I stumbled upon a Marantz CD-30 II for $7 at a thrift store the other day. She looked up at me with that sad laser eye, and I just couldn't let her stay there in the cold. I brought her home, and she turned out, unsurprisingly, to be a sick little pup.
The CD-30 II is the second generation of a Japanese made model. Same as the CD-40 (a very slightly more internet extant model, but still obscure), but without a remote. Has the plug and internal cable, but the remote section on the board is unpopulated. It's not a high end model by any means, but for $7 for a solid name brand it's really hard to argue, or even raise the slightest contention. Some of my favorite albums aren't available on vinyl, and I've been casually on the lookout for a decent CD player for a while. I figured I couldn't go wrong with a Marantz and my relatively low standards.
First off, it had been dropped, and the plastic facia has a dent. Not sure if it caused any damage beyond the superficial. I couldn't make anything out.
Second, the bushings suspending the CD tray had collapsed a bit over the years, so the drawer was sticking on the bottom of the facia a little. I shimmed them up with some washers of varying thickness, and now that's happy. Or at least happier. Might be a little weak. Tough to say without any reference.
I plugged it in and turned it on, and it seems to happily move through the various modes on the display.
I put a CD in it, and then things started getting a bit hinky. It occasionally doesn't recognize that it has a CD; maybe 1 time out of 6. I noticed the CD doesn't seem to be perfectly centered, but I'm not sure that's necessarily abnormal (I'm also a watchmaker, and little things like that stick out like a sore thumb). It also made a bit of noise as it spun, but again, I'm not sure if this is or isn't abnormal. When it knows it has a CD, it recognizes the correct number of tracks, and seems to shift the laser accordingly. Finally, no sound came out for 2 CDs out of 3. The third... Noise came out that sounded like a garbled mess of what is actually on the CD, but completely unintelligible. So something is alive in there...
This is my first time even looking at the guts of something like this. I have no idea where to even start. I have no idea what's normal or not. Could someone give me some clues?
The CD-30 II is the second generation of a Japanese made model. Same as the CD-40 (a very slightly more internet extant model, but still obscure), but without a remote. Has the plug and internal cable, but the remote section on the board is unpopulated. It's not a high end model by any means, but for $7 for a solid name brand it's really hard to argue, or even raise the slightest contention. Some of my favorite albums aren't available on vinyl, and I've been casually on the lookout for a decent CD player for a while. I figured I couldn't go wrong with a Marantz and my relatively low standards.
First off, it had been dropped, and the plastic facia has a dent. Not sure if it caused any damage beyond the superficial. I couldn't make anything out.
Second, the bushings suspending the CD tray had collapsed a bit over the years, so the drawer was sticking on the bottom of the facia a little. I shimmed them up with some washers of varying thickness, and now that's happy. Or at least happier. Might be a little weak. Tough to say without any reference.
I plugged it in and turned it on, and it seems to happily move through the various modes on the display.
I put a CD in it, and then things started getting a bit hinky. It occasionally doesn't recognize that it has a CD; maybe 1 time out of 6. I noticed the CD doesn't seem to be perfectly centered, but I'm not sure that's necessarily abnormal (I'm also a watchmaker, and little things like that stick out like a sore thumb). It also made a bit of noise as it spun, but again, I'm not sure if this is or isn't abnormal. When it knows it has a CD, it recognizes the correct number of tracks, and seems to shift the laser accordingly. Finally, no sound came out for 2 CDs out of 3. The third... Noise came out that sounded like a garbled mess of what is actually on the CD, but completely unintelligible. So something is alive in there...
This is my first time even looking at the guts of something like this. I have no idea where to even start. I have no idea what's normal or not. Could someone give me some clues?
Disc clamps are magnetic and just 'drop' onto the top of the disc and so if the clamp itself looks not centred then that is absolutely normal.
The edge of the spinning disc should run 100% true as viewed from above and equally important it should run true in a vertical direction as viewed edge on at the disc edge.
Next check if the mechanics look OK is to look at the RF from the disc on a scope and judge whether the amplitude is OK and also the overall Q or quality. Amplitude is typically around 1.2 volts pk/pk for a Philips based player:
Do a forum search under my user name and DRAM and you will find several threads and posts where this has been a cause.
The edge of the spinning disc should run 100% true as viewed from above and equally important it should run true in a vertical direction as viewed edge on at the disc edge.
Next check if the mechanics look OK is to look at the RF from the disc on a scope and judge whether the amplitude is OK and also the overall Q or quality. Amplitude is typically around 1.2 volts pk/pk for a Philips based player:
Possibly marginal RF (poor quality) but also many Philips based players use a small DRAM chip to clock data in and out and these are a known failure point.
Do a forum search under my user name and DRAM and you will find several threads and posts where this has been a cause.
Unfortunately, this is not the case... The whole CD is not running on center. I don't recall seeing any wobble in the vertical axis at least.Mooly said:
Where am I looking for RF and Q? Should there be some sort of diagnostic pad setup or something?
I found an ancient looking geocities style webpage last night after posting this with a book length wall of text on how to recover most CD players. From that, my takeaway was to remove the mechanical side, clean it up real good (it doesn't look especially dirty, but it's pushing 40), and regrease the tray drive parts that have grease on them. I figure while I have it out, I'll have a better chance at sussing out the state of the drive motor bearing(s)/bushing(s). Given the observation that the CD isn't running true and the noise it makes while doing so, and points me in the direction of the motor itself being clapped out. Are these sorts of parts available?
It is vital the disc runs true and if it is wobbling around in the flat horizontal plane then something is very wrong. Make sure the disc seats correctly on the cone shaped turntable platter. Also just feel the platter and see if there is any noticeable wobble in the motor shaft. I don't know what motor these use but most budget models use similar 'Mabuchi' DC motors. Check it first.
The RF is picked up here on these resistors and on a suitable scope should look as stable as the picture in my earlier post. If you can manage to look at the lens while it is playing an outer track on a disc (use a torch and look horizontally under the disc) then the lens should be relatively still. If it is moving up and down then that means it is focused on a disc that is also moving up and down (dirt on the platter can do that). If it is wobbling side to side then that is following an eccentrically running disc. Movement in both axis should be minimal for a disc running true and level.
The RF shown here is stated as 2.5v peak/peak, the value I gave of around 1.2 volts would be that seen on pin 26 of that chip where it says HF in and before being amplified. The 2.5v is the one to measure as it will be easier to get to on those resistors.
The RF is picked up here on these resistors and on a suitable scope should look as stable as the picture in my earlier post. If you can manage to look at the lens while it is playing an outer track on a disc (use a torch and look horizontally under the disc) then the lens should be relatively still. If it is moving up and down then that means it is focused on a disc that is also moving up and down (dirt on the platter can do that). If it is wobbling side to side then that is following an eccentrically running disc. Movement in both axis should be minimal for a disc running true and level.
The RF shown here is stated as 2.5v peak/peak, the value I gave of around 1.2 volts would be that seen on pin 26 of that chip where it says HF in and before being amplified. The 2.5v is the one to measure as it will be easier to get to on those resistors.