cold water

Reviving a Sony CDP-991, Part 3

In the last part, I made the tray operational. It's a precondition for this part: Inserting a CD.

Third Problem: Stuck Sled

In the opened tray, I put a random CD from my shelf. Then I pressed the close button. The tray closed, and a few seconds later, the player showed the number of tracks and total playback time. Yaaay! ­čÄë The optical pickup seems to be working.

Daringly I pressed the play button, the disc started spinning, and then...

Nothing. No playback. Just silence.

I also noticed that the characteristical noise of the moving sled was missing when I changed through the tracks.

My first thought was that the laser was worn out after all. But then, on the other hand, the pickup would not have been able to read the CD's table of contents. It rather seems that the sled was stuck.

The optical deck with the pickup on the sled I disassembled the drive again. The pickup moves on a metal shaft and a plastic strip. Both were greased. I carefully removed the old lubrication with cotton buds and isopropanol, then applied a tiny bit of fresh silicone grease.

Next attempt... And this time, it was successful! After about 15 years, I heard music from my good old CD player again!

But I'm not done yet, as I already spotted some more problems. The player refuses to play higher track numbers, and the sled is still making strange noises on a track change. Also, the volume potentiometer crackles awfully and needs some cleaning. More of that in the next parts.

Reviving a Sony CDP-991, Part 2

In the first part, I powered up my CDP-991 again after 15 years. Next step: Open the tray.

Second Problem: Weak Tray Belt

The replaced tray belt I pressed the "open/close" button, and the tray opened. I pressed the button again, and the tray closed. Almost. After a few seconds it opened again. Obviously, the mechanism got too weak to completely close the tray.

The exploded view in the service manual revealed that the tray is moved by three gears and a belt. I removed the drive and then the tray, to expose the tray belt. Indeed, it got flabby over the years.

Warning: There are live parts inside the case. Before opening it, always unplug the power. If you are going to plug in the power while the case is open, always take appropriate measures to protect yourself from accidentally touching live parts. If in doubt, better ask a trained person for help.

It was easy to find a new tray belt on the Bay for just a few euros. I ordered one, and it was already delivered the next day.

After replacing the belt and assembling the drive, the tray finally opens and closes now. It is a clever construction. The top gear moves the tray. When it is almost closed, the gears are pushed sideways and turn the cam below (the silver part in the photo). The cam pushes up the optical deck and clamps the CD to the spindle. This part of the movement takes quite a lot of force. Too much for the old and worn-out belt.

It is a good idea to replace the belt on spec, after all those years. If the tray still won't close, the culprit might be the switches on the tray motor assembly. On the photo, you can see their "tongues" to the left and right of the motor. These switches detect when the tray is fully opened or closed. The contacts may have become dirty over the years, and just need some cleaning. Since my player's tray is operating normally now, I postponed this "fun" to a long and boring winter's day. ­čśë

The next step is critical. Is the laser pick-up still operational after all those years? Let's find out! I'm going to insert a CD.

Reviving a Sony CDP-991

Let's do a hardware related project for a change. A few days ago, I found my good old CD player from the time when I was in my early twenties. It's a CDP-991. Sony has produced them around 1991.

I still remember when I was in a HiFi store and gave the CDP-991 a try. I brought my "horror CD" with me. It had a few deep scratches from a careless handling of mine. My old CD player at home could play track 1 with a lot of skipping, and capitulated on the next tracks. I wondered how the CDP-991 would play it. Maybe it would play track 1 with almost no skips, and even a bit of the next tracks? I was flabbergasted when the player was totally unimpressed of the scratches, and just flawlessly played all the tracks. I bought the CDP-991 on the spot. ­čśü

It was the component of my HiFi equipment that I was most proud of. And even many years later - in the times of mp3 players, smartphones, and streaming - I never had the guts to throw it away. It sat in a cardboard box, buried in a storage room, patiently waiting for me to rediscover it. Now is the time...

Today I have turned on my good old CD player for the first time after maybe 15 years, and it just started up. I was happy to see the display light up again.

However, 27 years surely left its marks on the device. Let's find out how bad the damage is.

First Problem: Amnesia

Feed me! The CDP-991 is equipped with a feature Sony calls "custom file". The player is able to recognize up to 185 discs. One could set the CD title, delete boring tracks, and store individual index marks. One could even customize the "NO DISC" text. I have changed it to "-FEED ME-" back in the old days, as a reference to Audrey II from the musical Little Shop of Horrors.

This custom text was gone now, and the player greeted me with the standard "NO DISC" again.

I wasn't too much surprised of that. Today we are used to store large amounts of data on SD cards, which retain them for tens of years without power. At the time the player was built, EEPROMs were the only non-volatile memories on the market. They could barely store a few bytes, far from 185 disc titles. For those amounts of data, it was more common to use static RAM and a backup battery.

I expected that the battery was empty and due for a replacement. Even worse, leaking battery acid could have damaged the PCB. I opened the case and looked for a backup battery, but found none. So I hoped to obtain a circuit diagram and find out more about how the player stores its data. After just a few minutes, I found the official service manual as downloadable PDF in an excellent quality. The internet is awesome!

The manual had good news for me. Instead of a battery, Sony has used a 0.1F capacitor, which is able to retain data in the static RAM for about a month without AC power. It ran out of energy long ago, but all I had to do was to reconnect the player to the mains to charge it again.

Of course, the first thing I did was changing the "NO DISC" text back to "-FEED ME-".

The first problem is fixed. Next step: Open the tray.

Sombrero de Chasna

The "Sombrero de Chasna" is a table mount that is 2400 meters tall and looks like the top of a sombrero hat, hence its name.

Our hike starts at the ├írea recreativa Las Lajas. It's a public picnic site with a parking area that is sufficiently big, but the poor road conditions of the last few meters make it difficult to reach unless you have rented an SUV. ­čśů

From there we start the ascent to the summit of the Sombrero. The trail is a little hard to find. At some parts, only cairns show the way. A few minutes away from the Sombrero, there is the caldera edge with a spectacular view on the Las Ca├▒adas plain.

The hike to the summit is a little exhausting. You certainly need good hiking shoes, hiking poles, and a good condition. But the spectacular views are worth it. It's the third time we have been up there now, and definitely not the last time.

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Fedora 28 auf einem Ryzen 5

Es wurde Zeit f├╝r einen neuen Linux-PC. Und da Intel in letzter Zeit mit Meltdown und mit Sicherheitsl├╝cken in der Management Engine keine allzu gute Figur macht, dachte ich mir, es ist wieder an der Zeit, AMD eine Chance zu geben.

Was ich haben m├Âchte, ist ein Arbeitsrechner mit guter Rechenleistung und schnellem Massenspeicher. Die Grafikleistung ist sekund├Ąr, da ich nicht spiele. Wichtiger ist mir ein ruhiger Betrieb, was die Reduzierung von Abw├Ąrme durch einen Strom sparenden Prozessor beinhaltet.

F├╝r meinen neuen Rechenknecht im Retro-Look entkernte ich ein Towergeh├Ąuse von 2004, das ich noch hier stehen hatte und einen AMD Athlon 64 mit ├╝ppigen 4 GB DDR2-RAM beherbergte. Nach der Renovierung besteht der Rechner jetzt aus:

  • CPU: AMD Ryzen 5 2400G. Die eingebaute Vega 11-Grafikeinheit bringt bei Benchmark-Tests eine respektable Leistung und reicht f├╝r meine Zwecke locker aus. Zudem begn├╝gt sich der Ryzen 5 mit 65 W TDP. Eine f├╝r diesen Einsatz eigentlich ├╝berdimensionierte AIO-Wasserk├╝hlung sorgt daf├╝r, dass die CPU-Cores auch l├Ąngere Zeit im 3,9 GHz Turbo-Modus durchhalten, und l├Ąsst mir die Option f├╝r sp├Ątere Overclocking-Experimente.
  • Mainboard: Asus Prime X470 Pro. F├╝r diese Wahl gab es keinen besonderen Grund, au├čer dass ich in der Vergangenheit mit Asus-Boards gute Erfahrung gemacht habe. F├╝r die Linux-Kompatibilit├Ąt ist die Nennung des verwendeten Typs aber vielleicht interessant.
  • SSD: Samsung 970 Pro, 512 GB, PCIe M.2. Massenspeicher sind die Komponenten, die im Rechnerleben erfahrungsgem├Ą├č als erstes ein Upgrade erfahren, weil sie zu klein oder zu langsam geworden sind. Also lieber gleich schon beim Neukauf klotzen statt kleckern. Das z├Âgert das Upgrade ein wenig hinaus.
  • RAM: 16 GB DDR4-3000, als Kit mit 2x 8 GB. F├╝r meine Zwecke reicht das. Der Ryzen 5 unterst├╝tzt maximal DDR4-2933, so dass h├Âher getaktete RAMs wenig Sinn machen. Da sollte man lieber mehr Geld f├╝r eine m├Âglichst geringe CAS Latency ausgeben.

F├╝r Linux gibt es hier gleich mehrere Herausforderungen. Die Vega-Grafikeinheit ist verh├Ąltnism├Ą├čig neu, dementsprechend neu ist auch der Support im Linux-Kernel. Zudem ist die SSD nicht per SATA, sondern per PCIe angebunden, was ebenfalls - zumindest theoretisch - zu Treiberproblemen f├╝hren kann.

Der Versuch, eine Fedora 28-Live CD im Cinnamon-Spin zu starten, funktionierte auch prompt nicht. Das System startet bis zur Anmeldemaske, aber man kommt einfach nicht dar├╝ber hinaus. Erst ein Start im minimalen VESA-Modus erlaubte es, eine reduzierte Cinnamon-Oberfl├Ąche zu erreichen und den Installer auszuf├╝hren.

Zumindest meine Sorge, die PCIe-SSD w├╝rde nicht erkannt werden, erwies sich danach als unbegr├╝ndet. Der Installer erkannte die SSD und richtete problemlos und z├╝gig das Fedora-System darauf ein.

Beim ersten Reboot startete Cinnamon aber weiterhin nur im reduzierten Modus ohne Compositing. Abhilfe brachte, den nomodeset Kernel-Parameter aus den Grub-Einstellungen zu entfernen. Nach einem weiteren Reboot stand dann die volle Grafikleistung zur Verf├╝gung. Vermutlich hat das Live-Image einen zu alten Kernel, so dass das kommende Fedora 29 problemlos installierbar sein wird.

Von den anf├Ąnglichen Problemen mit der Grafik abgesehen, l├Ąuft das System rund. Netzwerk, Sound, SATA- und USB-Schnittstellen wurden von Linux erkannt und werden voll unterst├╝tzt. Selbst unter Last verh├Ąlt es sich stabil, bisher hatte ich keine Freezes oder unerwarteten Abst├╝rze.

Mein Ziel habe ich damit erreicht. Der neue PC bringt eine ordentliche Leistung und ist trotzdem leise, k├╝hl und sparsam.

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Sunday, August 12, 2018