Meridian 506.24 CD Player Service & Mystery Fault Repair

The Meridian 506.24 is a seriously good CD player, one of the very best I’ve had the pleasure of listening to. This 506, however, had a strange, mystery fault. Read on to discover how I serviced and finally fixed this stunning CD player.

If you want a smooth, relaxed, organic-sounding player, you’ll go a long way to find one better than a Meridian 506.24. Meridian really were on a roll when they produced the 506, 507 and 508 series of CD players, from the mid-nineties. All are superb players, easily beating most players even now, despite what you might think.

In fact, I like the 506 so much that this unit has become my reference CD player. The only thing I need is a matching Meridian remote – anyone maybe have an unused remote lying around…?

I like the look of this series even from the front. The combination of blacks, matt plastics, metal and glass works very well and the 506.24 is a very well-made player.

Plenty has been written about just how good the 506 series sounds, especially the 506.24. This TNT review is a good starting point. If you want a few more technical details, revision history and owner’s manuals, check out the very useful Meridian-Audio Info page about the 506.

I’ll review the 506 in an upcoming piece. In this article, I’ll outline the original service and repair work I did to the player, laser replacement, the unit’s mystery fault, and finally, the moment I uncovered the underlying fault that lay dormant in this 506.24 for many years!

Standard Service – The Mystery Begins…

This 506.24 came to me for service last year, exhibiting a fairly common fault with the loading mechanism. I repaired the fault with the loader and serviced the player, all fairly standard stuff, requiring no major surgery.

With the lid off, let’s take a quick look at the Meridian 506. I think this is pretty self-explanatory, but note the nice touches like custom-designed and built metal loader and tucked away at the rear of the player, the discrete class-A output buffer. Very nice to see this and just part of why the 506.24 sounds so good.
Here you can see the VAM 1205, set into the completely custom Meridian plastic and metal loader. Note that this is the original laser.
Here’s a closer look at the class-A, discrete output buffer. Astute observers will pick out the tantalum capacitors, Nichicon MUSE caps and WIMAs, all expensive parts. Note the tray load motor in the background.
I took all of this apart for cleaning and lubrication, standard in a service like this. This area needs a little time spent on it to get things running smoothly.
The loader drive gear and drive belt always need attention. In this case cleaning, lubrication and replacement of the drive belt.
These Teflon strips sometimes become detached and caught in the mechanism on the 500 series players. I re-glued this strip and made sure everything else worked smoothly before reassembly.

So, with the loader serviced, everything cleaned and lubed and back together, I plugged the player in, hoping for a smooth running drawer.  The drawer did indeed now work perfectly, but the player would not read a disc. WTF..?

Extended Repair – New Laser/Mech

My testing of this 506.24 showed that the spindle motor wasn’t working properly. It seemed to be getting power, but not spinning. All CD players eventually need replacement lasers. Laser power output drops over time. Eventually, power output will drop to a point where the energy reflected off the disc is no longer enough to enable correct focus and tracking. Sometimes spindle motors also fail and, based on the symptoms, that seemed to be the case here.

The 506 was manufactured with two different Philips laser mechs. This unit uses a VAM 1205, but others seem to use a CDM 12.4. I have a supplier of both CDM 12.4 and VAM 1205 mechs. Much has been written about these mechs and there is much much misunderstanding about them. They are NOT interchangeable. The VAM 1205 has a hall-effect motor, whilst the CDM 12.4 uses a standard DC motor. You have to use the right part for the player in question.

Anyway, I chatted with the customer and explained the situation. Obviously, this deeper fault had to be repaired and this would take a new mech and possibly a bit more troubleshooting. I felt that this was worth doing, but the owner just didn’t want to proceed any further. Instead, he very kindly offered to donate the unit to me, as project or for parts. Thanks again Jed, your donation is genuinely appreciated.

Some months later, I replaced the laser/mech, not sure if this would fix the problem.

So to take this repair to the next level, the entire loader/mech has to be removed. There are lots of little screws and washers, so organisation is important when working on anything like this.
With the loader/mech removed, the laser and motor drive circuitry is revealed. I carefully examined all of this for faults, measured capacitors etc.
This is the loader/mech still attached to the main tray assembly. Note the ribbon cable of the VAM 1205 motor. This is different to the two-wire loom of the CDM 12.4 motor.
This is the laser mech carrier, removed from the main tray. Next, I carefully removed the old mech and installed the new one.
This is the new VAM 1205 assembly. I should mention that these are not genuine Philips parts, which are NLA. They are in fact clones, possibly remanufactured from original Philips parts, with some new bits added. Either way, the units I get work well.
The Ah-Ha moment!

So, with the 506.24 serviced, months having passed and now with a new mech installed, you can imagine my anticipation about finally testing her. I carefully put everything back together, not a trivial exercise, inserted a test disc and hit play… Nothing. The player was still dead. Not happy.

This 506 obviously contained a fundamental flaw that was preventing her from running. Further testing now showed that the spindle motor was getting intermittent power, but why? I spent several hours going over the drive and control board.

Finally, after much time spent tracing power and other circuits, I found it. It’s evident in the image below, I wonder if you can see it?

This is the power supply for the laser and mech. I traced motor power from the connector at the right, onto the board. From there, power runs up to the soldered-in fuse, top-right. This is a nice touch by Meridian engineers, designed to prevent over-current damage. When I probed the fuse however, there was a spark from the joint…
Resolution – Final Fix of the 506

So, I found my smoking gun. A very dry joint in the mech power supply causing an intermittent break in power to the motor. This fault had obviously been there a very long time. The joint would have been barely adequate when manufactured, and then gradually deteriorated over time to the point where simply moving the player would have caused it to fail.

In other words, simply delivering the player to me, was probably all that it took to finally break the joint completely. Once broken, the player could never read a disc again, until I repaired this tiny, hard to find fault. I wonder how many Meridian 506s were scrapped because of a fault like this?

Finally, I’d found and fixed the fault that accounted for the intermittent symptoms and other weird effects I’d observed. I reflowed the joint and the player sprang back to life, working perfectly from then on.

Apologies for the grainy enlargement. Look closely at the joint I’ve highlighted. You’ll see there is no solder on it, likely none on the bottom pad either. This lead was free to wiggle, wiggle, wiggle, wiggle, wiggle – yeah. When my DMM probe bridged the gap, current flowed, causing the spark. I’d found the problem, by tracing the circuit. The fault was there for a long time, I suggest the joint was only ever marginal and, as time passed, it became a point of failure.
Finally, this beautiful Meridian 506.24 lives again! Partnered up with my modified Tri-Vista 21, this is a killer player/DAC.

This wonderful Meridian 506.24 CD player plays on as part of my system, for now.

I’d be very happy to service or repair your Meridian 506, 507 or 508. Get in touch to start the conversation!

17 thoughts on “Meridian 506.24 CD Player Service & Mystery Fault Repair”

  1. Thanks for your reply, Mike! I lack diagnostic equipment (other than DMM) so inspect and replace is the only method available. I’ll go over the board again – this time with some magnification, like you advise. Did you remove the power board to inspect the underside (because it looks like a whole lot of aggro to get that out)? I’ve ordered a replacement vam1205 from China anyways, as I’ll be trying to extend life of this 506 regardless. While I have your attention, if I get the laser functioning again, should I go to the effort of replacing all electrolytics (inc Nichicons) since they’re some 21-23 years old ? Thank you again for your time.

    1. No worries Kam, check the board from above initially, the holes are plated through so some insight can be gained from above if you know what you are looking for. In reality, if you don’t have the facility or ability to test and measure component parameters, nothing should really be replaced at least until you have the machine working again as you say. I’ll say this again for the benefit of anyone reading – changing things without being properly able to test them makes no real sense. Those Nichicons are superb parts, so you need to be able to measure them to know if they should be changed. In addition, and this is critically important and misunderstood, every time you change something, you introduce the possibility of a goof, for example, a reversed cap, solder bridge, lifted trace etc. The less you do this kind of stuff, the cheaper your gear etc, the greater the chance of goofing. Multiply that out across lots of parts and you multiply the chances of the thing not working, rather than fixing it. So yes, maybe replace caps later, once you have it working. Keep in mind there are two types of CD mechs used in these machines. One has the hall effect spindle motor and one has a conventional type. They are not interchangeable, so check the wiring to the spindle motor.

  2. Hi Mike,
    Firstly, very grateful for your time in documenting various repairs and upgrades on your website! I know you’re super busy but I simply have nobody else to ask about a ‘no disc’ problem on a 506.20. Upon power up the spindle spins very briefly (0.5s ish) and the laser move up and down, and that’s it. It does this with or without a disc. Upon any other button press the laser moves up and down trying to find focus but the spindle does not spin. In your wisdom, do you think this likely to be laser or power supply?
    Regards,
    Kam

    1. Hi Kam, thanks for your question and sorry to hear about the problem you are having with your Meridian. So from what you describe, there is power to the laser, though a check with a laser power meter would confirm the TOC read attempt at disc load. Perhaps a dead spindle motor or power to the spindle motor is out? One way to check would be to sub in a new mech, but I would rather test the lines to the laser mech itself first and confirm that everything is getting power. Make sure you carefully check for dry joints on that laser power board because that was what caused the issue on my last repair unit. Mine had symptoms very similar to yours, so have a really good look with a loupe, especially at the area I discussed in the article. Let me know how you go.

  3. Hi Craig, i ‘ll be very pleased if you could suggest the correct settings parameter for my 506.24 bitt cd player. I mean pwr on+display button. New laser mounted, but only few time working again then died. I really dont’undersatand.
    Thanks anyway
    alex
    rome

    1. Hi Alex – it’s Mike BTW! The settings you mention don’t have enough of an effect to cause the player not to work. I’m hoping you took the player to a technician, in which case it must go back. There are many variables in this equation including how the work was done, exactly what mech has been installed, condition of the player and control circuitry etc. If it died, something else is wrong and must be addressed. If you lived anywhere near Perth, I’d suggest it needs to come in for a look, but you are in beautiful Rome! I hope there is a good technician nearby.

  4. hi what diameter and shape drive belt did you use? Also, in mine there’s a spring which seems to have lengthened – the drive “bumps” when it closes. – any suggestions for a replacement spring??

    1. Hi Ciaran, I don’t give out specific data on belts and things but I always use an exact replacement for the original. Regarding tray operation, check the open and closed positional microswitches, they can be slightly adjusted in most cases. The spring might be worn and of course I have a range of springs, belts and thousands of other parts here but I’d need to match them as they don’t provide details of any mechanical parts in the service manual. Try standard commercial suppliers like Farnell/Element14, RS, Mouser etc for springs, they sell sets and individually.

  5. Yes of course, i am going to get it out and play it a while to see exactly what its doing as its been stored for a while now.

    1. That’s tricky, I generally prefer to deal in person with customers and the shipping element can create problems and certainly adds to the expense.

  6. Hi, I Once owned the 506 Fantastic player, Also had the 586 dvd/cd player and was able to compare directly. The 586 was even better.My 586 has hardly been used so laser should be great but it has an issue where the display and control buttons stop working. Cd will continue playing tho. I am considering repairing this fault. Mine is the mark 1 and in the mark2 they installed a fan. Could it be overheating? Any thoughts?

    1. Hi Craig and thanks for your comment. Which 506 did you have? The 24 is better than either of the two previous 506 iterations. In terms of your 586, I would need the unit in for a proper inspection to be able to offer any really useful advice on this. Are you a Perth local?

      1. Update: I opened up the 586 dvd/cd player reseated a few connectors in there and seems to have fixed the display/ remote problem. I wish I had of tried that years ago. All the best Craig.

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