PROGRESS on CD-ROM² Repair

[wolfman]

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

Sent from my ADR6300 using Tapatalk 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

Sent from my ADR6300 using Tapatalk 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

Sent from my ADR6300 using Tapatalk 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

Sent from my ADR6300 using Tapatalk 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

Sent from my ADR6300 using Tapatalk 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

Sent from my ADR6300 using Tapatalk 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 referance 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 referance issue

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 referance 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?

Sent from my ADR6300 using Tapatalk 2