangel]

thx very much for all info. and guide here, this thread is Gold!
cheer
darren

[mikebrandt]

Thanks for this guide! I'm trying a calibration but I'm a bit lost in the middle of the process... Here's the story/ My recaped duo had some difficulties reading original CDs, loading time were getting longer and longer...well my lens was dying.So i bought a new HOP-M3 and installed it crossing my fingers that it would work straight away. Well, it didn't, CD spins faster and faster then stop with the infamous "please set disc". I red the tutorial and as Cd was spinning , i by passed VR104 and VR102 adjustment. So then i aimed VR 101 with no result... all i got is this vinyl scratch alike sound or no sound at all but disc spinning faster and faster until i get the please set disc. When turning CR 101, i'm able to modulate time before the psd of death , laser seems to read with those scratchy noises but no luck...
Maybe i'm doing something wrong but i don't have a clue so here are my questions:
can we adjust the pot "live" meaning can we turn the pot(change the value)  while the disc is spinning or do we have to try a value, try to load disc, stop, change value, try to load, etc...?
Do i have to check for VR 103 now or should my CD (original audio) start to play only by adjusting VR 101?
As i got an oscilloscope at home, is there a tutorial on how adjust pots using oscilloscope?

Thanks again for this thread,

  Mike

[thesteve]

cd spinning faster means buffer empty.
start sequence is (start position)(focus hunt)(mirror detect)(focus good)(spin)(TOC read)(buffer)
your losing it at buffer or TOC
the new laser may be defective (i have seen this)
your new laser may be too bright (i have seen this too)turn pot on lens CCW 1/8 to 1/4 turn and try again
yes adjust live.
I havent seen a tutorial using a scope, but i should do one based on pioneer instructions, as i have them handy.