aligning cd player heads

[Lyle]

sorry if this is too off topic but I'm about ready to toss my 13 month old
el cheapo desk top CD player because it won't read 75% of all disks. So
Before I do, does anyone have any suggestions on how to realign the heads?
I can see a pot on the reader arm, should I just twiddle, try, repeat or is
there more method?
thanks
Lyle

 

[Pooh Bear]

sorry if this is too off topic but I'm about ready to toss my 13 month old
el cheapo desk top CD player because it won't read 75% of all disks. So
Before I do, does anyone have any suggestions on how to realign the heads?
I can see a pot on the reader arm, should I just twiddle, try, repeat or is
there more method?

Assuming it's the *right* pot, anyone with a setup procedure would likely be
scoping a relevant part of the circuit.

I suspect there'll be servo pots ( probably elsewhere ) and maybe this is a
focus pot ?

If you're going to throw it anyway, there's no great loss fiddling with the
thing.

Graham

 

[Glenn Gundlach]

sorry if this is too off topic but I'm about ready to toss my 13 month old
el cheapo desk top CD player because it won't read 75% of all disks. So
Before I do, does anyone have any suggestions on how to realign the heads?
I can see a pot on the reader arm, should I just twiddle, try, repeat or is
there more method?
thanks
Lyle

So for laughs, I just opened my cheapy Panasonic with 'digital servo'.
It has 5 ICs on the 'transport' assembly, a display which is probably
the system controller also and a 4558 opamp on the main board. Not a
pot in sight.

As for your player, Graham's suggestion is as good as any. The issues
I've seen and read about usually have to do with dirty optics and/or
laser diodes that go bad. There are many surfaces that can get dirty
and can't be cleaned because they're in the optics block so the only
option is to replace it. For the price of cheapy players, if worst
comes to worst, just replace it.
GG

 

[Browser]

Haven't visited in a while, but last time I was there, www.repairfaq.org/sam
had a large section on CD repairs.
Dave McDonald
Johannesburg

 

[Paul Hovnanian P.E.]

So for laughs, I just opened my cheapy Panasonic with 'digital servo'.
It has 5 ICs on the 'transport' assembly, a display which is probably
the system controller also and a 4558 opamp on the main board. Not a
pot in sight.

As for your player, Graham's suggestion is as good as any. The issues
I've seen and read about usually have to do with dirty optics and/or
laser diodes that go bad. There are many surfaces that can get dirty
and can't be cleaned because they're in the optics block so the only
option is to replace it. For the price of cheapy players, if worst
comes to worst, just replace it.
GG

The other part that gets worse with age is the motor bearing and
spindle. If the disk develops too much wobble due to a bad bearing or
sloppy disk algnment, the tracking servos can't handle the error.

 

[Pooh Bear]

The other part that gets worse with age is the motor bearing and
spindle. If the disk develops too much wobble due to a bad bearing or
sloppy disk algnment, the tracking servos can't handle the error.

That'll be true for sure. Although some cheapies may be surprisingly reliable.

At a company I worked for they had a new swish phone system that played whatever we
put in a CD player to ppl on transfer.

My colleagues simply bought the cheapest unit they find in the local Dixons /
Currys ( a large UK retail chain dealing in what would once have been called
'brown goods' and 'white goods' ). It was a no brainer. It had to be on effectively
24/7 and if it failed in the 1 year guarantee period we'd get a free replacement !

It only cost about £50 anyway and easily outlasted its guarantee period. Now you
can buy a DVD player for less than that amount too !

Graham

 

[Pooh Bear]

So for laughs, I just opened my cheapy Panasonic with 'digital servo'.
It has 5 ICs on the 'transport' assembly, a display which is probably
the system controller also and a 4558 opamp on the main board. Not a
pot in sight.

A long time back a colleague and I opened up a misbehaving Sony CD player
belonging to a mate of his and our jaws dropped at the miniscule size of the pcbs
inside. Aside from the mechanism and display it was about 2 large SMD chips and a
PSU and some passives ! On single sided 'paper' boards too ! I think we cleaned
something and it started working again. Again a no-brainer. It wasn't worth
anything so tried mucking about to see if it makes it better.

As for your player, Graham's suggestion is as good as any. The issues
I've seen and read about usually have to do with dirty optics and/or
laser diodes that go bad. There are many surfaces that can get dirty
and can't be cleaned because they're in the optics block so the only
option is to replace it. For the price of cheapy players, if worst
comes to worst, just replace it.

I have a 'classic' CD player, a Denon DCD-1700. Won awards and stuff. It was the
first CD player I heard that 'sounded right' and given the engineering inside it
damn well should do ! One of the first to use oversampling for example. Unlike
the modern ones you can pick up with your little finger, this one is actually
*heavy* !

It's so beautifully made that when it started playing up I had it serviced by the
Uk distributor - fortunately nearby and an excellent company. Took it there and
collected it in person. Cost no more than a cheapie replacement to get everything
working fine again and it works fine still, about 15 ~ 16 yrs on from when it
was made.

Graham

 

[Lyle Walsh]

Holy smokes what a great site!!!! They even go into detail on methods to
resurect badly scratched CD's. I reccommend that everyone who likes to
tinker bookmark this site for future reference.
Thanks
Lyle

 

[Glenn Gundlach]

Holy smokes what a great site!!!! They even go into detail on methods to
resurect badly scratched CD's. I reccommend that everyone who likes to
tinker bookmark this site for future reference.
Thanks
Lyle

I had a scratched software CD from the lens hitting the disc and
thought it was ruined. Had it polished out for $3 at a game store.
Looks and plays like new.
GG

 

[Frithiof Andreas Jensen]

I can see a pot on the reader arm, should I just twiddle, try, repeat or is
there more method?

Put it up for sale in an auction and use the money to buy a new one -
Especially if it is a "Leading Brand Name"; some sucker is bound to pay 50%
of the cost of the unit in the shops. Then sucker will send it in for
service and everybody is happy.

---Unless---

The problem is Copy Protection in which case the unit just cannot play with
any of the modern, gabled, non-cd's pushed by the record companies. Then you
will have to get your stuff from off the net - Itunes or Bit-torrent - and
burn real CD's yourself. ;-)

 

[Rich Grise]

sorry if this is too off topic but I'm about ready to toss my 13 month old
el cheapo desk top CD player because it won't read 75% of all disks. So
Before I do, does anyone have any suggestions on how to realign the heads?
I can see a pot on the reader arm, should I just twiddle, try, repeat or is
there more method?
thanks
Lyle

How are your CD care and handling procedures? Are you letting your little
brother play frisbee with them? Are they all covered with finger grease
and/or chocolate? You can clean them with a soft, lint-free cloth and
Windex; but wipe in a circular motion - never wipe one crosswise.

Good Luck!
RIch

 

[Glenn Gundlach]

How are your CD care and handling procedures? Are you letting your little
brother play frisbee with them? Are they all covered with finger grease
and/or chocolate? You can clean them with a soft, lint-free cloth and
Windex; but wipe in a circular motion - never wipe one crosswise.

Good Luck!
RIch

That, Rich, is exactly the opposite of what I read many years ago. The
opinion at the time was that radial marks are easier for the error
correction to deal with. Circular marks can cause the servo to lock
onto the new 'track'.

The commercial disc buffer took ALL the marks out and restored my $70
Partition Magic disc. Cheap ($3) and highly recommended.

Personally, I clean discs with warm water and dish detergent and dry
with a terry cloth.
GG

 

[Rich Grise]

That, Rich, is exactly the opposite of what I read many years ago. The
opinion at the time was that radial marks are easier for the error
correction to deal with. Circular marks can cause the servo to lock
onto the new 'track'.

Hmmmmm... That might very well be what I heard, and disremembered; I
do remember it being about the scratches/streaks. But, heck, every time
I've got a 50-50 chance of getting it right, 90% of the time I get it
wrong. ;-)

The commercial disc buffer took ALL the marks out and restored my $70
Partition Magic disc. Cheap ($3) and highly recommended.

Personally, I clean discs with warm water and dish detergent and dry
with a terry cloth.
GG

Thanks!!
Rich