VR102 soap opera

[Slypty]

Just got a new laser in, and found that my old Duo laser was really weak.  Not much good news after that, basically I'm finding that after adjusting my POTs, I can confirm good positions on VR105, 103, and 101.
 
  It's VR102 that is a big distress..  Seems if I manage to boot a game, when the laser goes to the outer edge, the disc stops for a second and decides to spin backwards.  Usually the laser gives up at that point.  Yesterday I could get it to move at the correct Duo speed and read a game, so I tried a back up CDr.. and it read some of it but would lag for a long time between scenes.  So I continued to tweak, and now I'm F'd.  Can't get that place again with the VR102.

  I noticed you can turn the POT many times around, is this a bad idea?  Also, even after marking points on the POT to return them to after adjusting, when I return them the laser behaves differently.  It's super frustrating getting so close but not close enough. 

  Any tips at this point?

[Keith Courage]

I've actually come across some systems where the potentiometer itself had gone bad. so it could need replacement.

however, before considering that, has your system had the capacitors replaced yet? Old capacitors are a big reason for the CD drive not working correctly.

[Slypty]

Yup, caps are complete.

 So just to get this straight, if a POT is bad it will still make a difference, but just isn't fulfilling its' needed spec requirements?

[blueraven]

Just got a new laser in, and found that my old Duo laser was really weak.  Not much good news after that, basically I'm finding that after adjusting my POTs, I can confirm good positions on VR105, 103, and 101.
 
  It's VR102 that is a big distress..  Seems if I manage to boot a game, when the laser goes to the outer edge, the disc stops for a second and decides to spin backwards.  Usually the laser gives up at that point.  Yesterday I could get it to move at the correct Duo speed and read a game, so I tried a back up CDr.. and it read some of it but would lag for a long time between scenes.  So I continued to tweak, and now I'm F'd.  Can't get that place again with the VR102.

  I noticed you can turn the POT many times around, is this a bad idea?  Also, even after marking points on the POT to return them to after adjusting, when I return them the laser behaves differently.  It's super frustrating getting so close but not close enough. 

  Any tips at this point?

Try This:

https://www.pcengine-fx.com/forums/index.php?topic=8926.msg152736#msg152736

This was the trim pot guide we put up 8ya

Hope it helps

[Keith Courage]

Yup, caps are complete.

 So just to get this straight, if a POT is bad it will still make a difference, but just isn't fulfilling its' needed spec requirements? 

Pretty much.

Also, have you messed with V101 at all? This can have a huge effect on things.

One last thing to check is that it's not uncommon for the red wire for the lens wires that hooks up to the lens itself to get a short in it or fall out completely. Double check that red wire is getting a good connection on both ends using a multi meter. Symptom of a bad connection here is the lens moving and return really fast over and over again when trying to read a disc.

[Slypty]

Try This:

https://www.pcengine-fx.com/forums/index.php?topic=8926.msg152736#msg152736

This was the trim pot guide we put up 8ya

Hope it helps[/quote]
Thanks I did try that at first, I might give it a go again from head to toe.

[Slypty]

Pretty much.

Also, have you messed with V101 at all? This can have a huge effect on things.

One last thing to check is that it's not uncommon for the red wire for the lens wires that hooks up to the lens itself to get a short in it or fall out completely. Double check that red wire is getting a good connection on both ends using a multi meter. Symptom of a bad connection here is the lens moving and return really fast over and over again when trying to read a disc.[/quote]
  I'll take a look at the red wire, it would be weird if both lenses had the same issue since I've been through one with similar load problems already. 

 As per VR101, I did mess with it but find that it's in a good spot, I don't want to go a full rotation since I may risk ruining the POT, unless you think it's safe to turn a pot more than 360?

[Keith Courage]

I'm just saying that if V101 is off then you won't be able to get anything to work. If you definitely have it in the spot where things were working before then I'd leave it alone.

[Keith Courage]

hey, I just read your first post again. So the lens will move, get stuck, and then the disc spins backwards? When this starts to happen again try and move the lens motor manually near where it usually stops to see if it will progress further. When the lens motors go bad they get stuck here and there which usually causes the disc the then spin up all funny like. Sometimes a fast spin up but usually a slower spin instead.

Kind of hard to diagnose this without seeing exactly what happens in person.

[Slypty]

hey, I just read your first post again. So the lens will move, get stuck, and then the disc spins backwards? When this starts to happen again try and move the lens motor manually near where it usually stops to see if it will progress further. When the lens motors go bad they get stuck here and there which usually causes the disc the then spin up all funny like. Sometimes a fast spin up but usually a slower spin instead.

Kind of hard to diagnose this without seeing exactly what happens in person.

I do move the V101 a bit to see if it helps, I might have put it in a spot the other pots don't like as much.  Have to get tinkering again this morning, will post results.  Thanks for the help, I'll see what happens.   Just to elaborate on the backward spins, it only occurs when the laser goes to the outer edge.  When I adjust V102, sometimes I can get it to spin forward from that point.  It will go to the edge, then in a little bit and continue to read.  There was one time I had it reading near the far edge at the speed Duo games should be read at, which is really pretty slow.  I haven't been able to repeat.

  So, ya if I screw with the V102 a little I can occasionally get it to move forward, but it's really hard to find that point, and when I do back up games don't necessarily read well either.  I tried small adjustments when I got to the sweet spot, and lost it because I wanted to play a few back ups. 

 On a sidenote, does CDR media quality make a big difference?  I'm using cheapo Ridata I think.

[Slypty]

After more adjustments, unfortunately little progress. I was able to see that the V101, when adjusted controls where the laser moves to some extent.  For instance by turning it 1/3rd, the result is that the laser won't travel to the outer edge to read the game, but the game also doesn't proceed unless the laser goes to the edge..

 What I find unusual is that I can boot up a CDR game, and play some of it.  Once it goes to the edge, the same problem occurs as with an official game, something's wrong with the travel point of the outer edge, and the disc wanting to turn backwards.  I actually had the backup CDR moving really fast backwards for a while, it was just after the lens went to the edge and about 10 minutes in to the game. 

  I guess changing the pots might do it, I'll double check my laser caps again to make sure I haven't reversed or created a bad connection.

  Also should note that at one time, I had it running so that the laser would go to the edge, and return about an inch and continue to read games.  I haven't been able to get it there again.  I wonder if I've burned the laser out with so many adjustments. 

 Finally the C102 Cap, which is supposed to be 3.3uf 50V, is 3.3uF 35V.  I've read that this Cap needs to be 50V, but I'm not sure how important that is.

[Keith Courage]

some Duos will have issues reading CDrs if they are larger games. can also depend on what kind of media you are using. Some drives like certain brands over others. try testing a game that's 500 megabytes or smaller. anything over that can have issues where the lens can get stuck near the end of the track regardless of what adjustments are made.

[Slypty]

some Duos will have issues reading CDrs if they are larger games. can also depend on what kind of media you are using. Some drives like certain brands over others. try testing a game that's 500 megabytes or smaller. anything over that can have issues where the lens can get stuck near the end of the track regardless of what adjustments are made.

Thanks, but this problem seems to happen with original games as well.  I've ordered some new pots, hopeful I get this working in a few weeks.