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On a whim, I purchased a complete type 5103 10-disc CD changer in unknown condition. At $160-delivered, I was certain I’d overpaid to take the “gamble”, but given my recent efforts to document the Datalink protocol, my curiosity got the better of me, as I wanted to see what efforts B&O went through to integrate this obscure, 3rd party rebranding of a Sony 10-disc CD changer designed to be placed in your car. (Short answer – a limited amount of effort, from what I can tell).
The unit arrived in VG condition, but frozen. I quickly discovered that work would need to be done in getting it operational – the tray elevator was non-responsive, resulting in nothing being loaded, much less mounted for playing. So I broke out my screwdriver and started to remove the outer shell in an effort to see how the thing worked.
It’s actually a quite clever exterior design, with the internal chassis mounted on shock bushings, designed to dampen the player while underway down a bumpy road. It’s designed to be mounted in one of two positions – either flat horizontal, with the cartridge coming out the side, or vertical, with the cartridge facing directly upwards (this would become a significant point later).
A few minutes of online research made me conclude that the Sony unit is most likely a Sony CDX-A20, a second-generation unit (the first-of-its-kind being an A10). On this note, it would appear that there is nothing different about the Sony part from a stock unit, with the exception of it being branded a “Bang & Olufsen” unit on the front. Given the identical mechanical nature to a stock A20, I’d venture to say that you could probably assemble your own CMM-10 on the cheap by purchasing a 5103 controller for $30, and finding a used CDX-A20 to plug into it. It’s also possible that an A10 would also work, as it uses the same 13-pin I/O plug.
After some gentle prodding of the main elevator gear, I managed to free the elevator from the grease-turned-glue that had bound it in place, and the unit began responding to ‘Tape Play’ commands. By ‘responding’, I mean it would pull out a CD and position it correctly, then fail to detect that the step had completed properly, and promptly return the CD to it’s holder. It would next raise the elevator to the next CD in sequence, and do exactly the same thing again, until it had gone through all ten slots, without playing a single CD. At least there was some progress.
After verifying the function of the light detection sensors, I began looking for some kind of mis-calibrated spring-loaded switch, or some other sensor that I had not yet seen. A bit more fiddling led me to the discovery that when I positioned the player in the upright position (remember from earlier that it can be mounted in 2 main positions), the sensors correctly detected the CD and promptly lowered it into position over the laser and began to play it – the unit was now working!
… ‘Ish’. Clearly I’m going to have to examine the capacitors and adjust the laser strength/focus, as some of the CDs were prone to skipping and/or getting stuck on sections of the CD. I’ll have to do some research on the laser adjustments for these Sony lasers, and find out of they are prone to the same issues that plagued the old Philips servo boards. My initial examination of the capacitors revealed a few familiar Sanyo units, which I tend to replace in the Beolink 7000 units.Great to see some documentation about these… they were often pictured hiding in the cube of a F1000 for obvoius reasons. 🙂
Location: Silicon Valley
My B&O Icons:
So, what can this unit do? For starters, it does work with a subset of basic Datalink controls. ‘Play’ plays, ‘Stop’ pauses, ‘< Step’ and ‘Step >’ work as they would with a standard Beogram CD player. ‘<<‘ and ‘>>’ have been commandeered to advance and return from one CD to the next, instead of used as ‘FF’ and ‘REW’ through a song (which may be commands that the A20 doesn’t support anyways). Although I have not tried it, ‘>>’ + number will skip to the CD in that position in the carousel. When one CD finishes, the next one is automatically loaded and played in sequence. On the plus side, the system is quite responsive, on par with or slightly more quick than the standard CD5500-7000. Unfortunately, on my unit, no current status information is transferred via Datalink, such as ‘Track number’, or even ‘transport status’, either via the Beolink 7000-specific protocols, a MCP 5500/6500, or a Penta status update. So in that sense, it’s a bit of a one-way system that responds to commands, but offers no listener feedback.
So herein lies my disappointment. the Sony CDX-A20 is designed to be used with a head panel on a vehicle dashboard, and has a dedicated pin for transmitting CD data to a display. But I get zero status on any B&O controller or Powerlink speaker- a wasted opportunity for a reasonable integration solution, which would have taken only a minimal effort to program.So there are a few places yet to explore for some definitive answers as to where any fault in the status reporting may lie. 1) Check the Sony data-out line for a signal denoting the sending of data. If present, then either 2) the B&O firmware is not responding as expected, or 3) hasn’t been programmed to pass on the Sony display status data via Datalink. My unit has firmware version 1.0 – I have seen a picture of a 5103 controller with firmware version 1.1, but without more knowledge, I cant speak to what changes are included in the later revisions of the controller.
Given the CMM-10’s limited integration, I can’t imagine that these sold all that well. For starters, the use of Datalink ’80 as a control protocol means that the CD changer has to reside reasonably close to the Beomaster, with it’s own exclusive 7-pin connection tied directly to the Beomaster in order to function, instead of in a cabinet somewhere, perhaps in another room – IMHO a clear limitation that lies in the chosen implementation. To me, any perceived market need by B&O was an opportunity to put a DL’86-enabled unit (or series of units – up to 7 total!) on the Aux MCL, and have it addressed via the Source “Unit” designation that the DL’86 protocol was designed for.Perhaps they were simply intended as a stop-gap solution for those customers who asked for multi-CD changers for background music, or commercial customers who simply wanted an un-managed 10-hour playlist. If anyone has more information on these strange-and-likely-rare-for-a-reason units to help me better understand the what/why/when/where of their genesis, feel free to add to the discussion.Here’s a cursory look at the 5103 internals.
It’s a fairly straightforward design, with a plastic light “Power” rod that I managed to snap the end off by not noticing it as I was disassembling the panel. Much of the logic is buried behind shielding, with a smattering of capacitors, including one huge 2200uF capacitor. For those individuals in 240V communities, the transformer does appear to be a dual-voltage transformer, part #8013435, which would make a voltage conversion simple. It also appears to share the same mounting points as several Beogram transformers I’ve been working on as of late, so a simple switch to an already-wired one would also be a possible solution. The transformer supplies +25V though a rectifier to two IC regulators, one producing 5v for internal logic, and the other producing 12V for the CD carousel.
Although there are shields on both sides of the board, the chipset is only on one side, with the shield on the other side covering the pin outs. Hiding inside the shield is a ROM chip encoded as 8341743 S/W1.0 and an MHS microcontroller – basically, the 1980’s version of an Arduino!
All-in-all, it looks like a straightforward solution from B&O to quickly address an apparent hole in the product lineup, and also reasonably well made. The capacitors all tested quite excellent, so if there’s an issue with corrupted status messages, it’s not a simple capacitor swap that will right the ship. If I had more time and patience (and interest, frankly), I’d look into updating the ROM with more capabilities. The easier solution will instead be to intercept status signals coming from the carousel, and interject proper status messages onto the Datalink bus, which the Beomaster will happily interpret as being valid. This would also be the spot to activate pin 6 with Datalink ’86, and code for DL ’86 interoperability. All doable, but admittedly well down in my list of priorities.
I’ve spent the last few days pulling my hair out trying to figure out all of the mechanical switches and levers on this thing. After several “one step forward, two steps back” moments (I had to disassemble the carousel twice because the elevator kept trying to shove CDs into already occupied spots) I finally got to the point where it could reliably once again cycle through a tray of CDs – loading and unloading, but failing to play anything – even failing to play with my prior hack of “upright position”. So with nothing playing, I was consigned to spending a few hours looking at ribbon cables, cleaning any mechanical switch I could find, and scouring the Sony service manual for clues as to why it wont accept a CD as “Loaded”. I finally zeroed in on this board, which handles the elevator mechanism.
Perhaps a bad seating or broken trace was the issue. Among other things, the board has 2 photo sensors – one to determine if a CD is in the player, and one to determine whether the CD is fully seated in the player tray.
I concluded that one or the other of these sensors was likely intermittent, causing the controller to determine that there was a CD jammed in the system. The readings for the “CD inserted” was indeed reading a medium short. And yet, it appeared to always be working for a specific dark-gold-colored CD, no matter where it was placed in the carousel. Odd!
… and then it hit me. These photosensors are designed to operate in total blackness. And here I was – for days – trying to poke and prod and shine my 3000 lumen desk light inside the internals to try and discern why the darn thing was not working, all the while causing the “CD Inserted” photoreceptor to constantly report a CD jam.
Ugh – I’m an idiot! I switched off my desk light, and everything began to function properly. For now – I have a hunch there are still a few gremlins left to be discovered. And they don’t like bright lights either.
I’ve got a Sony CDX-A55 inbound that I bought for $30 off eBay which has the same pinout at the A20 – a slightly newer configuration to the original setup. I’d like to definitively know how easy it would be to add a 10-disc CD changer to an 80’s – 90’s Beosystem. Controllers tend to run $60 or so on eBay, so for under $120, you can add a 10-disc changer to your pizza box system for parties.
Clearly it would not have the panache of a 9000, but it would retain most of the function. On that note, I can report that the system works just fine on a Beomaster 5500 Tape or Tape 2 input with fully functional control via a Beo4 or MCP 5500, as I had expected. I have not attempted it yet, but I’d expect it to work with a 5000/MCP5000 as well, as the Datalink ’80 commands required to make it respond should be identical.
The Sony packaging is basically a metal endo-skeleton surrounded by a molded-plastic shell, with large rubber suspension bushings to deal with rough roads – something unnecessary when installed in the home. Unfortunate that B&O didn’t really bother to repackage everything in something a bit more B&O-ish. There’s absolutely no reason why the system & controller together could not fit in a form factor similar to the pizza boxes (it would admittedly need to be slightly taller) with a metal sliding door to cover the carousel – even the eject button in the usual left corner location would be compatible, and require nothing more than a wire extension to function.
Add a switch to choose between Aux and Tape 2 communication – a trivial addition for a competent programmer, and the system would have been quite versatile. Shoulda coulda woulda.
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