REPAIR GUIDE - Super CD-ROM²: Total Capacitor Replacement Chart

[BlueBMW]

Did you replace all the capacitors or just some of them?

[pnauts]

for the moment I replaced 2 leaded capacitors, I didn't change SMD.

[BlueBMW]

Ahh....  I would highly recommend you just go ahead and replace all the capacitors.  Its a pain but will save you headache in the future.

[pnauts]

well, I'll perhaps change leaded and the ones which are under the top RF shield.
Others are accessible later just by removing the laser unit.

[pnauts]

Hi, after cleaning under the 1000µF and had the capacitor changed, sound is better but I'm not sure with the results.
Volume from SCDR² AV connector is lower than Console AV connector, is it normal ?
The voltage on pin is around 0.6V, I don't see any residues on the coper wires and vias between the components mentioned in my post above. The diodes measured on Q308 and Q309 (PNP) are ok.

edit: to be more accurate, the voltage is around 0V but after something like 10 minutes of run, with an initial voltage of around 1V with cold start, so there is a drift but for the moment I didn't succeed to find out. The volume on SCD² seems lower than direct to console anyway.
I'll reflow welding around this components tomorrow.

[BlueBMW]

I've typically noticed it to be a little quieter from the SCDROM2 versus the core system.

[thesteve]

that voltage should start higher then bleed off (sounds like its doing that now)

[pnauts]

then the sound beginning a few lower and a little crackly is normal ??
I measured a low resistance at ZD303 (around 90 ohms between A-K), I don't find where it come from.

[pnauts]

Up, please.

[pnauts]

I think it's fine, I changed some others leaded capacitors + test with RF shield, the voltage is around 0.5V at start up then decrease, a SCDR² is reborn, great ! and thanks for help I appreciated it.

[Raulie]

Does anyone know what happens when the RF shields aren't installed?

[schweaty]

i could be wrong about this and someone please correct me if i am, but i believe the bottom shield is part of the grounding for the system.

[Ergot_Cholera]

I have the same issue of low, scratchy audio for the first few minutes of operation and then it gradually improves. I have replaced all the capacitors.
 I haven't tried any repairs yet but I would like to know what the resistor size and value are on the 14T board that need to be replaced (shown circled in red on image), I don't just want to jumper them as I'm sure this could lead to problems (they're there for a reason right?).
I already cleaned the board with alcohol when I repaced the caps, but I will try again and maybe see if that antithump thing is running at the correct voltage.

[choijimmy]

I have tried to using both 1. jumping wiring  2. Cleaning the pcb.

I use ultrasound cleaner to clean the PCB ( I don't have disk washer ), however, my ultrasound cleaner is Not big enough to put the whole PCB into in. I am only able to clean the part which around the 1000µF cap area. The result is pretty surprised,  I am able to get 70% of sound volume in first 5 mins compare to jumping wire method. After five minutes warming up, the PCB cleaned machine has same sound volume compare to jumping wiring one.

I believe if my ultrasound cleaner is big enough to clean the whole PCB, it will  solve the problem completely.

I don't see the point by replacing the resistors since the root cause is not those resistors. You should clean the PCB thoroughly( just clean the PCB by using alcohol  with cotton swab won't help because leaked cap fluid is all over the via holes ). If you are not comfortable by cleaning the PCB in disk washer, ultrasound cleaner, Jumping wire is you last resort. I have a mahine which jumping the wire for around 1 year and use pretty often, so far no issue yet.

[Ergot_Cholera]

I misunderstood the resisitors information as I just scanned over it.
Unfortunately I don't have access to a dishwasher or an ultrasonic cleaner, so I suppose I might have to reluctantly try the bridging method.
I suppose I could just use the AV socket of my Core Grafx instead of the Super CD-ROM². I only just learned that this could be done, which basically means that there is no need for an AV out on the Super CD-ROM² (unless you are using an original PCE maybe?).
I tested the voltage on the centre pin of the sound board (antithump?) and got 1.13v, so I know that this is probably the issue. So thoroughly cleaning around the 1000uf cap will help? The original cap did have some leakage when I removed it but I cleaned the whole are around the heatsinks with alcohol, but I guess this wasn't enough.

[Vimtoman]

I've had the same problem and cleaned and reworked with solder the power input circuit and this solved the problem.

But I do have a problem with the drive not reading cdr's where it was ok before.

There are two jumpers on the Super cd-rom2 called J1 and J2.
One is for the shielding problem and joins two sections of the Gnd.
The other is for the 5V that's may be missing from your Video out Din connector.

[pnauts]

Did someone have the schematic on the power supply from jack socket to 7805 input, from what I remind there is a power diode, then a PNP mosfet and NPN mosfet with some zener diodes.

[thesteve]

the shield is for noise supression only, will run fine with them removed

[Vimtoman]

Just done a total recap and now my drive is clicking and searching but not loading cd's.
I've checked all caps and they are the correct value.
Is there any caps that need to be a particular spec?

[thesteve]

the ground on the plate over the mech is required

[Vimtoman]

All shielding in,
It look like it was the missing cap mentioned at the beginning of the thread next to the Sony IC.
I had not put it in.
Popped a 100µF 16v in and it's reading disks now.
Still clicking more than normal though.

Any idea what the cap is connected to?

[PCEngineHell]

All shielding in,
It look like it was the missing cap mentioned at the beginning of the thread next to the Sony IC.
I had not put it in.
Popped a 100µF 16v in and it's reading disks now.
Still clicking more than normal though.

Any idea what the cap is connected to?

If the laser eye is making clicking sounds as it seeks/reads, it may need to be calibrated, because it is not staying focused.

[Vimtoman]

What needs tweaking?

[thesteve]

i was thinking the CDR2 not the SCDR2, so on that the shields are less critical
the needed adjustment would be a guess at best without the unit handy, but focus level would be likely if the laser was replaced

[Vimtoman]

I've managed to adjust it so it's not clicking that often.
reads all disks now.
Not sure if I'm being over critical.

[pnauts]

Hi guys,

I try to help someone who did recap a SCDR² and it doesn't work in RGB now.
the cable works fine with the core.
I asked him to try simple link from expansion port (with its Sodipeng cable)
there is just CVBS for sync, 0V and 5V for fast blanking in Scart 16, then 2 colors through the Sodipeng.
here are the results the colors are added and saturated there is no additive colors.




the CVBS works fine when pin 16 is removed, all in grey with 3 colors when plugged.
Any idea ?

[thesteve]

that tv  (FS120?) doesnt do RGB

[pnauts]

nope, it was a problem with the sodipeng amp not wired, so is problem fixed for RGB, but still a little sync problem, when CVBS is connected directly from expansion port to SCART 20 it works (original wire from DIN cable is removed), when cable is normally use and a wire cabled between expansion port and pin 3on the Din there is some deformation/waves on a side of the TV

edit: fixed.

Another one.
Lens go up and down, beam is visible then "set disc" message ?
The SCD² was recap by a non professional of the job.

[SegaSonic91]

I just bought a SG+SCD2.  I was wondering if the SCD2 is as bad as the DUO and MCD cap wise?  DUOs ALWAYS need re-capping, did the SCD2 use the same shitty SMD caps as the DUO or is it a bit better in the cap department?  I will re-cap it anyway, I just want to know if I will face something as bad as the DUO I bought a while back.  Several caps had corroded the board so badly, they had fallen off.  I have to use the vias for those because the pad has been eaten away.  If the SCD2 is in the same boat as the DUO/MCD/Game Gear, I will make sure I have the caps ready, on hand once the system is on its way to me.

[BlueBMW]

In my experience the SCDROM2 is just as bad as the Duos etc but we havent seen it as much since its a little bit newer of a unit and less common.

[MNKyDeth]

I bought a SG+SCD2 about a month or two ago. It needed the caps replaced. The caps did not damage anything yet but they were leaking.

I recap all NEC consoles I come in contact with now. Even if they work and/or technically don't need it. Imo it is just a smart move. I even recapped the SuperGrafx Even though it worked just fine.

[thesteve]

these have sound issues from the residue due to trace proximity, so be sure you get it washed good

[SegaSonic91]

Thanks for the info, guys.  About the area of the board with low clearance, what is the best way to replace those caps without using wires?  Is it OK to use ceramic SMD caps there?  Is there something different you would all recommend?

[MNKyDeth]

Here are some pics of the area on my Super CD-Rom 2 unit.




The way the expansion board is laid out the caps are just behind the other ones on the main PCB. There is one cap in that area on the bottom at C63? but I used a ceramic cap in that spot so clearance was not an issue. I cut the legs short on the caps that go on the expansion board then bent the legs into a "L" shape and soldered them on.

I used Nichicon audio caps on the expansion board except on C604 and C610. I used ceramics in those two spots.

I use this to measure stuff when working on these consoles:

[thesteve]

i use ceramics for most of them and clearance is not a problem

[SegaSonic91]

Here are some pics of the area on my Super CD-Rom 2 unit.




The way the expansion board is laid out the caps are just behind the other ones on the main PCB. There is one cap in that area on the bottom at C63? but I used a ceramic cap in that spot so clearance was not an issue. I cut the legs short on the caps that go on the expansion board then bent the legs into a "L" shape and soldered them on.

I used Nichicon audio caps on the expansion board except on C604 and C610. I used ceramics in those two spots.

Nice!  Thanks for the pics.  Does not seem so bad now, and if I cannot get caps to fit, I know that ceramics are fine.

[pnauts]

I don't understand why people don't use SMD electrolytic Cap with same footprint as original, make it simple dude !

[blueraven]

if the laser just moves up and down check the tracks to make sure that the grease hasn't dried up. I would replace the laser if the problem continues past changing the caps. I had the exact same problem with A SCDROM2 a few years ago.

Ceramics are a lot better than you're giving them credit. They don't leak, and give you a lot more space on the inside if you're doing any modding.

[schweaty]

Gents,

whats the value of this cap in the pic?  you can see the pads in the pic, but its not on the chart.  thanks!

-dan

[BlueBMW]

I believe in the units I've worked on that cap location was left empty.

[schweaty]

I believe in the units I've worked on that cap location was left empty.

ok... i couldnt remember if i pulled a cap there or not.  i seem to remember the last time i did one of these a couple of years ago, there was a cap there and i noted the value because it wasnt on the chart.  i could be misremembering tho.

[thesteve]

It's 100µF
Half won't run without it

[schweaty]

It's 100µF
Half won't run without it

i can confirm this.  i put the cap in and my CD player started working.  should probably add it to the charts

so, the problem now is it will start most (but not all) games but will usually quit spinning at some point in the game after a run button or some other button is pressed.  is this a pot adjustment issue?

[SamIAm]

Image is down due to Photobucket being terrible.

[SmokeMonster]

Thanks for reposting, SamIAm. I have a SCDR2 coming and this will be handy for its obligatory recap.

[BlueBMW]

I need to go back through all my photobucket stuff and relocate things... sigh

[SmokeMonster]

If that missing cap isn't present, should it be added there regardless? Also, is the PCB marked with +/- for that cap's position? I don't have my SCDR2 in yet or I could answer that myself.

Also, does anyone have a list the caps that can safely be replaced with ceramics?

[NichlasEk]

If its not there i wouldnt add it. The board is marked + and withe for negative. Regarding the electrolytes vs ceramics, it would depend on who you ask. Some say stick with the original plan. Some say use electrolytics for the audio section.

I say use what you have at hand


*nevet mind, found a picture on the forum and got it working* getting a new oscope next week. Then i can calibrate for real!

[SmokeMonster]

If its not there i wouldnt add it. The board is marked + and withe for negative.

Thanks! thesteve confirmed to me that if the 100µF cap is not present, it should not be added. He also recommends using ceramics for everything but the audio section.

Could someone please identify which caps are part of the audio circuit?

[NightWolve]

If it's not there I wouldn't add it. The board is marked + and withe for negative.

Thanks! thesteve confirmed to me that if the 100µF cap is not present, it should not be added. He also recommends using ceramics for everything but the audio section.

Could someone please identify which caps are part of the audio circuit ?

I tried all ceramics on my SNES, but the pitfall was the Composite/S-Video amplifier/output circuit...

SNES engineers used 2 x 100µF capacitors in parallel to achieve 200µF before the signal leaves for the TV and replacing that area with ceramics led to disastrous results: white screens would lose sync, weird artifacts, just didn't work right...

Long story short I had to switch back to regular electrolytic caps for those video circuits, I just used standard 220µF caps so I wouldn't need 4.

Steve did consider the 4 100µF ceramics I used as defective from the factory because my DMM with capacitance measuring rated them at 60µF, but I don't think that was the only problem...

Kinda didn't trust the large ceramics after that, the small ones under 10µF are usually accurate in reflecting their labeled value. Electrolytic caps are usually higher than what the label says by default and lose said value over time as heats dries the fluid or it leaks out.