Just picked up a CLD-D704. Player is in good working order, though I have occasional issues were the tray closes and the unit seems to hesitate and then spits out the disc. If I close the tray again, it will usually play just fine. Same issue as in this thread where a loading belt was recommended, so I will try that: https://forum.lddb.com/viewtopic.php?f=30&t=8131

In any event, most of the time, the player fires up just fine. I upgraded from a CLD-D702 and I notice this 704 has a much louder hum when playing. Not super loud, but appreciably louder than my 702. Is this normal or anything I should be concerned about? Again other than the issue that I feel is likely a belt, the unit plays great and the image and sound is just as I would expect.

Maybe its just the extra horsepower of the 704?

Yes, that’s sounds like a typical load failure.

As for the “hum” do you mean the overall vibration of an LD at 4800rpm? The one that gets quieter on CLV discs as the movie plays but stays there all the way through CAV stuff? If so that’s something that is variable from player to player even the same model. Better players are quieter, older players are quieter. The 702/704 are sorta mid-period mid-priced so they aren’t they quietest.

The sound varies with disc, the luck of how the disc mounts, the weight of the disc, model of player, era of player, the age of the spindle motor, how many times it’s been opened, how many screws are missing, how many times it’s been dropped, etc. That’s just life with LD unless you have a high end deck.

I concur with signofzeta that the hum is normal due to the rate of spin on the disc (should be more noisy at the beginning of a CLV disc and eventually be less noisy as the disc slows down and there will be the same amount of noise for the entire runtime on a CAV disc).

And in respect comparing the 702 to 704, the former probably would be a tad more quiet because it is a heavier machine that dampens better.

Makes sense. I was surprised at how light the 704 was (relatively speaking) when I picked it up from the guy I bought it from. PQ-wise, it doesn't seem that big a jump over the 702, though I finally have an AC-3 machine, so that is worth it. I will definitely keep my 702 around as it has never let me down.

Every subsequent year probably from 1988 and on, the players were getting lighter except the really high end models. I'm sure it was because of normal cost cutting and economies of scale. Not to mention, if the player still functions fine on lesser weight, then it should still be fine (just noisier).




It may be hard to tell the difference today since most of us run our players on digital displays that add more processing to the signal. In fact, a 701/702 may look better now since the composite output doesn’t add processing like the 703/704. Thus, the latter players may be creating an over processed image that detracts on today's modern displays. As for AC3, you can still mod your 702 for AC3-RF output (although that's easier said than done for most people).




At this point, everyone should be saving as many players as one can since there are fewer working machines every year. I myself am a little overkill in respect that I have 11 players; one broken that happens to be a 702 that I plan to fix at some point. I was planning a few years ago to weed out some of these machines but I have since decided against it. Also, I wanted to have some fun with these machines and will attempt to mod all of them for AC3-RF out (just for the hell of it ).

I agree. I was initially going to sell the 702, but I will certainly keep it now.

I foolishly expected an appreciable difference in quality since what I have read of the 704, its one of the best North American players.

Right now I am working on setting both up and keeping the 702 as my main player with the 704 being used mainly for AC3 once I get a demodulator. I am still pleased to have both as they are great pieces of hardware.

Yes, keep both.
The way we are going with players its best to keep them all right now IF one plans to have a nice LD collection for anytime.

As for the sound, I remember that some discs would sound louder than others and they weren't anything like CAV or CLV etc.
Just the player sounding louder sometimes.

Probably a dumb question, but doesn't the loading belt only control the movement of the tray? If the tray opens and closes completely, how does the humming indicate the belt is loose?

Jason

After the tray closes that same belt then lifts the spindle up into the disc. You need better traction to lift the disc than you do to close the door.

If you see it in action it makes sense. That same motor/pulley/belt turns in the same direction the whole time but when the tray hits the close limit it then sort of shifts gear and begins lifting the spindle.

Could this be the same issue I have with my CLD-950?

Very likely.

The loading belt does quite a bit as signofzeta illustrated. In most LD players, there are three motors total. The loading motor, the spindle motor, and carriage motor (moves the laser pick-up up and down and around on auto reverse units).

Some players also have a tilt motor. The Pioneer DVL players have a 2nd carriage motor and the turn mechanism motor. The LD-W1 has 4 tray motors, tilt motor, clamp motor, spindle motor, carriage motor and the rotation motor.

I did not mean to insinuate that the loading belt and the hum were related. I was more relaying that I noticed issues when loading the disc that I felt were caused by a bad loading belt.

Having tested several discs out, the hum is certainly just the build quality. I checked and have found no missing screws. I played a CAV disc (Batman Mask of the Phantasm) and it was indeed quite loud. CLV discs do become quieter as the movie plays.

The room I watch movies in is not that large a space. I hooked my 702 back up and am watching on that at the moment. I will move the 704 back in once I find a demodulator. Listening to AC3 was the main reason I got this player in the first place.

I don't believe anyone was insinuating anything of the sort.

I think "jseach" confused some of us with his question and threw us off topic. I was thinking his perception of hum was maybe the sound of a slipping belt that could be described as the same.

Well I was thinking more the title of my thread plus the my opening statements about a loading belt might throw some off is all. No harm no foul.