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CD player fault

My CD player Rotel RCD-02 similar to the european version RCD-961/RCD-971 is no longer playing compact discs.

The CD player has been placed above a class A amplifier which produces a lot of heat, and indeed in use the CD player base has gotten quite hot probably around 60-70 degress. I am thinking that the reason for the cd player failure is the laser diode may have prematurely failed due to extended periods of heating.

The optical block in the CD player is a Sony KSS-213C.

I have tested the ribbon connector between the optical block and the main circuit board with a DVM resistance meter and found no fault in the wiring. Additionally I have checked the PSU which is a good solid transformer type, this appears to be fine, although I have no reference to actually check this, but power is present.

I have removed the cd spindle clamp and observed with a mobile phone CCD camera which is sensitive to IR light that there is a blueish grill like pattern l(like a ||| shape) from the lens of the laser diode. This suggests there is power.

Additionally the CD player detects when a disc is present and not present. When the drawer is closed if a CD is there it will spin it up, if there isn't a CD present the motor spindle moves a bit then the player displays "No dISC".

When a CD is placed and drawer closed, the optical block will move to inside to read the TOC. If the optical block is displaced it will move back to the TOC smoothly so this mechanism apperas to be fine. The CD player will spin up a CD. The disc continues spinning but power is applied to the CD spindle motor to spin up the CD again and again, I assume this to get the correct speed as it attempts to focus and read the disc. The motor voltage is about a volt and peaks at about 2.3 volts though this is difficult to tell with a DVM. The CD player does not go further than this stage and keeps spining up the disc in an attempt to read it.

I noticed that with a Single CD with only 3 tracks on it, and 14 minutes total length, the CD player actually played track 1, but then stopped after the second track, since this brief moment of operation and before it has remained faulty though.

I am appealing for help as I have read about CD player faults but have no practical experience until now and I thought there may be more people with more knowledge. I am tempted to replace the optical pickup but am unsure whether this really is the fault. Any help will be much appreciated.

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subseb
Reply to
subseb
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Hi!

Does this CD player have any sort of a laser locking system on it? (Some players have either a set of screws and a sort of "slider bar" and others have a button that may be pressed to lock the laser pickup into place. This is done so the pickup doesn't slam around during transit.)

In the case of the button, there's always the possibility that while moving the player, someone pressed the button in and locked the laser. When this happens, most players will have an extreme amount of difficulty playing A) anything at all or B) much past track 1. Or, with the "slider bar" arrangement, there is always the possibility that the screws are out of it, thusly letting the bar move and causing the pickup to become locked.

I have a Technics CD player with a push button on the bottom to lock the laser into place. While moving the player I have accidentally pushed this button a few times.

William

Reply to
William R. Walsh

OK, I am assuming the replies to your other thread on the same subject didn't get you anywhere.

Have you checked the obvious? Things like the plastic CD mechanism being warped or damaged by the heat? Have you scoped the power supply rails to check whether the power supply electrolytics have been affected by the heat? Did you clean the laser?

By the sound of it, either the power supply is no longer providing a stable DC, or there are alignment issues caused by the heat. The latter may well prove impossible to repair without replacing the entire mechanism.

Incidentally, being able to 'see' the laser's output via a CCD camera or by naked eye is not indicative of a serviceable laser.

Dave

Reply to
Dave D

I fixed the CD player. As it turns out my suspicions were correct about the PSU. When A cd sarted up or the motor sled screw, and laser diode were powered up the LED would dim ever so slightly, this was really hard to notice becuase of the nature of LED's behaviour versus voltage. This indicated thre might be a PSU fault. I checked the voltage of all the voltage regulator IC's on the circuit board against the manufacturers IC parts minumim and maximum vallues. These were 5V dropper type voltage regulators, and there specified minimum output value was 4.83V. I registered 4.6V minimun when a cd was trying to be read, so there was obviously a problem here. I checked all the connections, they apperaed to be okay, no black marks or obvious component degredation. So I resoldered all the critical components in the PSU stages, i.e. transformer connections, diodes, power resistors and smoothing capacitors. I noticed when I powered the unit on that the LED was brighter and the operation of the transport and general cd loading was faster, and more importantly the unit actually played the cd!!

I expect the reason of fauilure was a simple mechanical fault, one of the solder joints in the PSU section was dry or cracked, possibly from excess vibration, being moved around the country so much.

This fix took me some time, to remove everything and these Rotel CD players are a bugger to work on, there are so many screws to get through. Anyway the AC supply probably wasn't being fully rectified so the supply current was halfed. In effect the voltage regulators were working but there was not enough current supply to keep the voltage stable hence it dipping, this efected the tracking to the extent that the cd player would mostly give up trying to read a cd.

Reply to
subseb

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