![]() ![]() One thing I only noticed now - probably unrelated to my issue, but it makes me a bit nervous: The SRAM connected to the SAA7020 is by far the hottest-running IC. Can't provoke it by heating things up with a hairdryer, nor by tapping the boards and connectors. And of course, now that the player sits on the bench, opened up and with the scope connected, the issue has not shown up over the past three hours. All at their nominal values, and nice and clean. (The mute relays are bridged, since I had suspected them to be flaky and cause the noise.) That would suggest that the problem lies further downstream, on the demodulator/decoder board, right? As suggested by LA7SJA, I have looked at the power rails again. When I have these things in front of me, I can usually figure it out in minutes, mostly by LISTENING to the player for the unique sounds it makes, but on forums it's really tough.Īs mentioned in the OP, I am confident that it is not the laser, tracking, or drive (fortunately!), since the noise also occurs while the player is sitting idle without playing a CD. You may have to try turning the bearing screw 1/4 turn clockwise if you have a CDM-1 to test if the spindle has worn a divet into it. This is often the case with Revox and Studer players as well. I have found that taking it apart and oiling it and then re-adjusting the spindle height properly can fix many "problems". The later one had a CDM-1 with the indestructible hall motor. The CDM-0 has a brush motor and is why I sold mine. I have fixed 1000's of philips based players. This can cause scratching sounds in the audio as well. I have ALSO observed the spindle motor being lazy. The player may need a touch up align on a scope. Really only scoping the RF Eye pattern will tell you. Although if it plays redbook cd's fine but has some trouble with CD-R's. Does it play a CD-R? If it does, it's NOT the laser. So you are good if you have a single sided board. Didn't even have part numbers on the laser and such. Mine had a ground plane, but it WAS a pre-production model. The "same time on both channels but different noise", as well as the fact that it also occurs in idle mode, seem quite characteristic - but I can't pinpoint the problem, and seem to be largely limited to trial-and-error since it is so sporadic. Or someone who has a creative idea where in the signal chain an error with the behaviour described above might lie. I reseated all socketed ICs, resoldered quite a few joints in the area which sees heat and thermal expansion (power transistors in the back), and inspected all joints under magnification.Īt this point I'm hoping to find someone who has seen this particular problem in a CD 100 or other early Philips player before.(Two reed relays which normally interrupt the audio output while no music is playing, to impress the listener with "zero noise".) No change. Not something I would normally do pre-emptively, but the CD 100 does run quite warm. I have replaced all electrolytic caps.What I have done is rule out the usual suspects mentioned in various threads on the net: It might well be a thermal issue which does not want to show up while the unit is open, but I might be imagining that. That's a relief, since it probably means that it is neither the laser nor the pickup/tracking circuit.ĭue to the sporadic nature of the problem, I have not been able to take any measurements while it was occuring. Once I had disabled the muting relays (see below), I realized that the noise can also occur while the player sits there idly (powered on, but not playing a CD).Mechanical bumps don't seem to start or stop the noise.This always affects both channels at the same time, but the crackles are different/uncorrelated on both channels.It sporadically emits loud crackling noises overlaying the music, sometimes followed by total silence until the sound spontaneuously comes back.Due to its history, the impressively over-engineered optomechanics, and its industrial design I am quite fond of it and would like to continue using it. I have a Philips CD 100 which I bought in 1984 - the first type of CD player sold in this part of the world, and this particular unit was my first CD player back then.
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