OK, Here Is A LONG Shot, But....

E

EADGBE

Guest
.....Does anyone know where I can download the schematic for an Audio
Alchemy CD player?

The model is a Digital Drive System II (also known as a DDSII).

Many thanks in advance.....
 
On Jul 25, 7:27 am, EADGBE <hwbossh...@comcast.net> wrote:
....Does anyone know where I can download the schematic for an Audio
Alchemy CD player?

The model is a Digital Drive System II (also known as a DDSII).

Many thanks in advance.....
Click to expand...
You're right, long shot. Very long shot.
 
On Jul 25, 12:05 pm, "Arny Krueger" <ar...@hotpop.com> wrote:
Why bother fixing it?
Click to expand...
I got it for free; it seems like a (fairly) nice CD player; just
curious about the sound.

I really don't know if I actually need the schematic. I'm pretty sure
it's a bad op-amp. The CD spindle motor won't activate, even though
the motor tests fine and so do the transistors responsible for
supplying the motor voltage.

It's just something to tinker with on a rainy afternoon, that's
all......
 
Arfa:

Thanks for the helpful information.

All I know at this stage is that the CD will not spin under any
condition...HOWEVER, when you turn the power off, the CD will spin
maybe a quarter of a turn while the unit is powering down.

And here's a strange fact: The other day I started messing with the
player after having it sit for a couple of weeks. I switched it on
and inserted a disc. Quite unexpectedly, it spun the disc and the
disc's track information appeared in the digital readout window!

At that point I should have pressed "play" to see what would happen,
but I ejected the disc and re-inserted it. Back to square one--the
disc didn't move.

This has been the one and only time the player has ever spun a disc
since I acquired it.

I have measured the voltage coming off of the four-transistor bridge.
Whenever a disc is inserted, the necessary 5 volts appears for a MICRO-
second, and then the voltage goes back to zero.
 
EADGBE <hwbosshoss@comcast.net> writes:

Arfa:

Thanks for the helpful information.

All I know at this stage is that the CD will not spin under any
condition...HOWEVER, when you turn the power off, the CD will spin
maybe a quarter of a turn while the unit is powering down.

And here's a strange fact: The other day I started messing with the
player after having it sit for a couple of weeks. I switched it on
and inserted a disc. Quite unexpectedly, it spun the disc and the
disc's track information appeared in the digital readout window!

At that point I should have pressed "play" to see what would happen,
but I ejected the disc and re-inserted it. Back to square one--the
disc didn't move.

This has been the one and only time the player has ever spun a disc
since I acquired it.

I have measured the voltage coming off of the four-transistor bridge.
Whenever a disc is inserted, the necessary 5 volts appears for a MICRO-
second, and then the voltage goes back to zero.
Click to expand...
Respectfully, you emailed me first about this player. I assumed you
had actualy looked in the CD repair FAQ. Apparently, that wasn't the case.
Instead of taking up everyone's time answering basic questions, please
go to the "startup problems" sections there and attempt to determine
exactly what it is or is not doing. Then, everyone can be of more
help.

http://www.repairfaq.org/sam/cdfaq.htm#cdsup

As has been noted by others, the spindle motor failing to spin is almost
never a problem with the motor or its immediate driving electronics, but
rather with the optical pickup not getting focus lock due to any number
of causes. With your erratic behavior it could even be a something
mundane like a bad flex cable. And, it could still be a dirty lens.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
 
On Jul 26, 7:06 pm, Sam Goldwasser <s...@minus.seas.upenn.edu> wrote:
Respectfully, you emailed me first about this player.  I assumed you
had actualy looked in the CD repair FAQ.  Apparently, that wasn't the case.
Click to expand...

Hi, Sam:

I really apologize, but I don't think I e-mailed you about this
player. Unless I am having a severe case of amnesia, my original post
here is the first time I have discussed this player online. I did
have a question about a Yamaha player a couple of months ago, but that
issue has been resolved.

If I did indeed e-mail you about this player, please accept my
apologies. I will consult the CD repair FAQ as you have directed.
 
EADGBE <hwbosshoss@comcast.net> writes:

On Jul 26, 7:06 pm, Sam Goldwasser <s...@minus.seas.upenn.edu> wrote:

Respectfully, you emailed me first about this player.  I assumed you
had actualy looked in the CD repair FAQ.  Apparently, that wasn't the case.


Hi, Sam:

I really apologize, but I don't think I e-mailed you about this
player. Unless I am having a severe case of amnesia, my original post
here is the first time I have discussed this player online. I did
have a question about a Yamaha player a couple of months ago, but that
issue has been resolved.

If I did indeed e-mail you about this player, please accept my
apologies. I will consult the CD repair FAQ as you have directed.
Click to expand...
My apologies. It was someone else. Probably the "long shot" part
made me think it was you. :)

Anyhow, do read the CD repair FAQ and then you can post your findings.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
 
EADGBE <hwbosshoss@comcast.net> writes:

I have looked at the CD repair FAQ (very informative!), and I have
done the following:

1. I have cleaned the lens with isopropyl alcohol.

2. I have discovered that the laser pickup WILL NOT re-center itself
under any condition if I manually move it away from the motor spindle.
Click to expand...
This may be the main problem. This is usually done regardless of the
state of the laser pickup. So, either the sensor isn't working or
there is a problem with the motor driver.

3. As far as I can tell by simple observation, the laser pickup DOES
NOT light up under any condition. (I looked at the lens from an
oblique angle about 6 inches away from it in a darkened room.)
Click to expand...
So, not even a tiny red dot?

Did you reset the sled to the center? It might not light up if the
sensor thinks it's starting at the wrong place.

Else, there is a problem with turning on the laser. You did say it
recognized the ToC once, right? So the laser itself works.

Could be a bad connection/bad cable.

4. I have verified that the lens drive motor AND the CD spindle motor
do work OK. (I unplugged each motor's wiring harness and applied a
small DC voltage.)

5. I have cleaned the contacts on the little leaf switch that opens
and closes whenever the CD drawer opens and closes and verified that
the switch is opening and closing normally.

6. I have verified that all wiring harness connectors are clean and
well-seated.

Somehow, this player simply will not turn the CD playing circuits on
when the drawer closes. I think the logic IC is fried. Oh well, I
needed a few electronic parts, so now I have a whole box full!
Click to expand...
Doubt it. :) Certainly possible, but the most complex most expensive
part really isn't likely to be bad.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
> Thanks to everyone for your help....
 
I have looked at the CD repair FAQ (very informative!), and I have
done the following:

1. I have cleaned the lens with isopropyl alcohol.

2. I have discovered that the laser pickup WILL NOT re-center itself
under any condition if I manually move it away from the motor spindle.

3. As far as I can tell by simple observation, the laser pickup DOES
NOT light up under any condition. (I looked at the lens from an
oblique angle about 6 inches away from it in a darkened room.)

4. I have verified that the lens drive motor AND the CD spindle motor
do work OK. (I unplugged each motor's wiring harness and applied a
small DC voltage.)

5. I have cleaned the contacts on the little leaf switch that opens
and closes whenever the CD drawer opens and closes and verified that
the switch is opening and closing normally.

6. I have verified that all wiring harness connectors are clean and
well-seated.

Somehow, this player simply will not turn the CD playing circuits on
when the drawer closes. I think the logic IC is fried. Oh well, I
needed a few electronic parts, so now I have a whole box full!

Thanks to everyone for your help....
 
Arfa:

You hit the nail on the head. The problem appears to be related to
the power supply...or at least to a component downstream from the
power supply.

Right next to the connector that leads to the laser assembly, one of
the contacts is labeled "5V". Measuring this contact gives me less
than half a volt under all circumstances.

This 5V contact leads directly to the collector of a 2SA1270
transistor. The transistor checks out OK, although the same half a
volt reading is measured at the collector. There is a jumper wire
that leads to the emitter of this same transistor. It is also clearly
labeled "5V", and it measures a healthy 5.08V.

The base of this transistor is connected, via a 10k resistor, to the
middle lead of a very small transistor with "C114" on the case. If it
is a 2SC114, I cannot readily find a replacement for this transistor,
and I cannot find a datasheet, either, so I don't know how to check
this transistor. It gives me weird readings whenever I test it in
standard NPN or PNP pin configurations. IT DOES NOT SEEM TO BE
DEFECTIVE, HOWEVER, because there are several "C114" transistors and
they all give me extremely similar readings whenever I attempt to
measure them in standard NPN and PNP pin configurations. There are
also a couple of 100uF/16V electrolytics in this circuit used as
couplings to ground, but they check out fine with my ESR meter and my
analog ohmmeter.

I am going to attempt to keep checking upstream to see where things
break down.
 
Arfa:

Are you saying that I should suspect the DTC114 or the 2SA1270? Or
something else?

I'm betting on the DTC114 being the culprit.
 
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