Philips CD207 CD player over-revving?
losinj
I've just unearthed my vintage CD207 player from the loft, which is
where it's been stored for years since it went faulty, preparing to
chuck it out. To my surprise, it worked - for a few days, anyway. Now
it is faulty again, so the problem seems to be intermittent - a dry
joint maybe.
The audio sounds fine. The problem seems to be with the motor drive.
This revs up a couple of times when first switched on (its normal
behaviour), but then runs continuously instead of stopping. If a disc
is mounted first, it will spin out of control.
I read an earlier post about a CD207 owner having problems with dry
joints. Although I have a service manual for the player, and can wield
a soldering iron, if I am looking for a dry joint I don't really know
where to start looking, and could do with some guidance. Can anyone
help me out, please?
Jerry G.
solder connections, as of many of them can cause your unit to not work.
Proper troubleshooting would be necessary to service your init.
The first thing to look for are visual faults, such as visible cold
solder connections, and or broken parts, burned parts, or bad
connections.
The next step is to verify that all the power supply outputs to the
various areas on the boards are working properly.
The final step would mean following it through with a DVM, and a
scope, to follow through the signal processing.
Jerry G.
======
ZZa...@aol.com
losinj
the aid of an watchmaker's eyepiece, and resoldered a few that looked a
bit suspect (I couldn't tell you which ones though). Thankfully, the
player is now working again, so maybe that was the problem.
Franc Zabkar
finger to keyboard and composed:
>Hi.
>I've just unearthed my vintage CD207 player from the loft, which is
>where it's been stored for years since it went faulty, preparing to
>chuck it out. To my surprise, it worked - for a few days, anyway. Now
>it is faulty again, so the problem seems to be intermittent - a dry
>joint maybe.
>The audio sounds fine. The problem seems to be with the motor drive.
>This revs up a couple of times when first switched on (its normal
>behaviour), but then runs continuously instead of stopping. If a disc
>is mounted first, it will spin out of control.
>I read an earlier post about a CD207 owner having problems with dry
>joints.
The very early Philips/Marantz players had double-sided PCBs. A common
problem was dry joints at the thru-holes, especially those connected
to the ground planes. IIRC, the motor could even spin backwards when
these faults were present. The most reliable fix, as implemented in
later models, was to fit pins to each hole.
- Franc Zabkar
--
Please remove one 's' from my address when replying by email.
Steven
news:hrkp31djudd1j2lek...@4ax.com...
Have you considered that the disc might not be clamping properly, or do you
have the drive opened to where you can observe it's operation? Improper
clamping will often result in severe, irrecoverable disc wobble, which in
the case of some players can be corrected through readjustment of the arm
assembly, along with a great deal of trial and error tweaking. I have used
this method successfully on a few players I.e. NEC CD-510 IIRC which is
similar to some late 80s Sony models I've owned. If you can believe the disc
actually running BACKWARDS from the friction of the poor contact, you can
believe a lot of things, I suppose.
Good luck in your repair efforts!
Franc Zabkar
to keyboard and composed:
>"Franc Zabkar" <fza...@optussnet.com.au> wrote in message
>news:hrkp31djudd1j2lek...@4ax.com...
>> The very early Philips/Marantz players had double-sided PCBs. A common
>> problem was dry joints at the thru-holes, especially those connected
>> to the ground planes. IIRC, the motor could even spin backwards when
>> these faults were present. The most reliable fix, as implemented in
>> later models, was to fit pins to each hole.
>
>Have you considered that the disc might not be clamping properly, or do you
>have the drive opened to where you can observe it's operation? Improper
>clamping will often result in severe, irrecoverable disc wobble, which in
>the case of some players can be corrected through readjustment of the arm
>assembly, along with a great deal of trial and error tweaking. I have used
>this method successfully on a few players I.e. NEC CD-510 IIRC which is
>similar to some late 80s Sony models I've owned. If you can believe the disc
>actually running BACKWARDS from the friction of the poor contact, you can
>believe a lot of things, I suppose.
>
>Good luck in your repair efforts!
I'm not the one having problems. In any case, *my* Philips/Marantz
player *did* spin backwards, and it *was* due to dry joints in the
earth connections between the top and bottom sides of the PCB. Believe
me, you don't forget something like that. In fact I confirmed the open
circuit(s) with a DMM.
I now have a Philips CD104 (aka Marantz CD44A) CD player which has the
same type of PCBs, but which has pins in each thru-hole. The turntable
motor control circuit consists of an MC1458 dual opamp (+/-12V
supplies) and a push-pull NPN-PNP transistor pair (+5V & -6V
supplies). One end of the motor is grounded, the other is connected to
the push-pull emitters. With this kind of circuit it is quite possible
for the motor to spin backwards in the event of a logic failure.