TG CD dock Distortion.

[Desh]

I have a bit of a strange problem I have found no info on and wondered if anyone else has had a similar problem.  About 1 year ago I scored a dock base with the original power supply.  A few months later I sourced a CDrom2 to add to it.  There was always some light video distortion and a lot of sound distortion when the lens was moving to read the disk.  Once loaded everything is perfect. 

My CDrom2 was cheap and noisy so I always figured it had issues.  Recently, I decided to fix up that CD ROM and my dock.  I did a full recap on the dock and CD ROM, shortly after the laser went out on my CDrom2 so I replaced with a good "low mileage" laser and adjusted the pots.  Everything was working fine but I still had the same distortion.

The CDrom2 had been converted to a 2 gear drive setup and I figured that caused the drive motor to work s bit harder.  I even suspected the drive motor was on it's way out so I replaced it with one I knew was quiet.  Still no change.

I decided to just live with it but suspected the 2 gear drive setup may be causing a bit more amp draw on the drive motor, thus causing the distortion.  Just today I received a good working TG CD ROM from Jelloslug.  The CD unit itself is more quiet but I still have the video and sound distortion.  This means my problem must be in the dock itself.

I was thinking about adding caps to the direct lines going into the a/v jacks but I figured I'd check with the gurus here and see if they've dealt with something like this before.

[Keith Courage]

2 gear setup does not effect the audio whatsoever. I have installed many 2 gear setups with no distorted audio as a side effect.

I encountered this problem with a pc engine briefcase setup before and it turned out something was wrong with the ground. I tapped ground from somewhere else on the board and ran it to the grounds for the RCA jacks and it fixed the problem.

This might resolve your issue as well. 

[Desh]

2 gear setup does not effect the audio whatsoever. I have installed many 2 gear setups with no distorted audio as a side effect.

I encountered this problem with a pc engine briefcase setup before and it turned out something was wrong with the ground. I tapped ground from somewhere else on the board and ran it to the grounds for the RCA jacks and it fixed the problem.

This might resolve your issue as well.

Yeah... my first thought was that the 2 gear may have been contributing but once I put a stock drive on and it did the same thing, I knew it wasn't the issue.  I actually would prefer to use my assembly with the 2 gear setup.

Thanks for the info.  I honestly haven't opened it back up yet (I will tonight) and I will double check the ground to the RCA jacks.  Also, when you tester the briefcase setup was there zero continuity to the original ground or just high resistance?

[Keith Courage]

I didn't actually check the connection. to me the wonkey audio and video I was getting seemed similar to when an rca cable shorts out so I just tried adding another ground which worked.

another possibility is that some of the capacitors in the docking station have gone bad but I've never come across that. maybe someone else here can chime in and say if they have had this problem before and if it was cap related or not

[thesteve]

only TG16 dock failure ive seen was bad RAM
causing graphic glitches and crashes

[BlueBMW]

Dumb question.. have you tried cleaning the contacts where the cd drive connects to the dock?  I've had dirty contacts there cause a myriad of issues.

[Desh]

I didn't actually check the connection. to me the wonkey audio and video I was getting seemed similar to when an rca cable shorts out so I just tried adding another ground which worked.

another possibility is that some of the capacitors in the docking station have gone bad but I've never come across that. maybe someone else here can chime in and say if they have had this problem before and if it was cap related or not

Caps should be good, they are all new.

I did have a chance to open it up last night and poke around on a few things. 

Problem 1: when I opened this thing (it is the second time I've opened it because I recapped it before) a small phillips screw fell out of somewhere.  I can't find where the damn thing would have even gone.  There's a possibility this thing was sitting on the board somewhere and bridging a connection/ connections

Problem 2: The small board that holds the RCA jacks and power jack has 3 ground sources going to it.  One comes off the board and through a disc style capacitor and attaches directily to one of the mounting screws for the main board and on to a copper ground pad.  This connection seemed a bit loose (that would have been my fault).  The copper looked fine but I cleaned it anyways and tightened the connection.  The other two sources go to two separate plugs on the main board.  I checked all of these connections and checked resistance through the wires themselves.  Everything here seemed OK.

For shits, I put the thing back together to see if there was a change.  To my surprise there was!  I no longer have any sort of video distortion when loaded and although I still have some light sound feedback it is nowhere near what it was before. 

Dumb question.. have you tried cleaning the contacts where the cd drive connects to the dock?  I've had dirty contacts there cause a myriad of issues.

     

I didn't even think to do this but I will.  I may also add additional grounds directly to the RCA jacks and see if it cleans up any of the remaining light distortion. 

As always, thank you guys for all the help and input.