REPAIR GUIDE - Super CDROM2: Total capacitor replacement chart

[bust3dstr8]

What's the size of of the Torx on these units.....my unit just shit the bed.

[mrchuck999]

bust3dstr8, You need a Torx-10 security bit to open your super cd-console and duo-r/rx.

[mrchuck999]

Hi Guys,
Has anyone identified the audio section in the Super CD ROM2 Add-on unit?
I would really like to just start with the caps that are in the audio-section as seen with the duo.

[BlueBMW]

I've got three units im working on right now.  Ill see if I can isolate it.  I think its mostly in the area of that removable sub board though.  That's where I see some op amps

[mrchuck999]

farankoshan,

Since you have replaced many caps in the super-cd unit, with no sound-fix.
Could you please share which caps were replaced?  I could then slowly replace the ones you did not on mine and we may be able to locate the audio section of the board more quickly.
If all else fails, I will be working my way through every section bit by bit until I locate the audio section.

Thanks to everyone here. This forum is great resource for NEC owners.

[mrchuck999]

BlueBMW,
Thanks! I was guessing that section would be it. (we'll see).
 It sure looks promising. It also contain a lot of caps which I think I'll have to use the little SMD's.

[farankoshan]

Just wanted to update on my "crackly sound" that didn't go away after the full cap replacement (see page 1):
Once I replaced the lens on my unit, the sound problem disappeared completely. Now, whether it was the new lens that fixed it, or the extra cleaning of the board after the new lens was installed, the sound comes out clear.

So to whoever may be struggling to fix a sound problem, keep the above info in mind.

[thesteve]

cd read errors sound crackly too

[farankoshan]

farankoshan,

Since you have replaced many caps in the super-cd unit, with no sound-fix.
Could you please share which caps were replaced?  I could then slowly replace the ones you did not on mine and we may be able to locate the audio section of the board more quickly.
If all else fails, I will be working my way through every section bit by bit until I locate the audio section.

Thanks to everyone here. This forum is great resource for NEC owners.

Well, as I mentioned on this thread, the sound problem didn't go away with the COMPLETE cap swap, or even with new caps on the areas isolated by many of the earlier posters. However, it must be said that it was only after the lens was swapped with a new one that the audio problems disappeared completely. So in my case, I can't really say which caps helped most with audio, but just change them all, since caps all fail with excessive use eventually, and the whole board is connected, so leaks & failures are bound to affect another component. And caps are cheap anyway. If the problem persists, then opt for a laser change, because as with my unit, that fixed everything right away.

Hope this helps.

[Keith Courage]

Okay everyone, I have found a solution for the distorted audio people have been experiencing on these CD drives. Hopefully this doesn't pertain to just this drive I fixed and will work for many others of you out there plagued with having distorted audio within the first 5-10 minutes of usage even after an entire electrolyte capacitor change.

This issue was driving me crazy recently since I changed out all my caps and still had the same issue. Whether it was with Hu card sound or CD rom sound I had distorted audio for the first 5-10 minutes and then it got better.

I found two small surface mount resistors that had gone bad on the audio circuit. One for the right channel and one for the left channel. You can change these if you want or just bypass them with a wire. In my pic I had actually removed the bad ones(this was to make my testing easier)but you really don't have to. You can check to see if it fixes your problem by just touching a wire from one side to the other before doing any soldering or making changes of any kind. Try it and see if your audio goes from distorted junk to crystal clear audio. I have circled the two bad resistors in the zoomed in pic below.
I have also included a larger pic so you can see what section of the board they are on.

[thesteve]

those look like 1k resistors to me.
if jumpering them improved it, it means you have a bias current issue on the transistors.
look for  voltage issue around them.

[Keith Courage]

ah my mistake. I was trying to look up the part online and all I could find said they were capacitors.

[thesteve]

more to the point, your solution addresses the symptom, not the cause and could burn the transistors.
it does indicate that your very close to the cause.
if you trace out the circuit, and follow the current you will find the cause.
i suspect a damaged trace or via, causing reduced current to the transistors.

[mrchuck999]

Hi Guys, This might not be the proper place for this question, but its surely the most knowledgeable group for the SUPER-CD-ROM2 Unit.  Q:  What is the expansion port (I/O port) under the console for? Did NEC ever make an add-on to fit into this I/O port? What would it be used for ?  I am guess a game-save-memory expansion, but that's a total guess. Does anyone have a pin out to see what this thing is capable of?
Thanks.

[choijimmy]

Keith's solution works fine for me. My sympton is got low volume/ static sound from the Super CDROM AV port int he first few mintues. After warming up, the sounds back to normal level and no more static.  If I plug the AV cable from the coregrafx AV port, No warmup at all.

I replaced all capacitors on the boards but still No luck. Keith suggested to jump the wire for the resistors on the sub-board in red circled ( attached ). Then it works perfect! No more warmup even I plug the cable into Super CDROM AV port!

Thanks Keith!
Jimmy