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

[BlueBMW]

It seems that none of this hardware is safe from leaking capacitors as some of these Super CD-ROM² units have started to exhibit issues relating to failing capacitors.  Note that both RF shields must be removed and the laser assembly must be removed before all the capacitors can be accessed. Below is a chart mapping all the capacitors in the Super CD-ROM² unit.

The laser installed in the Super CD-ROM² is the Sony KSS-210B and the unit has the same 5 adjustment pots like a Duo unit.

UPDATE:

Some units have an additional 100µF cap installed right above the 4 sided Sony chip next to the 22µF surface mount caps beneath the laser assembly.  Others just have an empty pad without a cap.

Also, the RF shields MUST be reinstalled for this unit to work properly.  It looks like it links some grounds to one another.



Thanks once again to Red Ghost for the chart format!

[chop5]

nice clear pictures!

[NecroPhile]

Nice, bimmer.  Give this man a sticky!

[Platinumfungi]

Nice work! Yet another great resource for the community. Thanks for crediting my layout design too 

[BlueBMW]

Nice work! Yet another great resource for the community. Thanks for crediting my layout design too 

Hey! Credit where credit is due!   And by keeping the same format across all systems, it makes it easier to reference.

[Platinumfungi]

Nice work! Yet another great resource for the community. Thanks for crediting my layout design too  

Hey! Credit where credit is due!  And by keeping the same format across all systems, it makes it easier to reference.

Agreed! This needs to be a sticky as well. I'm going to try and go find where I put in requests in the past...

EDIT: Ok, just found the old "Sticky request" thread over in the "Comments and Suggestions" forums and requested both this topic and the other old TGCD repair topic I made be made "sticky"

[PCEngineHell]

Curious, on the current cap repairs, have you guys switched over to using surface mount solid caps, or are you still using the normal thru-hole electrolytic stuff? Solid caps have come down in price the past few years, to the point even that they are becoming a normal for even midrange pc motherboards. You guys may want to look into bulk buying them, at least the smaller ones, so you can solder them on their required spot instead of having to run wires out and stuff to work around the tight fits.

[BlueBMW]

I still use leaded caps because I'm not that good at SMT stuff yet, though as I get better I'll probably switch over to direct replacement caps.

[pixeljunkie]

what's the easiest/cheapest way to get all the caps necessary for this job?

Also, is there a cluster that are for the sound, if I want to only replace those?

[BlueBMW]

The cheapest way is to buy caps in bulk which doesn't work well if you're just doing one system.  Ill be putting an order in for more caps soon so pm me if you'd like me to get you a set.

As far as just doing sound caps... there's really no point in doing only some of the caps.  They're all the same age and likely leaking.  Just because a cap doesn't affect sound doesn't mean it wont affect another system.  I've had bad caps cause laser read issues before.  If you're already in there just do them all.

[PCEngineHell]

Yeah, honestly the cheapest way would be for you all to pull your resources into a group purchase if you can get at least 6 or more people in on it, that should go to one guy who will serve as the capacitor bank. Buy enough to handle 20-30 systems minimum. Then as you all need the caps, he can mail them via first class mail out to you in the bundles you need that you paid for, and sell bundles to others too, and use that money towards refilling the bank when it gets near empty.

[BlueBMW]

I buy between 50 and 250 of each size cap each time I order them.

[farankoshan]

I'm pretty interested to get a full set of replacement caps for an ailing unit. Would you have some on hand? Please PM me if you do, or when you'd next be ordering some.

Can you find these at local hardware stores around the world?

I have some capacitor vendors around here in my area.
When searching for caps, what type of caps should I use, and which not to use?

eg.
Type/Make: Radial caps, Aluminum, electrolytic? Which to avoid?
Mounting: Through hole or Surface mount?
Capacitance Value: (These values I already have via BlueBMW's very helpful guide.)
Tolerance: ?
Voltage: (Also from Blue BMW)
Ripple Current: ?mA

Thanks so far guys!

[farankoshan]

I appreciate all the help guys!

[farankoshan]

I replaced all the caps I was able to source locally at a electric hardware store around here.
The sound problem I had initially remained during the first try, but cleared up in about 5 mins (it used to take close to 20 mins with the old caps). Will observe some more if the problems remain. Thanks, for the help guys!

See this other thread for an update on my problem:
https://www.pcengine-fx.com/forums/index.php?topic=10214.0

[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.




cimg6327f.jpg
cimg6322.jpg

[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 symptom is got low volume/ static sound from the Super CDROM AV port int he first few minutes. 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

[thesteve]

I actually solved this issue recently
The problem, was a dirty main board, near the 1000µF cap

[choijimmy]

I actually solved this issue recently
The problem, was a dirty main board, near the 1000µF cap

Thanks thsteve.

I did cleanup the board with alcohol / contact cleaner yesterday but No luck. Not sure why. Also, I don't see any leak residue close to 1000uf.

Indeed, I have 2nd Super CDROM which complete No sound for CD game ( but HuCard is good ). Let me try to clean that board thoroughly to see it helps or not.

Thanks again!
Jimmy

[thesteve]

When I found it I couldn't see anything on the board either as another tech had cleaned it
On the 7pin plug of the sound board the center pin is antithump
It must be 0 when running
It runs near a power trace under the board, and any residue pulls the voltage up

[BlueBMW]

Very good info to know there steve!   I've seen several super cdrom2s with this issue.

[pnauts]

Hi all, I'm trying to solve a SCDR² issue with very low sound (no crackles), I just try with Hucard (mono) for the moment. I started to draw a scheme for the small upper board (4558 is a 2 x amplifiers, BU4053BF is an analog mux/demux, M51131L is the volume/balance control).

I checked all electrolytic capacitors of this upper board with the capacimeter function of my Multimeter, the values are in the specs of the nominal values.
Is it a capacitor with good measured value could be defective ?

On the other side of the board, I checked the diodes in the transistors Q601/Q602/Q603/Q604, and the 2 x diodes with common anode from D601 are ok too.
I cleared the solder flux.
The supply on the CN103 connector between pins 6 (9V according to my memory) and 6 (gnd) seems ok, I thought initially it would be around 12V, if someone can confirm me ?
outputs audio signals are routed to 1 & 3 of CN103.
The voltage for volume control (from CN104 pin 4) seems at correct level (5V).
When I will investigate enough on this one I'll have a look on the audio section on the mainboard.

[BlueBMW]

I seem to remember Kieth Courage finding another issue on these units that caused low volume but I cant remember what it was... hopefully he will chime in here soon.

[pnauts]

He did strap a resistor on the transistor base, not the right solution imo.
on the pin4 of the 7 pin connector (on top or bottom board), anyone can tell me where this pin goes?
it's the command on the base of the transistor (through a diode and a 1K resistor on each)

edit: Keith courage mods, pictures on last post previous page, but as Steeve pointed the mod adressed the symptoms, not the cause.

[pnauts]

here a little schema.



what is routed to the pin 4 and where ?
Is voltage on pin 6 correct ?

[pnauts]

here are the voltages I measured, 0V console to earth with oscilloscope probe, with a Hucard:

CN104(1): 4V (Z io of the BU4053B)
CN104(2): 0V (ABC bits selections of the BU4053B)
CN104(3) 4V (IC521 pin 3 & 5 in+ of amplifier 4558)
CN104(4): 5V (volume control input of M51131L)
CN104(5): 0V
CN104(6): 4V (1st out amp 4558 IC506)
CN104(7): 4V (2nd out amp 4558 IC506)
CN104(: 4V
CN104(9): 4V

CN103(1): audio Left not measured
CN103(2): 0V (ground)
CN103(3): audio right not measured
CN104(4): 1,32V (Q603 & Q604 base, before diode ans 1K resistors)
CN103(5): 4V
CN103(6): 8V (V supply, from pump charge ?? because no other regulator than 7805)
CN103(7): 4V

M51131L (volume & balance control)
1: 8V (V supply)
2: 3.4V (input 1)
3: 3.1V (output 1)
4: 5.52V (Vréf)
5: 8V (Low pass filter)
6: not connected
7: gnd
8: 5V (volume control)
9: gnd
10: 2.8V (Balance control)
11: gnd
12: 5.52V (wire to 4)
13: 3.1V (output 2)
14: 3.4V (input 2)

if someone can make measurement to compare to my values, thanks for your help

[thesteve]

cn103 pin 4 is wrong
the board needs cleaned better

[pnauts]

thanks.
Do you know where is routed the pin, I try but for the moment I did not succeed to find.
I suppose the voltage should be closer to 4V ?

[pnauts]

cn103 pin 4 is wrong
the board needs cleaned better

after better cleaning, it improved a bit the volume (but more cracklings), I checked the voltage on pin 4, the value is lower (around 0.9V), so I suppose the value should tend to 0V to increase again volume.
This pin is routed to D303 cathode (2 x diode, one is wired to the PNP Q309, the other to PNP Q308.
Base of Q309 is wired to Vout of expansion port through 10K (R311). Base of Q308 is wired to D304 anode through 6K8 (R319). Cathode of D304 is wired to 8V.
There is a common point on Q309 and Q309 wired to cathode of ZD303 (I suppose it's a zener).
I think be close to the solution...

[BlueBMW]

How are you cleaning the board?  I found that the only way to really get all the old leaked fluid out is a dishwasher run.

[pnauts]

I use a flux remover and a brush
something like this

[pnauts]

I use only Hucard for testing right now, CD unit is remove for the moment.
I think cracking come from capacitors, I will try to change some of the 10µF/16V (even if measured values are ok)

[thesteve]

it runs all over, but I've seen the issue under the board near the 1000µF cap

[thesteve]

The crackles are from that voltage

[pnauts]

from that voltage ? the 0.9V, what is yours on connector ?

here are an image of what I think is wired (except error) all discrete components are close each others I wrote the measured values.


https://postimg.cc/zbgkRqC0

when I use the DMM on the Q308 base, more crackling noises.
I think about a problem on Q308 ? what do you think ?
still dirty residue in your opinion ??

Thanks.

Edit: ok my pin is the one you talk above (antithump) that should be close to 0V ?

[thesteve]

my tests oc crackling units was 0.9-1.2
good was 0.0-0.15

[pnauts]

I'm pretty confident the issue is fixed, because I removed the 1000µF, there was capacitor's leakage, the varnish and the via was attacked.
I washed all and set a product to minimize contact resistance, and changed the capacitor.
For whom want to know, I answer to one of my question, yes a capacitor can have a good value but be defective.
I'll test tomorrow and keep you in touch.