Friday, September 23, 2016

Fixing SONY CDP-XA50ES "File Clr" Amnesia

Fixing SONY CDP-XA50ES Amnesia

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!

Tuesday, September 6, 2016

Logitech / SlimDevices Squeezebox Classic Display Replacement Guide

Squeezebox Classic (v3) Display Replacement Guide

Hi folks! With the Squeezebox Classic 3, a rather rare item was here today for a display refreshment. I'd like to share the experience with you of course.
Please take a look here for general information on VFDs and what is their problem.
If your Squeezebox Classic display has faded or has shadows, you've come to the right place.
An example of what I mean:


Or even worse:




You'll see the new display in comparison later.
 

Tools Needed

What you need for this repair is:

  • a T10 torx screwdriver
  • a spudger or flat but stable piece of plastic to remove adhesive pads
  • Noritake MN32032-type VFD glass module (MN32032A is current)
  • desoldering station (~ 320 °C, no more than 60W) and leaded solder
  • soldering iron with fine tip (~ 285°C, no more than 40W)
  • isopropylic alcohol (95% pure or better) to clean things up
  • recommended: 3M 08984 adhesive remover  
 

Tools Not Recommended

The solder pads on the main board should get as little stress as possible. So they should not be heated too much or they will easily come off the board, adding a completely new level of difficulty. So please use temperature-regulated soldering equipment, the reliable / expensive sort if possible.
I do not recommend using solder wick to desolder the old display. It takes too long and will not completely remove the solder in order to loosen the display.
When it comes to cleaning, avoid paint thinner or any other stuff that harms plastic surfaces. It is probably no good for the mainboard, too.
 

Disassembly: Open the Case

Remove the two screws indicated here:
 

You can remove the front piece of the housing now, if it didn't fall off already. Beside these screws nothing holds them to the back casing but you may need to pry the gap between both halves a little.
What you are going to see: the display in its full glory, the IR receiver diode, and a row of connection pins.


Please take a second to check the inside of the front cover. It is typical that it collects a very fine dust on the inside due to static charge. If you move your finger, or a cloth, over the surface, and it is then grey or even black, some dust has accumulated. It causes the display to appear milky so it should be removed for the desired like-new experience.
What you may also see is that people before you have tried to remove the dust. I would say that was not a perfect improvement though. The dust is gone but the surface is full of thin scratch marks:


Again, this photo is from is the inside of the display cover. It may look similar on the outside though.
Be aware that we are dealing with plastic here, no glass, and the surfaces are absolutely delicate so if you go off and clean it, use the softest materials available. We will come back to this later.
 

Disassembly: Loosen the Mainboard

Undo these four TX10 screws indicated: After that, a slight push on the connectors at the back of the device is all you need to get the board out of the case completely.


A quick view of the back side of the mainboard: 


Now, similar to what you can find in the Boom repair blog, you will have to follow these steps:
  • desolder the display (18 pins, 2mm spacing)
  • cut the adhesive pads beneath the display
 

Desoldering the Display

To desolder the display pins, my recommendation is you use a quality vacuum desoldering station. Alternatively, you may try one of the manual one-shot vacuum pumps but it's considerably more work. As the old display isn't worth anything, you can also cut all its connections with a side cutter, then get rid of the display, and eventually desolder each pin one by one. You will still need to free up all the 18 holes one way or the other to put the new display in.
While in the Boom repair guide I tried to explain how to desolder with a vacuum station in pure text, I have created a video here that shows the desoldering process on the Classic: https://www.youtube.com/watch?v=XDod-obw6Iw

Once the display pins are free, we can go ahead and remove it entirely.
First off, the display is stuck to the mainboard with two adhesive pads, one on each side. Luckily there is just the flat PCB surface directly under the display so there is little risk of damaging components. Still, there is no need to be careless. Some traces hide under the display and they should not be scratched.
Use a spudger with a sharp edge to cut through the adhesive pads on both sides.

 
Viewed from the side; observe how the spudger is slightly bent and the cutting edge stays close to the glass, not the board (to avoid accidental damage to PCB traces):


See here the remains of the adhesive pads once the display is out:


I can totally recommend the following to remove the pads. Isopropylic alcohol will do it but more slowly. The 3M chemical is a powerful agent that softens up almost any sort of adhesive:


You'll probably have a lot of trouble removing the pads without a solvent. While it is not vital to clean it up perfectly, why not take the time?
Using the 3M stuff is easy. Just soak up the remains of the adhesive pads and give it some minutes to do its magic. Soak it up another time and let it sit for a minute. After that, the pads can virtually be pushed off from their position even though I would advise you to pull them off to avoid smearing the adhesive remains.
And there will be some remains once each pad is gone. The adhesive layer is still there but now you can wipe it up with a cloth. If need be in multiple steps, and with another application of 3M. Eventually clean everything up with Isopropyl Alcohol.
The result rewards you with a board good as new:


 

Putting the New Display

The adhesive pads mainly serve the purpose of keeping a little distance between the display and the board (about 2mm, I would guess), and ensuring that the display cannot move. You could set the new display flat on the mainboard with no distance at all, and use double-sided adhesive tape to secure it, however, that spacing might make sense, so this is a nicer alternative:


This is basically double-sided tape with a foam layer in between. It is available in all shapes and sizes and thicknesses. Try to find one that has about the same thickness as the original pads. Craft shops are usually full of them, otherwise eBay or Amazon might be your source of choice.
Before you put the adhesive pads down, please exercise placing the new display. Its 18 pins need to go straight into the holes, none of them should be stuck anywhere. If that works out, stick it down with as many adhesive pads as you desire.
Now we can start soldering the pins. After you soldered the first three pins on one side of the display, take a look at it from the side to ensure that the distance between board and display will be the same on both sides. Therefore, it is best to solder down the other three pins on the far end before turning to the twelve pins in between.
Logitech's production process is mostly automated but the display was hand-mounted. You can see that from solder flux residue around the pins of the old display. As it is likely that your solder wire has flux built-in, more flux will accumulate. Besides looking ugly, it may also be pretty aggressive to the board so my recommendation here is to remove it all after you are done soldering. Isopropyl is ideal here again, best combined with a toothbrush.
With little effort, you can make it look like this:


Please inspect your work carefully. The outer sets of three pins may be shorted. That's not a problem because they have the same potential anyway. Check the other pins, too.
If you have a multimeter or other means of continuity checking device, use that to ensure that each pin is a different potential than its neighboring pin(s).
 
Here is what these pins are, it may help you determine pins that may or may not be connected to each other, and the expected operating voltages:
Pin/group Specification Typical voltage range Description
1..3F1+5V DCFilament Voltage 1 (block of three pins on the extreme left)
4..5NC
Pins left out (not present) to separate filament voltages from other signals
6VDD2+55V (!)High-voltage rail for grid. Be sure not to touch this pin or accidentally short it to any other pin
7..8VSS (GND)0VDigital ground (these two pins are internally joined together)
9VDD1+3.3VDigital supply voltage for internal circuitry
10BLKunknownDisplay blanking input
11LATunknownData latch control
12GCPunknownTone control pulse
13SOUT2unknownSerial data output 2
14SOUT1unknownSerial data output 1
15CLKunknownShift register clock
16SIN1unknownSerial data input 1
17SIN2unknownSerial data input 2
18..79NC
Pins left out (not present)
80..82F21.4V to 3.9VFilament Voltage 2 (must be lower than F1, in the block of three pins on the extreme right)
Once that is done...
Testing time!
For the first test, I left the board outside of the case so I could quickly intercept if anything goes bad. Greeted with a logo so bright it is almost blinding:


Nice! Putting it all back together is basically doing the disassembly in reverse. 
But while it's still open, you may consider to review the SMD capacitors. If the SB3 appears to become unstable, for instance reboots when playback starts, or reboots multiple times before it can be used on powerup, you may want to check the SMD replacement guide here: https://joes-tech-blog.blogspot.com/2018/11/logitech-slimdevices-squeezebox-classic.html

Don't forget that the four shorter TX10 screws are the ones fixing the mainboard inside whereas the two longer ones are applied from the back of the device to hold the front piece of the case.
Finally:


Taking a look at the poor little old display, I noticed a considerable amount of burn-in! See how you can easily read (German) text here?


So that display had the worst form of aging. The pixels covered by the text have burnt so bad they actually went darker than the surrounding ones.
It probably sat around uninterrupted for years, just showing the first step in the setup process. So that Classic wasn't even used most of the time. Why the owner had it plugged in at all remains a mystery.
 

Advice for VFD Display Maintenance

If you like to get more information about VFDs and how they are best treated in operation, you may want to read this article. It discusses failure scenarios and also some advice how to avoid damage in the future.

Final Words

I hope you liked this guide.
If you want to have this repair done for your Squeezebox, feel free to contact me. I am available as JoeMuc2009 in the US-based SlimDevices Forum, or  as JoeMod2015 in the German Squeezebox Forum. Or just drop me a note here in the comments. Or contact me via e-mail to johannesfranke74@gmail.com.
I have collected experience with Squeezebox devices for some years now and can fix more issues than just the displays. Always glad to help so don't hesitate :o)

Cheers,
Joe
 

Legal Concerns

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!