PROGRESS on CD-ROM² Repair

[wolfman]

PROGRESS!

Well, I´ve played again with it for a few hours. I finally found a broken solder spot on one of the BA6290s and right after that the sled moved again.

After a little bit of fiddling with the pots I got stable audio (though with a cracking noise in it). It would play the first 3 tracks, then it would cut out after trying to find the next track. With another CD it was even better, though it wouldnt play until the end. Inbetween I occasionally get a cracking/random noise, which I cant complete remove by adjusting the pots...

But with all progress made I can´t get it to read Game CDs for some reason. It would try a few seconds, then it cuts out. What could I do?

[thesteve]

Any crackle will cause data errors preventing game load
If everything is moving smoothly its either pots or laser 2

[wolfman]

Any crackle will cause data errors preventing game load
If everything is moving smoothly its either pots or laser 2

It is moving smoothly when playing music, though progressivly more cracking in sound (not drive itself!) when the laser moves outward on later tracks.

[thesteve]

that sounds like pot adjustments to me

[wolfman]

that sounds like pot adjustments to me

Trouble is, I´ve played around more than 2 hours with the pots, to no avail. Best I get is sound playing, but with crackling noise in it. On the other drive I adjust it within 15 mins....

Any other issue that might prevent a good setup?

[turbokon]

This is why I hate messing with the cd-rom2 unit.

[wolfman]

This is why I hate messing with the cd-rom2 unit.

Yes, I get your point. But what can I say.....I fell in love with the interchangeability of components... 

[thesteve]

Have you tried a slight adjustment of the pot on the laser 2

[wolfman]

Have you tried a slight adjustment of the pot on the laser 2

laser is brand new

[thesteve]

Sadly, it doesn't matter
I've had to adjust more new then old 2

[wolfman]

Sadly, it doesn't matter
I've had to adjust more new then old 2

Ok, so you mean turning down laser power partly resolves that?

[thesteve]

Often on a new laser turning it down helps allot
Especially with cdr
Duo laser cw increase
Cdr2 ccw increase 2

[wolfman]

Y I I P P I I  -  K  -  Y A A A A A A A Y Y Y Y Y Y    ! ! ! ! ! ! ! ! ! ! ! !

I´ve got a working drive now! After fiddling around for 14 days I finally made it. Man, it feels great to have done yourself. Can´t say how proud I am...      

Low  loading times, and so far no cutout of music/video. No sound issues. No weird sounds from the drive during loading except for chop´s louder gear.

I would like to thank the following members for their help and support in getting me thus far:

Keith Courage
thesteve
fidde_se
BlueBMW
deubeul

Without you I wouldn´t have made it, at least not within that short timespan...I really appreciate the help and knowledge on this forum!

There are however still 2 issues left:

1. Sled is still moving outwards after spindle shuts down or PCE gets rebooted, or when the drive gets power thru the plug.

2. The two BA6290 and the area on the PCB surrounding them gets VERY HOT. I almost burned my finger, when I touched the solder spots. On my other drive they stay rather cool....


Any clue how I could solve the last 2 problems? I am really really happy that the drive is working now, but I don´t want it to take damage again, so getting it to run reliable without acquiring a new "virus" would be very cool.

[thesteve]

They are the same prob
The ba chips are simple audio amps
They work like op-amps
Each chip has 2 bridged amps in it
They drive the lens 2 ways, spindle and sled (4 channels)
Each having a + and - input
If + = - all stop 2

[wolfman]

They are the same prob
The ba chips are simple audio amps
They work like op-amps
Each chip has 2 bridged amps in it
They drive the lens 2 ways, spindle and sled (4 channels)
Each having a + and - input
If + = - all stop 2

I lost you on the last line...what does "+ = -" have to do with overheating? Since they are soldered in both the way front to back + pretty close to each other - what could I do? Polarity is correct...

[thesteve]

its an op-amp
it uses balanced inputs
it gets hot because its not shutting off completely
each amp has 2 inputs known as +in and -in (not power)
when they match the output is off

[BlueBMW]

Look up the datasheet for those BA chips and find out which pins are the + input and - input and check them with a meter.  In other words, you should get some negative voltage on one pin and the opposite positive on another.  The data sheet should show which pins are linked together.  As steve said there are two inputs and one output pin for each amp.  If for some reason you get say +5v on one input and 0V on the other input pin then you know the problem lies somewhere in the - input circuit.

Make any sense or did I just make it worse...

[thesteve]

actually these amps have 2 output pins per amp

[wolfman]

Look up the datasheet for those BA chips and find out which pins are the + input and - input and check them with a meter.  In other words, you should get some negative voltage on one pin and the opposite positive on another.  The data sheet should show which pins are linked together.  As steve said there are two inputs and one output pin for each amp.  If for some reason you get say +5v on one input and 0V on the other input pin then you know the problem lies somewhere in the - input circuit.

Make any sense or did I just make it worse...

Does completely make sense. But I am not sure why they should be the problem - I have replaced the old ones with brand new ones....

[wolfman]

actually these amps have 2 output pins per amp

Here´s the datasheet:

http://www.datasheetcatalog.com/datasheets_pdf/B/A/6/2/BA6290A.shtml

I don´t get much out of it as it is unfortunately almost completely japanese....
Are we talking about pin 1, 6 and 12? I have measured 1 + 6 (+) vs 12 (-). They don´t show negative voltage.
Or am I wrong and it is 2 +3 (both +) and 10 + 11 (both +) vs 12?

EDIT: Ok I got it wrong. Pins 4+5 (In) and 2+3 are the outputs respectively. Same is Pins 8+9 (In) and outputs for them are 10+11. Right?

How would I measure - say, between 2 + 5 and 3 +4? Or between 4+5 and 2+3?

[thesteve]

Pin 6 is ref voltage
Look at the application schematic
It shows the required resistors
Outputs 2,3 are inputs 5,6
Outputs 10,11 are inputs 8,6
So if pin5 = pin6 pins2 and 3 will be the same voltage 2

[wolfman]

Pin 6 is ref voltage
Look at the application schematic
It shows the required resistors
Outputs 2,3 are inputs 5,6
Outputs 10,11 are inputs 8,6
So if pin5 = pin6 pins2 and 3 will be the same voltage 2

Ok, thanks for the guidance! What if they don´t match...where would I have to look for or what I could do to solve this issue? All resistors around measure fine and aren´t broken.

The only thing is my VOM cant measure the two caps between  the BA6290...I don´t get reliable results back (even if I try my other drive...).

[thesteve]

thats not an issue
find the output that isnt resting (shown with coil load on usage schematic)
meter across the pins shown hooked to a coil
check all 4 output sets before proceeding
if just 1 set is active, trace its input pin back
if both sets on a chip are active its likely a reference issue

[wolfman]

thats not an issue
find the output that isnt resting (shown with coil load on usage schematic)
meter across the pins shown hooked to a coil
check all 4 output sets before proceeding
if just 1 set is active, trace its input pin back
if both sets on a chip are active its likely a reference issue

Ok, here is what I did:

-Put the drive upside down, with the bottom open.
-Switched it to "Play", drive spun up, then lost focus and spindle stopped. Then drive moves sled 2-4 teeth to check for inner position (you can hear the gear for a brief moment then). It never spins up, just keeps searching for disc/focus. Sled wouldn´t move to outer position at any time.
-At that point I started measuring:

Since there are 2 BAs, I´ll give you the position of resistors so that you can locate the points:

At resistor position R146
Between 2 and 3: Voltage varied from -1.5 to +1.5 (probably during inner pos/foc check, since it moved on the VOM shortly after that sound I mentioned)

At resistor position R145
Between 5 and 6: Voltage 0

At resistor position R150
Between 6 and 8: Voltage 0

At resistor position R134-R136
Between 10 and 11: Voltage stable 0

At Capacitor C138:
Between 2 and 3: Voltage stable at 0.03

At resistor position R143
Between 5 and 6: Voltage shortly around 0.15, then 0

At resistor position R142
Between 6 and 8: Voltage shortly around 0.15, then 0, faint noise when touching with VOM tips (sounds like from a coil - laser coil?)

At Capacitor C137:
Between 10 and 11: Voltage stable at  0.15

Positive Pole from VOM was always on the lower Pin number (ie 2, 10), neg on the higher (ie 3, 11).

Does that tell you anything?

I´d like to add that apart from the sled issue this drive is working very very good - it has absolutely low loading times (even on CDRs, though losing audio at times) - eg Shapeshifter (original) starts up after ca 15 sec and levels load fast during gameplay. I really would like to get it stable....

[thesteve]

So it didn't have the issue while testing? 2

[wolfman]

So it didn't have the issue while testing? 2

No, the heat/sled issue is still unsolved. Strangely loading times seem not to be affected.

[thesteve]

Check connection between pin6 both chips
Your .15 output reading was wrong
The coil noise when touching with probe indicated high resistance (possible open)
 2

[wolfman]

Check connection between pin6 both chips
Your .15 output reading was wrong 2

Between what?

I confirm .15 WAS correct, I checked 3 times. Had it been 0 I would have said so. You think my VOM is glitchy?

[thesteve]

no i think your issue was producing 0.15
it should have been 0 but it wasnt
the same chip had an offset 0.06 on its other output as well so i suspect its pin6 isnt connecting solidly to the cxa1082 or has a resistor prob related to that chip

[wolfman]

no i think your issue was producing 0.15
it should have been 0 but it wasnt
the same chip had an offset 0.06 on its other output as well so i suspect its pin6 isnt connecting solidly to the cxa1082 or has a resistor prob related to that chip

Ok, thank you for verifying that. I´ll check for this...hopefully I´ll find something...

[wolfman]

Ok, I checked again all connections around the 2 BA6290s, everything had connection (lower PCB side).

On the upper side I verified all resistors I could access without desoldering items. Every resistor had matching numbers within tolerances. All connections to the CXA1082BQ seemed fine (the ones that I could check a little below and above pin #20, the others arent really accessible), connection between resistors and CXA also are fine.

I don´t know where else to look for...maybe a cap that has gone bad (although I replaced them first before I did anything else)?

There are two E474 SMD caps, where I don´t get results with my VOM...from the number I´d say it they are 16V/470uF?

[thesteve]

Might be 0.47uf 2

[wolfman]

Might be 0.47uf 2

Do you think it could be responsible for this issue?

[thesteve]

Nope
 2

[wolfman]

Ok. Since I can´t find the source of this error and the drive is working fine except for the heat issue, I´ll leave it the way it is. At least it is working and is reading every CD fine....guess I should be happy anway.

Thank you though for your support!

[pnauts]

Hi guys, I use this topic to avoid opening another one. I decided to bring back to life a dead  CDR² unit. I know mine had a middle gear issue, and send my regards to PC Kid from the French forum dedicated to NEC consoles, who provided me a new gear, that he made with a supplier he know. The easy part with the old one is it turn into dust very quickly with age.


_{https://i.postimg.cc/9XspDhTX/DSC-0891.jpg}



Once done, I removed the little plastic chips stuck in the grease, check the complete rotation of the new gear and I used a original game and I did face to the "Wait a Moment" issue.

Ok so the CD spin it's a good point, but I decided to test first an audio CD, TesseracT - Altered State 432hz, tracks are detected quickly then only scratching noise when attempting to read then stop quickly. I decided to adjust directly last pots while reading.
For that I removed the bottom case, put down an isolation paper to avoid short and give it a try on VR105.

the audio came back and the reading seems smoothy with less mechanical noises.
I did try a CD game (Spriggan) with success but I encountered some issues with SCD.
With Deden no Den I had Macroblocking picture right after launching the game and with Emerald Dragon green screen.

I think I'm not too far from fixing it, and I think perhaps I'll have to check again the VR105 (Voltage control oscillator, right ?) I can have an oscilloscope for testing RF pin, so any screen example will be appreciated.
Thanks.

[pnauts]

fixed.
super system card on Everdrive + SCD + CDromrom = don't works.