Friday, September 23, 2016

Fixing SONY CDP-XA50ES "File Clr" Amnesia

Fixing SONY CDP-XA50ES Amnesia

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Here's another repair documentation. For some months now, my beloved XA50ES would greet me with this message whenever I switched it on:

 

This symptom may appear in a lot of Sony CD players. It is likely that the instructions given here can also apply partially for other models. The basic principle is very similar at least.

A lot of Sony CD players support the "CUSTOM FILE" function which means that the player can store your favourite program for up to 224 separate CDs (in the XA50ES at least, the actual capacity may depend on the model). A CD is recognized by its unique TOC layout, and if a custom file for the CD was created before, that very same program will run once the disc is inserted at a later time.
The custom file information is stored inside the player. If the "FILE CLR" message appears at powerup, this means that the custom file memory was lost which is no concern for most people but a nuisance for many others. And it means that there is a defect in the player that should be dealt with.
Surprisingly, looking up this problem in Google does not reveal any useful result. So it might not be a very popular issue. Anyway, hope that this helps somebody :o)

Back when the XA50ES was designed, flash memory was not available yet so the information is stored in a 64 kByte CMOS SRAM. The exact model is Sanyo LC3564SM-10, advertised with extra low standby consumption around 1µA. Typically, SRAM loses its contents as soon as power is gone. To avoid that, Sony designers chose to supply some standby power from a capacitor that gets charged when the device is on, and holds its charge for some time after the device is switched off.
Older devices would have a battery holder somewhere on the back of the device to provide standby power for the RAM. This caused lots of trouble as usual AA or AAA cells would start leaking sooner or later, anyway much sooner than any internal capacitor.
But capacitors are always the main suspect when a device goes bad after 20 years or so. In this case, we have a high-capacity one (a.k.a. gold cap). It has a capacity of 0.1F which is quite a lot in comparison, especially with respect to its minimum form factor.
In the schematics, it can be found - as expected - in close proximity of the RAM chip IC202. The capacitor marking is C201:

C201, our culprit, in the red circle.
So the symptoms clearly indicate that the RAM is not supplied enough power when the player is off. Measuring the voltage results in around 5.5V in powered state, and that rapidly drops to 0V when power is off which proves that the cap is dead.
The XA50ES is pretty service-friendly. We just have to undo six PH2 screws to remove the top cover (which alone outweighs some more modern players!)


All control logic is on the servo board which hangs upside down above the drive. To get to the PCB, loosen another four PH2 screws as indicated here (the screws were already removed when the photo was taken):



Unplug three connectors at the left and four connectors at the right side. You can then flip the entire frame to the back which exposes another three connectors:

 

The black multi-wire power connector at CN91 (near the lower left corner of the PCB) unplugs easily. Please be very careful with the delicate white flat flex cables though (CN101 and CN102). The cables should not be bent sideways or you will risk tearing them. They have a narrow tolerance margin, and spares are practically impossible to obtain, so treat them with respect. To loosen the connectors, gently pull the connector's white tabs towards you which stick out to the left and right side. Try to do this simultaneously on both sides to avoid putting anything askew. The tabs and the lower part of the connector should slide out for a millimeter or two which unlocks the flat flex so you can pull it out of the connector.


We get a first look at the gold cap here, it's this one:


What you can also see is the light barrier that is used to check whether the CD puck is in position or not. The two black plastic pieces near the center of the PCB host an IR emitter and detector. The barrier needs to be interrupted in order for the player to do anything.
Now for the cap, up closer and from the other side:


After removing all cables, unscrew six PH2 screws here to separate the PCB from the metal frame:


Now the solder side of the PCB is exposed, and we can remove C201 safely.
I was a little disappointed to find this side of the PCB looks pretty crusty, unlike the side with the optical components which is totally clean. Functionally that's no problem but they could have considered cleaning up the entire PCB.


Be sure to remember the polarity of the original capacitor. While it appears standard that the top contact that wraps around the side of the capacitor is the negative terminal, your replacement might be different in some way. Caps don't like reverse polarity so better be sure to get it right in the first attempt.


While C201 looked fine on the top side, we need to thank gravity that the cap is usually hanging upside down. That way, the corrosive stuff it spilled didn't reach the board. Actually the PCB looks like it has not had any contact with it. Lucky!

So yeah, that's ugly
To find a good replacement, let's take some measurements:

We could afford up to 15mm in height (higher components would collide with the rotating CD). The old cap took about 4.5mm in height.

The pin-to-pin distance is 11mm



The diameter is approx. 11.5mm
I found the Panasonic EECS0HD224H is a good replacement here. It has the same maximum voltage (5.5V), takes 6mm in height, has the same pin distance as the old one and a smaller diameter. And even better, it has more than twice the capacity (0.22F instead of 0.1F) so chances of losing file data is reduced, too. Plus it's quite affordable at 1.19€.

Panasonic GoldCap vs.the leaky Elna 0.1F cap (above)
 It's a little out of center regarding the silk screen due to slightly different dimensioning but who cares.


And that cured it! The "FILE CLR" message appeared again after the repair of course, not much of a surprise though. After giving the cap a minute to get charged, another power cycle reveals that the custom file function is back working and "FILE CLR" no longer appears! Cool.

Reassembly steps:
  • join the PCB and the metal frame back together. There is only one way everything fits. If it does not appear to fit in the first attempt, compare the pieces to the photos above. Eventually secure the PCB with six PH2 screws
  • position the unit in the same arrangement as when you dismounted it (flipped upside down)
  • plug the power connector (CN91) first and route the wires through the cable holders at the back of the PCB so they are out of the way for the next step
  • slide the white flat flex cables back into the connectors. For each of the cables, do this:
    • Ensure that the lower part with the tabs on its sides (which you pulled out to loosen the cables) is still in the "pulled" position, otherwise it is hard or even impossible to insert the cable
    • Be sure to keep it horizontally level and hit the slot properly so you don't accidentally push the cable under the connector
    • The cable should slide in with little force until the metal conductive stripes are almost completely inside the connector
    • At some point you will notice the cable is at its end stop when the cable's metal contacts are exposed by no more than ~0.5mm. The cable cannot be pushed in so far that the metal contacts are no longer visible so that exposure is okay
    • Ensure the cable is not at an angle, then push the white tabs back towards the connector until they lock in their end position
    • I found it helpful to tack the cable to the board in its end position with an adhesive strip across it so it does not slip out when you have no hand free to hold it. That way, you can direct all your attention to closing the connector
    • Eventually, gently pull the cable to ensure it is fixed properly. It should stay where it is of course.
  • put the metal frame into its original position and secure it with the four PH2 screws
  • plug in three connectors (blue, white, red) at the left side. Remember the cable that ends in the white small connector comes from the right side of the unit, and should be routed around the back of the frame, using the same cable ties that also secure the power wires
  • plug in four connectors (small white, white, red, white) on the right side. If you cannot find the small white connector, it might be buried somewhere. It is connecting the optical digital output to the servo PCB so if you start tracing it at the TOSLINK port, you will easily find where it ends
Hope you enjoyed this, and good look for your own repairs!
Cheers,
Joe

Final Words

Some legal stuff because you never know: please bear in mind that I am writing this as a hobbyist, not a professional. I describe personal ideas here which is only one of many ways such a repair can be achieved. I cannot guarantee that following this guide will lead to a good result, and cannot be held liable for any personal, physical, or monetary damage anybody suffers by following this guide.
I am open to advice if anything described here is wrong or can be done better. Please let me know in the comments if you find there is anything left to be desired.
Thank you!

2 comments:

  1. Hello Johan, how can I contact you in regards to another XA50 problem?

    ReplyDelete
    Replies
    1. sure, if you like, please write to "johannes_franke at hotmail.com" (you know, please make a valid email address out of it first). Hope I can help.

      Delete

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